A spherical ferroalloy powder material, a preparation method thereof and use thereof

Abstract

This invention relates to a spherical ferroalloy powder material, its preparation method, and its applications. By selecting an Fe and La-based alloy system and simultaneously adding special alloying spheroidizing and corrosion-resistant elements, spherical dispersed particles rich in Fe and containing dissolved spheroidizing elements in the initial alloy melt during solidification are dispersedly precipitated within a La-rich matrix phase. By removing the La-rich matrix phase, spherical ferroalloy powder materials with particle sizes ranging from nanometers to tens of micrometers are obtained. This method is simple and can prepare spherical ferroalloy powder materials with different morphologies, including nanometer, submicron, and micrometer sizes, showing promising applications in powder metallurgy, metal injection molding (MIM), 3D printing, magnetic materials, heat-resistant materials, high-temperature alloys, coatings, electrothermal materials, microwave absorbing materials, and magnetohydrodynamics.

Description

Technical Field

[0001] This invention relates to the field of metal powder materials technology, and in particular to a spherical iron alloy powder material, its preparation method, and its applications. Background Technology

[0002] Fe alloys are among the most widely used metallic materials. Using micro- and nano-sized Fe alloy powders as raw materials, a large number of Fe alloy materials with diverse properties can be prepared through additive manufacturing technologies such as powder metallurgy, metal injection molding (MIM), or 3D printing. Examples include Fe-Cr ferritic stainless steel, Fe-Cr-Ni austenitic stainless steel, Fe-Cr-Al electrothermal alloys, Fe-Cr-Co permanent magnets, and Fe-Cr-Si soft magnetic materials.

[0003] Spherical or near-spherical Fe alloy particles are key raw materials in powder metallurgy, powder coatings, metal injection molding (MIM), 3D printing, and magnetic materials due to their excellent flowability, uniformity, and dense powder packing. In many cases, spherical or near-spherical particles are necessary to achieve the desired application effect. Currently, spherical Fe alloy powder materials are mainly prepared by atomization, which uses high-speed fluid to directly break up liquid metals or alloys to obtain metal powder. However, due to the limitation of atomization capacity, it is generally only suitable for the preparation of spherical Fe alloy powders with a particle size of 10μm to 150μm. For spherical Fe alloy powder materials with a particle size below 10μm, especially those ranging from nanometers to several micrometers (below 10μm), atomization is difficult or impossible. Therefore, developing a method for preparing ultrafine spherical ferroalloy powder materials with a particle size ranging from nanometers to several micrometers has significant application implications. Summary of the Invention

[0004] Therefore, it is necessary to provide a method for preparing spherical iron alloy powder materials that is simple in process, low in cost, and easy to operate, addressing the aforementioned technical problems. To solve the above technical problems, the technical solution of this invention includes the following aspects:

[0005] On one hand, a method for preparing spherical iron alloy powder material is characterized by comprising the following steps:

[0006] Step 1: Select initial alloy raw materials and melt them according to the initial alloy composition ratio to obtain a homogeneous initial alloy melt; the main component of the initial alloy melt is La. x Fe y T z M a D b, where T contains at least one of Cr and V, M contains at least one of Al, Ni, Co, and Si, D contains at least one of Mo, W, and Ti, x, y, z, a, and b respectively represent the atomic percentage contents of the corresponding constituent elements, and 18% ≤ x ≤ 95.8%, 4% ≤ y ≤ 81.8%, 0.1% ≤ z ≤ 35%, 0 ≤ a ≤ 40%, 0 ≤ b ≤ 15%;

[0007] Step 2: Solidify the initial alloy melt into an initial alloy solid by rapid solidification technology; the solidification structure of the initial alloy solid includes a matrix phase and a dispersed particle phase; the melting point of the matrix phase is lower than that of the dispersed particle phase, and the dispersed particle phase is coated in the matrix phase; the volume percentage of the matrix phase in the solidification structure is not less than 40%; the average composition of the matrix phase is mainly La x1 M a1 ; the composition of the dispersed particle phase is mainly Fe y2 T z2 M a2 D b2 La x2 , where x1, a1, x2, y2, z2, a2, and b2 respectively represent the atomic percentage contents of the corresponding constituent elements, and 45% ≤ x1 ≤ 100%, 0% ≤ a1 ≤ 55%, 50% ≤ y2 ≤ 98%, 0.2% ≤ z2 < 50%, 0% ≤ a2 ≤ 30%, 0% ≤ b2 ≤ 35%, 0 < x2 ≤ 5%; the dispersed particle phase includes a considerable amount of spherical or near-spherical dispersed particle phases, and some of the spherical or near-spherical dispersed particle phases have certain dendritic characteristics; the particle size of the dispersed particle phase is 5 nm to 50 μm;

[0008] Step 3: Remove the matrix phase from the initial alloy solid and mainly retain the dispersed particle phase, thereby obtaining an iron alloy powder material mainly composed of Fe y2 T z2 M a2 D b2 La x2 ; where 50% ≤ y2 ≤ 98%, 0.2% ≤ z2 < 50%, 0% ≤ a2 ≤ 30%, 0% ≤ b2 ≤ 35%, 0 < x2 ≤ 5%; the iron alloy powder particles include a considerable amount of spherical or near-spherical particles, and some of the spherical or near-spherical iron alloy powder particles have certain dendritic characteristics; the particle size of the iron alloy powder particles is 5 nm to 50 μm.

[0009] In step 1,

[0010] Further, T contains Cr; Further, T contains V;

[0011] Furthermore, M contains Al; furthermore, M contains Ni; furthermore, M contains Co; furthermore, M contains Si;

[0012] Furthermore, 0 < a ≤ 40%; furthermore, 2.5% < a ≤ 40%, 18% ≤ x ≤ 93.3%; furthermore, 5% < a ≤ 40%, 18% ≤ x ≤ 90.8%; furthermore, 10% < a ≤ 40%, 18% ≤ x ≤ 85.8%;

[0013] Furthermore, D contains Mo; furthermore, D contains W; furthermore, D contains Ti;

[0014] Furthermore, 0 < b ≤ 15%; furthermore, 0.5% < b ≤ 15%, 18% ≤ x ≤ 95%;

[0015] Furthermore, 18% ≤ x ≤ 93.8%, 6% ≤ y ≤ 81.8%; preferably, 18% ≤ x ≤ 89.8%, 10% ≤ y ≤ 81.8%;

[0016] Furthermore, 18% ≤ x ≤ 95%, 0.5% ≤ z ≤ 35%; furthermore, 18% ≤ x ≤ 94%, 1% ≤ z ≤ 35%; preferably, 18% ≤ x ≤ 92%, 3% ≤ z ≤ 35%; preferably, 18% ≤ x ≤ 90%, 5% ≤ z ≤ 35%;

[0017] Furthermore, 18% ≤ x ≤ 80%; furthermore, 18% ≤ x ≤ 70%; furthermore, 18% ≤ x ≤ 60%; furthermore, 18% ≤ x ≤ 50%;

[0018] Since rare earth La is a large atom, even if it has a low atomic percentage content in the initial alloy melt, it still corresponds to a large volume percentage content, and the volume percentage content is the key to whether the dispersed particle phase can be dispersed. For example, in an alloy with an atomic percentage composition of La 20 Fe 75 Cr5, according to the atomic weights and densities of each element, the volume percentage content of the La matrix can be calculated to be 44.35%. When most of the M-type elements also enter the matrix phase, the volume percentage content of the matrix phase can be further increased.

[0019] Furthermore, y > z, that is, the atomic percentage content of Fe in the initial alloy melt is higher than the atomic percentage content of T-type elements;

[0020] In the second step,

[0021] According to the La-Fe, La-Cr, La-V, Fe-Cr, Fe-V, and Cr-V phase diagrams, the melting points of Fe, Cr, and V are all higher than that of La. Fe, Cr, and V do not form intermetallic compounds with La and are not significantly dissolved in solid. Furthermore, Fe-Cr, Fe-V, and Cr-V are all infinitely dissolved alloy systems. Therefore, during the solidification of the initial alloy melt, the dispersed particle phase, mainly composed of Fe, Cr, and V, precipitates first from the alloy melt, while the matrix phase, mainly composed of La, solidifies last. Moreover, the solidified alloy structure does not contain intermetallic compounds composed of La and Fe, Cr, and V. In other words, during the process of solidifying the initial alloy melt into an initial alloy solid using rapid solidification technology, the solidified structure of the initial alloy solid includes a La-rich matrix phase and a dispersed particle phase rich in Fe, Cr, or (and) V. The melting point of the matrix phase is lower than that of the dispersed particle phase, and the dispersed particle phase is encapsulated within the matrix phase.

[0022] Further, the initial alloy melt solidification rate is higher than 20 K / s; preferably, the initial alloy melt solidification rate is higher than 50 K / s; preferably, the initial alloy melt solidification rate is higher than 100 K / s; preferably, the initial alloy melt solidification rate is higher than 250 K / s; and even more preferably, the initial alloy melt solidification rate is higher than 500 K / s.

[0023] Further, the shape of the initial alloy solid has at least one dimension with a scale less than 10 mm in the three-dimensional direction; preferably, the shape of the initial alloy solid has at least one dimension with a scale less than 5 mm in the three-dimensional direction; preferably, the shape of the initial alloy solid has at least one dimension with a scale less than 2 mm in the three-dimensional direction; preferably, the shape of the initial alloy solid has at least one dimension with a scale less than 1 mm in the three-dimensional direction; preferably, the shape of the initial alloy solid has at least one dimension with a scale less than 500 μm in the three-dimensional direction; preferably, the shape of the initial alloy solid has at least one dimension with a scale less than 100 μm in the three-dimensional direction.

[0024] The higher the solidification rate of the initial alloy melt, the smaller the minimum scale of the shape of the obtained initial alloy solid in three dimensions; for example, by the copper roller spinning method at approximately 10 6 K / s ~ 10 7At a solidification rate of about 25 K / s, an initial alloy solid thin strip with a thickness of about 25 μm can be obtained; by the copper mold casting method at a solidification rate of about 100 K / s, an alloy bar with a diameter of about 5 mm or a thick plate with a thickness of about 5 mm can be obtained; generally, the particle size of the dispersed particle phase is negatively correlated with the solidification rate of the initial alloy melt, that is: the greater the solidification rate of the initial alloy melt, the smaller the particle size of the dispersed particle phase. However, different elements with different solid solubilities or the same element with different solid solubility amounts may hinder the normal growth of the dispersed particle phase in different ways, which may cause a certain degree of change in this rule; for example, the spheroidization trend will cause the particle phase to merge and re-spheroidize during solidification; or inhibit the nucleation rate and increase the growth rate, etc. For example, when there is no solid solution of certain elements, the average particle size of the dispersed particle phase obtained at a certain cooling rate is 1 μm, but after solid solution of certain elements, spherical dispersed particle phases can be obtained at the same cooling rate, and the average particle size of the particle phase is 5 μm.

[0025] Furthermore, the shape of the initial alloy solid includes at least one of strip, ribbon, sheet, filament, and granular; preferably, the shape of the initial alloy solid includes at least one of strip, ribbon, and sheet;

[0026] Furthermore, the solidification techniques for preparing the initial alloy solid include at least one of melt spinning, rapid solidification flaking, casting, continuous casting, atomization powder making, and melt drawing;

[0027] Furthermore, the initial alloy solid is strip-shaped, and the strip thickness is 5 μm to 5 mm;

[0028] Furthermore, the volume percentage of the matrix phase in the solidification structure is not less than 45%; furthermore, the volume percentage of the matrix phase in the solidification structure is not less than 50%;

[0029] Furthermore, 0 < x2 < x < x1, that is, during the solidification process of the initial alloy melt, La is enriched in the matrix phase, and at the same time, there is a small amount of La in the dispersed particle phase;

[0030] Since La is a large atom in the matrix phase, even if the atomic percentage of La in the matrix phase is as low as 45%, calculated by volume percentage, the volume percentage content of La is still much greater than 50%, so the matrix phase is still mainly composed of La. [[ID=二十]]

[0031] Furthermore, 50% ≤ x1 ≤ 100%, 0% ≤ a1 ≤ 50%;

[0032] Furthermore, the La element exists in Fe in the form of solid solution y2 T z2 M a2 D b2 La x2In the dispersed particle phase;

[0033] Furthermore, 0 < x2 ≤ 3%;

[0034] Furthermore, 0 < y < y2, that is, during the solidification process of the initial alloy melt, Fe is enriched in Fe y2 T z2 M a2 D b2 La x2 In the dispersed particle phase;

[0035] Furthermore, 50% ≤ y2 ≤ 95%; Furthermore, 50% ≤ y2 ≤ 90%; Furthermore, 50% ≤ y2 ≤ 85%; Furthermore, 50% ≤ y2 ≤ 75%;

[0036] Furthermore, 0 < z < z2, that is, during the solidification process of the initial alloy melt, T-type elements are enriched in Fe y2 T z2 M a2 D b2 La x2 In the dispersed particle phase;

[0037] Furthermore, 1% ≤ z2 < 50%; Furthermore, 3% ≤ z2 < 50%; Furthermore, 5% ≤ z2 < 50%; Furthermore, 10% ≤ z2 < 50%;

[0038] Furthermore, y2 > z2, that is, Fe y2 T z2 M a2 D b2 La​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​Further, 1% ≤ a2 ≤ 30%; Further, 3% ≤ a2 ≤ 30%; Further, 5% ≤ a2 ≤ 30%; Further, 10% ≤ a2 ≤ 30%;

[0042] Further, the M-type elements exist in Fe in a solid solution form y2 T z2 M a2 D b2 La x2 in the dispersed particle phase;

[0043] The characteristics of the M-type elements are that during the solidification process of the initial alloy melt, the M-type elements are enriched in La x1 M a1 in the matrix phase. At the same time, the M-type elements are also solid-solved with a considerable content in Fe y2 T z2 M a2 D b2 La x2 in the dispersed particle phase.

[0044] Furthermore, when b = 0, b2 = b = 0; when 0 < b ≤ 15%, 0 < b < b2, that is, during the solidification process of the initial alloy melt, the D-type elements are enriched in Fe y2 T z2 M a2 D b2 La x2 in the dispersed particle phase;

[0045] Further, 0.5% ≤ b2 ≤ 35%; Further, 1% ≤ b2 ≤ 35%; Further, 3% ≤ b2 ≤ 35%; Further, 5% ≤ b2 ≤ 35%;

[0046] Further, the D-type elements exist in Fe in a solid solution form y2 T z2 M a2 D b2 La x2 in the dispersed particle phase;

[0047] Specifically, when 0 < a ≤ 40%, according to the Al-Fe and Si-Fe phase diagrams, Al and Si have a large solubility in iron, while Fe-Ni and Fe-Co are completely soluble. Therefore, M-type elements can be dissolved in the Fe-rich dispersed particle phase. According to the Al-La, Ni-La, Co-La, and Si-La phase diagrams, Al, Ni, Co, and Si can all form La-rich intermetallic compounds with La. Since the melting point of the La-rich intermetallic compound is lower than that of the Fe-rich dispersed particles, during the solidification process of the initial alloy melt, a certain amount of M-type elements are first dissolved in the Fe-rich dispersed particle phase, and the remaining M-type elements then combine with La to form the La-rich intermetallic compound matrix; if there is still surplus La, La x1 M a1 In addition to the La-rich intermetallic compound formed by M-type elements and La, the matrix phase also includes the surplus La phase.

[0048] When 0 < b ≤ 15%, according to the La-Ti, La-W, and La-Mo phase diagrams, Ti, W, and Mo do not form intermetallic compounds with La and do not show significant solubility either. Therefore, during the solidification process of the initial alloy melt, Ti, W, and Mo will not enter the La-rich matrix phase; according to the Fe-Ti, Fe-Mo, and Fe-W phase diagrams, Ti and W have a solubility of about 10 at.% in Fe, and Mo has a solubility of about 20 at.% in Fe; at the same time, according to the Cr-Ti, Cr-Mo, and Cr-W phase diagrams, Cr is completely mutually soluble with Ti, Mo, and W; according to the V-Ti, V-Mo, and V-W phase diagrams, V is completely mutually soluble with Ti, Mo, and W; therefore, the elemental affinity of D-type elements Ti, W, and Mo with La is extremely poor, the affinity with Fe is good, and the elemental affinity with Cr and V is excellent. When the initial alloy melt contains D-type elements and Fe, Cr, and V elements, during the solidification process of the initial alloy melt, the selected D-type elements will be enriched in Fe y2 T z2 M a2 D b2 La x2 the dispersed particle phase;

[0049] It should be noted that although Ti, Zr, and Hf are homologous elements, and Zr and Hf do not form intermetallic compounds with La and do not show significant solubility either, different from Ti, since Zr and Hf also have almost no solubility in Fe, Cr, and V, they can only form intermetallic compounds with each other; therefore, if the initial alloy melt contains Zr and Hf, Zr and Hf will hardly dissolve in Fe y2 T z2 M a2 D b2 La x2 the dispersed particle phase, but in Fe y2 Tz2 M a2 D b2 La x2 In addition to the dispersed particulate phase, dendritic intermetallic compound phases of Zr, Hf, Fe, Cr, and V are also formed, as shown in Comparative Example 3. These intermetallic compounds are not the iron alloy phases of interest in this application, which are mainly based on solid solution alloying.

[0050] Similarly, although Nb, Ta, and V are elements in the same group, and Nb and Ta do not form intermetallic compounds with La and are not significantly dissolved in solid, unlike Mo, W, Ti, and V, Nb and Ta have extremely low solid solubility in Fe, Cr, and V, and can only form intermetallic compounds with each other. Therefore, if the initial alloy melt contains Nb and Ta, Nb and Ta will not form intermetallic compounds with La. y2 T z2 M a2 D b2 La x2 The solid solubility in dispersed granular phases is very low, existing only in very small amounts or not at all. If the initial alloy melt contains a large amount of Nb and Ta, Nb and Ta will react with Fe. y2 T z2 M a2 D b2 La x2 Besides the presence of a very small amount of dispersed particulate phase, it may also generate dendritic intermetallic compound phases of Nb, Ta, Fe, Cr, and V, as shown in Comparative Example 4. These intermetallic compounds are not the iron alloy phases of interest in this application, which are mainly characterized by solid solution alloying.

[0051] When the initial alloy melt contains only La and Fe, and the solidification rate of the alloy melt is higher than 10 6 At a freezing rate of K / s, a certain amount of near-spherical Fe phase particles with insufficient dendrite growth at the nanoscale (below 90 nm) can be obtained. This is because at such a high cooling rate, even if the Fe phase particles have a strong tendency to dendrite, they do not have enough time to grow and thus solidify and precipitate at the nanoscale as near-spherical Fe phase particles with insufficient dendrite growth. However, since both La and Fe are easily oxidized and readily react with acid solutions to dissolve, even if an initial alloy solid composed of near-spherical Fe phase particles below 90 nm and a La matrix is ​​prepared through an ultra-high solidification rate, it is difficult to separate the La matrix from the near-spherical Fe phase particles through acid solution reaction while retaining the near-spherical Fe phase particles (the nano-Fe phase particles will also dissolve).

[0052] Generally, the solidification rate of pure La-Fe alloy melt is less than 10. 6At a solidification rate of 10 K / s, only dendritic Fe phase particles can be obtained, and it is difficult to obtain spherical or near-spherical Fe phase particles. For example, even if the solidification rate of La-Fe alloy melt is as high as 10 5 At a solidification rate of K / s, La-Fe alloy strips with a diameter of approximately 100 μm were obtained, in which the dispersed particle phase was still mainly dendritic in shape, as shown in Comparative Example 2. However, if the solidification rate of the La-Fe alloy melt is less than 500 K / s, the dispersed particle phase becomes a fully grown dendritic phase with a larger particle size. After removing the matrix phase, the obtained dendritic Fe phase dendrites are intertwined and fibrous, as shown in Comparative Example 1.

[0053] When the initial alloy melt contains La and Fe, and also contains high-melting-point elements such as Cr, V, Mo, W, and Ti, especially T-type elements such as Cr and / or V that can form a complete solid solution with Fe, the first precipitate during the solidification process are Fe-rich primary crystal particles with T-type elements dissolved in them. Due to the special solid solution of these T-type elements, the original crystal lattice formation rules are disrupted, hindering the growth of Fe-rich dendritic phases along specific crystal plane orientations, causing the Fe-rich primary crystal particles with T-type elements dissolved in them to tend to spheroidize. The higher the content of T-type elements dissolved in the Fe-rich primary crystal phase, the larger the spherical or near-spherical dispersed particle phase can be obtained at a lower melt cooling rate. Therefore, T-type elements are the key to the spheroidization of Fe-rich primary crystal particles discovered in this invention, especially when the size of the Fe-rich dispersed particles is large.

[0054] Furthermore, T-type elements include at least one of the corrosion-resistant elements Cr and V. The solid solution formed by these elements with Fe constitutes stainless steel (V's corrosion resistance is even higher than Cr). Therefore, the solid solution of T-type elements greatly enhances the corrosion resistance of the Fe-rich dispersed particle phase. Since the matrix phase is mainly composed of easily corroded La, it can be easily corroded away by reacting with an acid solution of a certain concentration, thus obtaining dispersed Fe-rich phase particles. With the significantly enhanced corrosion resistance of the Fe-rich phase dispersed particles, a concentration greater than 10... 6 A cooling rate of K / s was used to prepare an initial alloy solid containing T and D type elements in the form of nano-iron-rich spherical particles. At the same time, the high corrosion resistance of the nano-iron-rich spherical particles containing T and D type elements was used to separate them from the La-rich matrix by acid reaction, thus obtaining nano-sized iron-rich spherical particles.

[0055] M-type elements include at least one of Al, Ni, Co, and Si, all of which are key elements in commercial ferroalloys. For example, Al is one of the key elements in Fe-Cr-Al electrothermal alloys and thermal spray coatings; Ni is one of the key elements in austenitic stainless steel Fe-Cr-Ni; Co is one of the key elements in Fe-Cr-Co permanent magnets; and Si is one of the key elements in Fe-Cr-Si soft magnetic materials. According to actual research results, during the solidification process of the initial alloy melt, since the matrix is ​​also enriched with a large number of M-type elements, the atomic percentage solid solution content of Si in Fe-rich phase dispersed particles generally does not exceed 8%, and a large amount of Si needs to be added to the initial alloy melt to achieve this; the atomic percentage solid solution content of Ni in Fe-rich phase dispersed particles generally does not exceed 12%; Al and Co both have considerable solid solution content in Fe-rich phase dispersed particles (see examples), and the atomic percentage solid solution content can even exceed 20%; and most of the above-mentioned commercial ferroalloys do not have very high requirements for the content values ​​of M-type elements, making it possible to prepare commercial ferroalloy powders that meet the above-mentioned relevant compositions.

[0056] When the initial alloy melt contains M-type elements, some of these elements also exist in the Fe-rich phase dispersed particles through solid solution. Therefore, M-type elements generally have a positive effect on the spheroidization of Fe-rich phase dispersed particles, as shown in Examples 13 and 14. Furthermore, both M-type elements and La readily react with acid solutions. Therefore, M-type elements and La in the matrix phase can be removed through acid corrosion to obtain freely dispersed Fe-rich phase dispersed particles. If the poor chemical reactivity between La and M-type elements is utilized, and La in the matrix phase is primarily removed using a suitable acid solution based on the dealloying principle, a composite powder of freely dispersed Fe-rich phase dispersed particles and nanoporous M-type elements can be obtained.

[0057] Group D elements include high-melting-point elements such as Mo, W, and Ti. Although these elements do not have the same high solid solubility in Fe as Group T elements (which are completely dissolved in Fe), Group D elements have a 10%-20% solid solubility in Fe and are completely dissolved in Group T elements. Therefore, appropriately adding high-melting-point elements such as Mo, W, and Ti to the initial alloy melt can enhance the sphericity and corrosion resistance of Fe-rich phase dispersions, while also significantly improving their melting point and heat resistance. Examples include the role of Ti in commercial austenitic stainless steel 1Cr18Ni9Ti and the role of Mo in commercial ultra-high temperature Fe-Cr-Al-Mo electrothermal alloys.

[0058] In summary, based on the La-Fe alloy, the types of T-type, M-type, and D-type elements in this application are the result of careful design and selection. This selection ensures that during the initial solidification of the alloy melt, Fe, T-type, and D-type elements are primarily present in Fe. y2T z2 M a2 D b2 La x2 In the dispersed particulate phase, elements of type M are partially present in Fe. y2 T z2 M a2 D b2 La x2 In the dispersed particulate phase, La and M-type elements are mainly found in La. x1 M a1 In the matrix phase. Meanwhile, in Fe... y2 T z2 M a2 D b2 La x2 In the dispersed particulate phase, M-type elements also have considerable solid solubility, while La has relatively low solid solubility. This ingenious design ensures the spheroidization tendency of the dispersed particles through T-type elements, while simultaneously improving their corrosion resistance, which is beneficial for the separation of the dispersed particulate phase from the matrix phase through corrosion reaction.

[0059] The spheroidization of Fe-rich dispersed particles is achieved by suppressing the formation and growth of Fe-rich dendrites through solid solution alloying with special elements and control of melt cooling rate. The higher the content of T-type elements in the Fe-rich dispersed particle phase, or the higher the total content of solid-solution elements including T-type elements, or the higher the melt cooling rate, the easier it is to form spherical or near-spherical Fe-rich dispersed particles. Therefore, to achieve the same spheroidization effect, a lower cooling rate can be used when the content of solid-solution elements in the Fe-rich dispersed particle phase is higher; conversely, a higher cooling rate is required when the content of solid-solution elements is lower. In practice, by adjusting parameters, the volume percentage of spherical or near-spherical dispersed particles in all dispersed particle phases can approach 100%, but cannot reach 100%.

[0060] Furthermore, the sphericity (sphericity) of the spherical or near-spherical dispersed particle phase exceeds 50%;

[0061] Furthermore, the sphericity of the spherical or near-spherical dispersed particle phase exceeds 70%;

[0062] Furthermore, the sphericity of the spherical or near-spherical dispersed particle phase exceeds 85%;

[0063] Furthermore, the sphericity of the spherical or near-spherical dispersed particle phase exceeds 95%;

[0064] Furthermore, the volume percentage of spherical or near-spherical dispersed particles in all dispersed particle phases is greater than 10%;

[0065] Note: For ease of expression, this application uses "spherical" in some places and "spherical or near-spherical" in others. In fact, the term "spherical" as used throughout this application includes both spherical and near-spherical shapes, because there is no ideal sphere in reality.

[0066] Since pure La-Fe alloys can hardly obtain spherical dispersed particle phases using the aforementioned methods; or require extremely high cooling rates to obtain near-spherical Fe phase particles smaller than 90 nm, and it is also difficult to obtain such nanoparticles by acid reaction with the La matrix (nano Fe particles will also react with acid and be dissolved). Therefore, through alloy design, by adding corrosion-resistant elements Cr or (and) V, or by simultaneously adding a large number of D-type elements, if the volume percentage of spherical or near-spherical dispersed particle phases in all dispersed particle phases is greater than 10%, it can be considered that a considerable amount of spherical or near-spherical dispersed particle phases has been obtained;

[0067] Furthermore, the volume percentage of spherical or near-spherical dispersed particles in all dispersed particle phases is greater than 25%;

[0068] Furthermore, the shape of the dispersed particulate phase is mainly spherical or nearly spherical;

[0069] Furthermore, the volume percentage of spherical or near-spherical dispersed particles in all dispersed particle phases is greater than 50%;

[0070] Furthermore, the volume percentage of spherical or near-spherical dispersed particles in all dispersed particle phases is greater than 75%;

[0071] Furthermore, the volume percentage of spherical or near-spherical dispersed particles in all dispersed particle phases is greater than 90%;

[0072] Furthermore, the volume percentage of spherical or near-spherical dispersed particles in all dispersed particle phases is greater than 95%;

[0073] Generally, when the content of T-type elements in the Fe-rich dispersed particle phase exceeds 2%, or the total content of solid-solidified elements including T-type elements exceeds 4%, and the cooling rate of the melt exceeds 500 K / s, the volume percentage of spherical or near-spherical dispersed particle phase in all dispersed particle phases is greater than 50%.

[0074] Furthermore, when the content of T-type elements dissolved in the Fe-rich dispersed particle phase exceeds 4%, or the total content of dissolved elements including T-type elements exceeds 8%, and the cooling rate of the melt exceeds 250 K / s, the volume percentage of spherical or near-spherical dispersed particle phase in all dispersed particle phases is greater than 50%.

[0075] Furthermore, when the content of T-type elements dissolved in the Fe-rich dispersed particle phase exceeds 8%, or the total content of dissolved elements including T-type elements exceeds 12%, and the cooling rate of the melt exceeds 100 K / s, the volume percentage of spherical or near-spherical dispersed particle phase in all dispersed particle phases is greater than 50%.

[0076] Furthermore, when the content of T-type elements dissolved in the Fe-rich dispersed particle phase exceeds 12%, or the total content of dissolved elements including T-type elements exceeds 18%, and the cooling rate of the melt exceeds 50 K / s, the volume percentage of spherical or near-spherical dispersed particle phase in all dispersed particle phases is greater than 50%.

[0077] Furthermore, when the content of T-type elements dissolved in the Fe-rich dispersed particle phase exceeds 16%, or the total content of dissolved elements including T-type elements exceeds 25%, and the cooling rate of the melt exceeds 20 K / s, the volume percentage of spherical or near-spherical dispersed particle phase in all dispersed particle phases is greater than 50%.

[0078] Furthermore, when the content of T-type elements dissolved in the Fe-rich dispersed particle phase exceeds 16%, or the total content of dissolved elements including T-type elements exceeds 25%, and the cooling rate of the melt exceeds 100 K / s, the volume percentage of spherical or near-spherical dispersed particle phase in all dispersed particle phases is greater than 95%.

[0079] Furthermore, when the average particle size of the dispersed particulate phase exceeds 0.25 μm, a dispersed particulate phase with a sphericity exceeding 85% can still be obtained;

[0080] Furthermore, when the average particle size of the dispersed particle phase exceeds 0.25 μm, a dispersed particle phase with a sphericity exceeding 85% can still be obtained by controlling the cooling rate and alloy composition.

[0081] Furthermore, when the average particle size of the dispersed particle phase exceeds 0.5 μm, a dispersed particle phase with a sphericity exceeding 85% can still be obtained by controlling the cooling rate and alloy composition.

[0082] Furthermore, when the average particle size of the dispersed particle phase exceeds 1 μm, a dispersed particle phase with a sphericity exceeding 85% can still be obtained by controlling the cooling rate and alloy composition.

[0083] Furthermore, when the average particle size of the dispersed particle phase exceeds 3 μm, a dispersed particle phase with a sphericity of over 85% can still be obtained by controlling the cooling rate and alloy composition.

[0084] Furthermore, the partial spherical or near-spherical dispersed particle phase contains certain dendritic features, which means that protruding short dendrites grow on the partial spherical or near-spherical dispersed particle phase, making the entire spherical or near-spherical dispersed particle phase have shape characteristics similar to a "coronavirus" (the protruding short dendrites growing on the spherical or near-spherical dispersed particle phase correspond to the crown-shaped protrusions on the "coronavirus" sphere);

[0085] Furthermore, the number of protruding short dendrites is one or more, and the length of their further protrusion from the spherical surface is less than the radius of the spherical particle; see the embodiment for specific shape;

[0086] Furthermore, the number of protruding short dendrites is one or more, and the length of their further protrusion from the spherical surface is less than half the radius of the spherical particle;

[0087] Although these incompletely spheroidized protruding short dendrites have some influence on the sphericity of the granular phase, the sphericity of the spherical granular phase to which the protruding short dendrites grow is already very high. The protruding short dendrites are relatively short and are generally symmetrically and uniformly distributed on the particle surface. Therefore, even if some spherical or near-spherical dispersed granular phases contain the feature of incompletely spheroidized protruding short dendrites, these particles still belong to the category of spherical or near-spherical particles with high sphericity and fall within the statistical category of spherical or near-spherical particles.

[0088] Furthermore, the dispersed particle phase is primarily spherical or nearly spherical in shape; in addition, the dispersed particle phase also contains a small amount of typical dendritic particles. These dendritic particles exhibit typical dendritic morphology, do not appear spherical, and do not fall within the statistical scope of spherical or nearly spherical particles.

[0089] The dispersed particle phase is mainly spherical or near-spherical in shape, and some of the spherical or near-spherical dispersed particle phases contain certain dendritic features; at the same time, the dispersed particle phase also contains a small amount of typical dendritic particle phase. The presence of these two dendritic features is a unique characteristic of the iron-rich dispersed particle phase obtained through this application.

[0090] Furthermore, the length of the protruding short dendrites, measured from the spherical surface, is less than one-third of the radius of the spherical grain;

[0091] Furthermore, the length of the protruding short dendrites, measured from the spherical surface, is less than one-fifth of the radius of the spherical grain;

[0092] Furthermore, the particle size of the dispersed particulate phase is 5 nm to 40 μm;

[0093] Further, the particle size of the dispersed particulate phase is 5 nm to 30 μm; further, the particle size of the dispersed particulate phase is 5 nm to 20 μm; further, the particle size of the dispersed particulate phase is 5 nm to 10 μm.

[0094] Furthermore, the particle size of the dispersed particulate phase is 100 nm to 50 μm;

[0095] Furthermore, the particle size of the dispersed particulate phase is 250 nm to 50 μm;

[0096] Furthermore, the particle size of the dispersed particulate phase is 500 nm to 50 μm;

[0097] Furthermore, the particle size of the dispersed particulate phase is 5 nm to 100 nm;

[0098] Furthermore, the particle size of the dispersed particulate phase is 5 nm to 50 nm;

[0099] Since the size of the dispersed particle phase is negatively correlated with the solidification rate of the initial alloy melt, that is, the higher the solidification rate, the smaller the particle size of the dispersed particle phase, the smaller the particle size of the dispersed particle phase, the higher the solidification rate of the initial alloy melt, the higher the spheroidization rate of the dispersed particle phase, and the higher the volume percentage of spherical or near-spherical dispersed particle phase in all dispersed particle phases.

[0100] Furthermore, the number of single crystal particles in the dispersed particulate phase accounts for no less than 60% of the total number of particles.

[0101] In step three, since the main component is Fe y2 T z2 M a2 D b2 La x2 The ferroalloy powder material is obtained by removing the matrix phase from the initial alloy solid and retaining the dispersed particle phase. Therefore, the characteristics of the ferroalloy powder material (including particle shape) are the characteristics corresponding to the dispersed particles in step two. These characteristics are detailed in step two.

[0102] Furthermore, the method for removing the matrix phase and retaining the dispersed particulate phase includes at least one of acid solution dissolution reaction removal and matrix oxidation-pulverization removal.

[0103] When using acid solution reaction for removal, the appropriate type and concentration of acid should be selected, with the selection criterion being to ensure that the average component is mainly La. x1 M a1 The matrix phase transforms into ions that enter the solution, while the main component is Fe. y2 T z2 Ma2 D b2 La x2 The dispersed particulate phase hardly reacts with the corresponding acid, thus achieving the removal of the matrix phase and yielding a product whose main component is Fe. y2 T z2 M a2 D b2 La x2 Ferroalloy powder materials; or select appropriate acid types and concentrations, the selection criterion being to ensure that the average composition is mainly La. x1 M a1 The matrix is ​​a phase-change nanoporous M (primarily corroded La), while the main component is Fe. y2 T z2 M a2 D b2 La x2 The dispersed particulate phase hardly reacts with the corresponding acid, yielding nanoporous M and Fe y2 T z2 M a2 D b2 La x2 Composite powders with dispersed particles;

[0104] When Fe contains Cr and V in solid solution, it is the composition of ferritic stainless steel, with Fe as the main component. y2 T z2 M a2 D b2 La x2 The dispersed particulate phase exhibits excellent acid corrosion resistance, while La and M-type elements readily react with acid solutions. Therefore, the La-rich matrix phase can be easily removed to obtain a product primarily composed of Fe. y2 T z2 M a2 D b2 La x2 Ferroalloy powder materials.

[0105] Since La is highly susceptible to oxidation and pulverization in air, in addition to acid dissolution, the La-rich matrix phase in the initial alloy solid can also be removed by dry methods. Once the La-rich matrix is ​​oxidized and pulverized, the Fe-rich dispersed particles automatically detach. Due to their magnetic properties, these Fe-rich particles can be collected using a magnetic field, thus separating them from the La-rich matrix phase.

[0106] Furthermore, the oxidation-pulverization process of the initial alloy solid La-rich matrix phase is accelerated under heat treatment; through heat treatment heating, the La-rich matrix phase is rapidly oxidized and pulverized, thereby improving separation efficiency. Due to the addition of elements such as Cr and V, the oxidation resistance of the Fe-rich particle phase is enhanced; by controlling the heating temperature, oxidation of the Fe-rich particles will not occur.

[0107] Further, the heat treatment temperature is 50℃~1000℃; preferably, the heat treatment temperature is 50℃~600℃; preferably, the heat treatment temperature is 50℃~200℃.

[0108] Furthermore, the volume percentage of spherical or near-spherical ferroalloy powder particles in all ferroalloy powder particles can be infinitely close to 100%, but cannot reach 100%. That is to say, the shape of the ferroalloy powder particles is mainly spherical or near-spherical, and some spherical or near-spherical ferroalloy powder particles contain dendritic features of insufficient spheroidization;

[0109] Furthermore, the sphericity (sphericity) of the spherical or near-spherical ferroalloy powder particles exceeds 50%;

[0110] Furthermore, the sphericity of the spherical or near-spherical ferroalloy powder particles exceeds 70%;

[0111] Furthermore, the sphericity of the spherical or near-spherical ferroalloy powder particles exceeds 85%;

[0112] Furthermore, the sphericity of the spherical or near-spherical ferroalloy powder particles exceeds 95%;

[0113] Furthermore, the volume percentage of spherical or near-spherical ferroalloy powder particles in all ferroalloy powders is greater than 10%.

[0114] Furthermore, the volume percentage of spherical or near-spherical ferroalloy powder particles in all ferroalloy powders is greater than 25%;

[0115] Furthermore, the iron alloy powder particles are mainly spherical or near-spherical in shape;

[0116] Furthermore, the volume percentage of spherical or near-spherical ferroalloy powder particles in all ferroalloy powders is greater than 50%.

[0117] Furthermore, the volume percentage of spherical or near-spherical ferroalloy powder particles in all ferroalloy powders is greater than 75%;

[0118] Furthermore, the volume percentage of spherical or near-spherical ferroalloy powder particles in all ferroalloy powders is greater than 90%.

[0119] Furthermore, the volume percentage of spherical or near-spherical ferroalloy powder particles in all ferroalloy powders is greater than 95%;

[0120] Generally, when the content of T-type elements in solid solution in ferroalloy powder particles exceeds 2%, or the total content of solid solution elements including T-type elements exceeds 4%, and the cooling rate of the melt exceeds 500 K / s, the volume percentage of spherical or near-spherical ferroalloy powder particles in all ferroalloy powder particles is greater than 50%.

[0121] Furthermore, when the content of T-type elements dissolved in the ferroalloy powder particles exceeds 4%, or the total content of dissolved elements including T-type elements exceeds 8%, and the cooling rate of the melt exceeds 250 K / s, the volume percentage of spherical or near-spherical ferroalloy powder particles in all ferroalloy powder particles is greater than 50%.

[0122] Furthermore, when the content of T-type elements dissolved in the ferroalloy powder particles exceeds 8%, or the total content of dissolved elements including T-type elements exceeds 12%, and the cooling rate of the melt exceeds 100 K / s, the volume percentage of spherical or near-spherical ferroalloy powder particles in all ferroalloy powder particles is greater than 50%.

[0123] Furthermore, when the content of T-type elements dissolved in the ferroalloy powder particles exceeds 12%, or the total content of dissolved elements including T-type elements exceeds 18%, and the cooling rate of the melt exceeds 50 K / s, the volume percentage of spherical or near-spherical ferroalloy powder particles in all ferroalloy powder particles is greater than 50%.

[0124] Furthermore, when the content of T-type elements dissolved in the ferroalloy powder particles exceeds 16%, or the total content of dissolved elements including T-type elements exceeds 25%, and the cooling rate of the melt exceeds 20 K / s, the volume percentage of spherical or near-spherical ferroalloy powder particles in all ferroalloy powder particles is greater than 50%.

[0125] Furthermore, when the content of T-type elements dissolved in the ferroalloy powder particles exceeds 16%, or the total content of dissolved elements including T-type elements exceeds 25%, and the cooling rate of the melt exceeds 100 K / s, the volume percentage of spherical or near-spherical ferroalloy powder particles in all ferroalloy powder particles is greater than 95%.

[0126] Furthermore, the presence of certain dendritic features in the partially spherical or near-spherical ferroalloy powder particles refers to the growth of protruding short dendrites on some of the spherical or near-spherical ferroalloy powder particles, which gives the entire spherical or near-spherical ferroalloy powder particles a shape similar to a "coronavirus" (the protruding short dendrites growing on the spherical or near-spherical ferroalloy powder particles correspond to the crown-like protrusions on the "coronavirus" sphere); the specific shape of the protruding short dendrites is shown in the embodiment; although such insufficiently spherical protruding short dendrites have a certain impact on the sphericity of the ferroalloy powder particles, since the sphericity of the ferroalloy powder particles to which the protruding short dendrites attach is itself very high, even if some spherical or near-spherical ferroalloy powder particles contain certain protruding short dendrite features, such particles are still spherical or near-spherical ferroalloy powder particles with high sphericity.

[0127] Furthermore, the iron alloy powder particles are mainly spherical or near-spherical in shape; in addition, the iron alloy powder particles also contain a small amount of typical dendritic powder particles.

[0128] The ferroalloy powder particles are mainly spherical or near-spherical in shape, and some of the spherical or near-spherical ferroalloy powder particles contain certain dendritic features; at the same time, the ferroalloy powder particles also contain a small number of typical dendritic particles. The presence of these two dendritic features is a unique characteristic of the ferroalloy powder particles obtained through this application.

[0129] Further, the particle size of the ferroalloy powder particles is 5nm to 40μm; further, the particle size of the ferroalloy powder particles is 5nm to 30μm; further, the particle size of the ferroalloy powder particles is 5nm to 20μm; further, the particle size of the ferroalloy powder particles is 5nm to 10μm.

[0130] Furthermore, the particle size of the iron alloy powder is 100 nm to 50 μm;

[0131] Furthermore, the particle size of the iron alloy powder is 250 nm to 50 μm;

[0132] Furthermore, the particle size of the iron alloy powder is 500 nm to 50 μm;

[0133] Furthermore, the particle size of the iron alloy powder is 5nm to 100nm;

[0134] Furthermore, the particle size of the iron alloy powder is 5 nm to 50 nm;

[0135] Furthermore, when the average particle size of the ferroalloy powder is greater than 0.25 μm, the shape of the powder particles is still mainly spherical;

[0136] Furthermore, when the average particle size of the ferroalloy powder is greater than 0.5 μm, the shape of the powder particles is still mainly spherical;

[0137] Furthermore, when the average particle size of the ferroalloy powder is greater than 1 μm, the shape of the powder particles is still mainly spherical.

[0138] Furthermore, when the average particle size of the ferroalloy powder is greater than 3 μm, the shape of the powder particles is still mainly spherical.

[0139] Furthermore, the number of single crystal particles in the iron alloy powder particles accounts for no less than 60% of the total number of particles.

[0140] Among all rare earth elements, La is a special case, and among all iron-group elements Fe, Co, and Ni, Fe is also a special case. This is because, among the various combinations of iron-group elements and rare earth elements, only La-Fe alloys do not form intermetallic compounds, and the two elements do not show significant mutual solid solubility. Utilizing this characteristic is the basis for the formation of a La-rich matrix phase and a Fe-rich dispersed particle phase in the solidification structure of the initial alloy solid in this invention. Based on this, by selecting and controlling the content of T-type, M-type, and D-type elements, the original dendritic particle phase during the solidification process of the initial alloy melt is altered to change its growth pattern into a spherical or near-spherical particle phase. This yields ultrafine spherical iron alloy powder with a composition largely similar to commercial alloys, but with significantly different particle sizes (e.g., smaller particle size, lower oxygen impurities, and solid solution of rare earth elements). This is the key to the inventiveness of this application. Without selecting and controlling the content of T-type, M-type, and D-type elements, and without discovering and utilizing the spheroidizing effect of T-type elements, simply using La-Fe alloys can only produce dendritic, easily corroded Fe dendritic powders without particle flowability and low density in powder metallurgy, thus greatly limiting its application value.

[0141] In practice, as a rare earth element raw material, La can also contain small amounts of other rare earth elements. As long as the atomic percentage of other rare earth elements does not exceed 25% of the La raw material content, it has little impact on the law. These other rare earth elements are dissolved in La, replacing part of the function of La. In this case, La in this invention refers to La rare earth and other rare earth elements.

[0142] Further, the composition of the initial alloy melt in Step 1 further includes non-metallic impurity elements, and the non-metallic impurity elements include at least one of O, N, H, P, S, and Cl; the atomic percentage content of the non-metallic impurity elements in the initial alloy melt is greater than 0 and less than 10%; during the formation process of the Fe-rich dispersed particle phase in Step 2, the non-metallic impurity elements are enriched in the La-rich matrix phase, thereby purifying the Fe-rich dispersed particle phase, that is, the atomic percentage content of the non-metallic impurity elements in the Fe-rich dispersed particle phase is lower than the atomic percentage content of the non-metallic impurity elements in the initial alloy melt; and in the Fe-rich dispersed particle phase, the atomic percentage content of the non-metallic impurity elements is lower than 1.5%; and in Step 3, the content of non-metallic impurity elements in the spherical or near-spherical ferroalloy powder particles is also lower than that in the initial alloy melt.

[0143] Further, the obtained ferroalloy powder particles are subjected to particle size classification. For example, powders above 10 μm, powders of 1 μm - 5 μm, powders of 5 μm - 10 μm, powders below μm, etc. are separated to obtain spherical ferroalloy powder materials with different particle sizes, which can be applied to different fields.

[0144] On the other hand, the present invention also relates to a spherical ferroalloy powder material, which is characterized in that it is prepared by the preparation method of the spherical ferroalloy powder material described in its one aspect, and the specific characteristics are as described in its one aspect;

[0145] Some characteristics of the spherical ferroalloy powder material include: the main component of the spherical ferroalloy powder material is Fe y2 T z2 M a2 D b2 La x2 ; where, 50% ≤ y2 ≤ 98%, 0.2% ≤ z2 < 50%, 0% ≤ a2 ≤ 30%, 0% ≤ b < 35%, 0 < x2 ≤ 5%; the shape of the ferroalloy powder particles is mainly spherical or near-spherical, and some spherical or near-spherical ferroalloy powder particles have certain dendritic characteristics; the particle size of the ferroalloy powder particles is 5 nm to 50 μm. <00009>

[0146] Further, the sphericity of the spherical or near-spherical ferroalloy powder particles exceeds 65%;

[0147] Further, the volume percentage content of the spherical or near-spherical ferroalloy powder particles in all ferroalloy powders is greater than 25%;

[0148] Further, in the spherical or near-spherical ferroalloy powder particles, the total atomic percentage content of O, N, H, P, S, and Cl elements is lower than 1.5%.

[0149] Further, T contains at least one of Cr and V, M contains at least one of Al, Ni, Co, and Si, and D contains at least one of Mo, W, and Ti; x1, a1, x2, y2, z2, a2, and b2 respectively represent the atomic percentage contents of the corresponding constituent elements.

[0150] Thirdly, the present invention also relates to a method for preparing a spherical iron-chromium-silicon powder material with a high silicon content, which is characterized in that the spherical iron alloy powder material with Fe-Cr as the main constituent elements prepared in steps 1 to 3 of one aspect thereof or the spherical iron alloy powder material with Fe-Cr-Si as the main constituent elements and a low Si content is subjected to Si infiltration treatment, thereby obtaining a spherical powder material with Fe-Cr-Si as the main composition and a high Si content.

[0151] Since the solid solubility of Si atoms in the Fe-Cr-Si spherical iron alloy powder material directly obtained through steps 1 to 3 of one aspect thereof is difficult to exceed \(8\%\), and this can only be achieved when a large amount of Si is contained in the initial alloy melt, while the atomic percentage of Si in the actual commercial Fe-Cr-Si magnetic iron alloy powder generally exceeds \(8\%\). In order to obtain a higher Si content, the spherical iron alloy powder material with Fe-Cr as the main constituent elements prepared in steps 1 to 3 of one aspect thereof or the spherical iron alloy powder material with Fe-Cr-Si as the main constituent elements and a low Si content can be subjected to Si infiltration treatment to obtain a spherical Fe-Cr-Si powder material with a high Si content.

[0152] Further, the Si infiltration treatment includes at least one of solid Si infiltration, liquid Si infiltration, and gas Si infiltration processes.

[0153] Further, the silicon source for solid Si infiltration includes at least one of Si or a silicon-rich alloy; the silicon source for liquid Si infiltration is mainly a Si-containing liquid; the silicon source for gas Si infiltration is mainly a Si-containing gas;

[0154] Further, the treatment temperature for solid Si infiltration is \( \text{400}^{\circ}\text{C} \) to \( \text{1200}^{\circ}\text{C} \).

[0155] Further, the present invention also provides an improved process for Si infiltration:

[0156] Further, according to steps 1 and 2 of one aspect thereof, the initial alloy solid described in step 2 of one aspect thereof is prepared; wherein, T contains Cr, M contains Si, and \( 0 \lt a \leq 40\% \); the average composition of the matrix phase is mainly La x1 Si a1 ; the composition of the dispersed particle phase is mainly Fe with a low Si content y2 Cr z2 Si a2 D b2 Lax2 ; The La x1 Si a1 in the matrix phase is combined with La in the form of intermetallic compounds; 0 < a2 ≤ 8%; The initial alloy solid La x1 Si a1 in the matrix phase is removed through dealloying reaction, while retaining the original La x1 Si a1 in the matrix phase, obtaining nanoporous Si and the Fe y2 Cr z2 Si a2 D b2 La x2 particle composite powder; The nanoporous Si can be used as the Si source for Si infiltration of the Fe y2 Cr z2 Si a2 D b2 La x2 powder.

[0157] Furthermore, the nanoporous Si is used as the Si source for Si infiltration of the Fe with low Si content y2 Cr z2 Si a2 D b2 La x2 particles, and a spherical Fe-Cr-Si powder material with high Si content is obtained;

[0158] Furthermore, the methods of solid-state Si infiltration of the nanoporous Si and the Fe y2 Cr z2 Si a2 D b2 La x2 particles include: directly performing solid-state Si infiltration, or first compacting it and then performing solid-state Si infiltration operation;

[0159] Furthermore, the treatment temperature of solid-state Si infiltration is 400°C to 1200°C;

[0160] Furthermore, the composition of the obtained spherical Fe-Cr-Si powder material with high Si content is mainly Fe y3 Cr z3 Si a3 D b3 La x3 ; where x3, y3, z3, a3, b3 respectively represent the atomic percentage contents of the corresponding constituent elements, and 0 < y3 < y2, 0 < z3 < z2, 0 < a2 < a3, 0 ≤ b3 ≤ b2, 0 < x3 < x2.

[0161] Furthermore, 5% < a3; furthermore, 10% < a3;

[0162] Furthermore, for the spherical Fe-Cr-Si powder material with a high Si content, except that the Si content is increased by the siliconizing treatment, which also leads to an automatic adjustment of the alloy composition, the morphology and size of the powder material still basically remain the same as before the siliconizing treatment.

[0163] Furthermore, since Si is brittle, after the siliconizing treatment, the spherical Fe-Cr-Si powder material with a high Si content after the siliconizing treatment can be pulverized back into loose granular form through dispersion and crushing techniques. Even if there may be residual uncompletely infiltrated nano-porous Si on the surface of the spherical Fe-Cr-Si powder with a high Si content, it is sometimes a beneficial existence.

[0164] Furthermore, the obtained spherical Fe-Cr-Si powder particles with a high Si content are subjected to particle size classification, for example, separating powders above, between, between, and below 10 μm, etc., to obtain spherical Fe-Cr-Si powder materials with different particle sizes, which can be applied to different fields.

[0165] Fourthly, the present invention also relates to a spherical iron-chromium-silicon powder material with a high silicon content, which is characterized in that it is prepared by the preparation method of the spherical iron-chromium-silicon powder material with a high silicon content described in its third aspect, and its specific characteristics are as described in its third aspect.

[0166] Fifthly, the present invention also relates to a composite powder of nano-porous Si and spherical Fe-Cr-Si particles, which is characterized in that nano-porous Si and Fe y2 Cr z2 Si a2 D b2 La x2 particles with a low Si content are prepared by the siliconizing improvement process described in its third aspect to obtain a composite powder of nano-porous Si and spherical Fe-Cr-Si particles; its characteristics are as described in the siliconizing improvement process of its third aspect.

[0167] Sixthly, the present invention also relates to a preparation method of a high-nickel-content iron-chromium-nickel powder metallurgy product, which is characterized by including the following steps:

[0168] Step 1, according to Step 1 and Step 2 of its first aspect, prepare the initial alloy solid described in Step 2 of its first aspect; wherein, T contains Cr, M contains Ni, 0 < a ≤ 40%; the average composition of the matrix phase is mainly La x1 Ni a1 ; the composition of the dispersed particle phase is mainly Fe with a low Ni content y2 Crz2 Ni a2 D b2 La x2 The La x1 Ni a1 In the matrix phase, Ni is bonded to La via intermetallic compounds; 0 <a2≤12%;

[0169] Step 2, the initial alloy solid La is reacted with a dilute acid solution. x1 Ni a1 La in the matrix phase is removed via a dealloying reaction, while preserving the original La content. x1 Ni a1 Most of the Ni in the matrix phase is not removed by the reaction, resulting in nanoporous Ni and low-Ni-content Fe. y2 Cr z2 Ni a2 D b2 La x2 Composite powders of particles;

[0170] Step 3, mix nanoporous Ni with the low-Ni content Fe y2 Cr z2 Ni a2 D b2 La x2 The composite powder particles are pressed into shape and then heat-treated and sintered to obtain high-Ni content iron-chromium-nickel powder metallurgy products, whose main component is Fe. y3 Cr z3 Ni a3 D b3 La x3 Where x3, y3, z3, a3, and b3 represent the atomic percentage content of the corresponding constituent elements, and 0 <y3<y2,0<z3<z2,0<a2<a3,0≤b3≤b2,0<x3<x2。

[0171] On the one hand, during the initial solidification of the alloy melt, due to the high Ni content in the matrix, the atomic percentage of Ni dissolved in the Fe-rich dispersed particles generally does not exceed 12%. Generally, the Ni content in Fe-Ni based superalloys needs to reach 30%-40%. Therefore, this method increases the Ni content in low-Ni Fe alloys. y2 Cr z2 Ni a2 D b2 La x2 Adjusting the Ni content in the particles can yield high-Ni iron-chromium-nickel powder metallurgy products, suitable for high-temperature alloy applications.

[0172] In step 1,

[0173] Furthermore, 18%≤x≤85%, 10%≤y≤81.8%, 5%≤a≤40%; 2%≤z≤35%, 0≤b≤15%; 45%≤x1≤100%, 0%≤a1≤55%, 50%≤y2≤85%, 4%≤z2<50%;

[0174] Furthermore, the La x1 Ni a1 The way in which Ni in the matrix phase is bonded to La through intermetallic compounds includes at least one of La3Ni intermetallic compound, La7Ni3 intermetallic compound, and LaNi intermetallic compound;

[0175] In step 2,

[0176] Although both La and Ni react with acids, rare earth element La exhibits higher reactivity, and intermetallic compounds generally contain higher levels of La. Therefore, by adjusting the type and concentration of dilute acid, La can be removed through a dealloying reaction. While a small amount of Ni inevitably corrodes and dissolves, most of the Ni can be retained by transforming into nanoporous Ni through the dealloying reaction. Meanwhile, Fe with low Ni content... y2 Cr z2 Ni a2 D b2 La x2 The particulate phase contains Cr, which is corrosion-resistant and can be completely preserved;

[0177] Furthermore, the size of the nanoporous Ni ligatures is less than 200 nm;

[0178] Because the nanoporous Ni is significantly fragmented after the dealloying reaction in this application and cannot be retained as a complete matrix, the obtained nanoporous Ni and the low-Ni content Fe... y2 Cr z2 Ni a2 D b2 La x2 In composite powders with low Ni content, Fe y2 Cr z2 Ni a2 D b2 La x2 The particles have been freed up, but they are mixed with nanoporous Ni fragments.

[0179] In step 3

[0180] Furthermore, the pressing and heat treatment sintering can be performed sequentially or simultaneously; simultaneous performance is called hot pressing sintering.

[0181] Furthermore, the heat treatment sintering temperature is lower than that of low Ni content Fe. y2 Crz2 Ni a2 D b2 La x2 Melting point of the particles;

[0182] Further, the heat treatment sintering temperature is 400°C to 1400°C;

[0183] Further, the heat treatment sintering temperature is 400°C to 1100°C;

[0184] Further, the heat treatment sintering temperature is 400°C to 900°C;

[0185] Further, during the heat treatment sintering process, the nanoporous Ni enters the Fe with low Ni content y2 Cr z2 Ni a2 D b2 La x2 particles and dissolves in them solidly, increasing its nickel content;

[0186] Further, 10% < a3; Further, 15% < a3; Further, 20% < a3; Further, 30% < a3.

[0187] In the seventh aspect, the present invention also relates to a high-nickel-content iron-chromium-nickel powder metallurgy product, characterized in that it is prepared by the preparation method of the high-nickel-content iron-chromium-nickel powder metallurgy product described in its sixth aspect; its characteristics are as described in its sixth aspect.

[0188] In the eighth aspect, the present invention also relates to a composite powder of nanoporous Ni and iron-chromium-nickel particles with low Ni content, characterized in that it is prepared by steps 1 and 2 of the method described in its sixth aspect; its characteristics are as described in its sixth aspect.

[0189] In the ninth aspect, the present invention also relates to the application of the spherical iron alloy powder material described in its second aspect in any one of the following fields, and the application fields include ordinary powder metallurgy, metal injection molding (MIM), 3D printing, magnetic materials, heat-resistant materials, superalloys, coatings, and wave-absorbing materials.

[0190] In terms of ordinary powder metallurgy, both the spherical iron alloy powder material described in the first aspect and the second aspect of the present invention can be used in the field of ordinary powder metallurgy. That is, the powder is pressed into a blank, and then a bulk powder metallurgy product of the corresponding composition is directly sintered, or the powder is compounded with other powders, and then pressed into a blank and sintered to produce a bulk powder metallurgy product of the corresponding composite composition. The other powders include at least one of metal powders, alloy powders, oxide powders, carbide powders, nitride powders, carbon powders, and ceramic powders of other compositions;

[0191] In metal injection molding (MIM), the theoretically optimal particle size for powder materials is 0.5 μm to 10 μm. However, due to current technological limitations, the particle size of powder materials used in MIM is generally greater than 10 μm, and even exceeds 50 μm. The method described in this invention is very suitable for preparing powders with a particle size of 0.5 μm to 10 μm, and the finer the powder, the easier it is to prepare. Therefore, the ferroalloy powder materials involved in one aspect and the other aspect of this invention are very suitable for the field of metal injection molding (MIM). The difference between MIM technology and ordinary powder metallurgy technology is that in MIM, the powder and organic binder are used together to form a preform. After removing the organic binder, sintering is performed to obtain the finished product. Due to the removal of the binder, the volume of the sintered product shrinks by 10% to 20% relative to the preform.

[0192] In 3D printing, fine powder spreading requires spherical powder particles with a diameter of approximately 15μm to 53μm. In this invention, when the content of dissolved elements in Fe is high, and the contents of Cr and V are also high, spherical ferroalloy powder within this particle size range can be obtained. Furthermore, through further sieving, powder particles within this size range can be concentrated. Therefore, the spherical ferroalloy powder materials described in one and both aspects of this invention can also be used in the field of 3D printing under certain circumstances.

[0193] In the field of magnetic materials, the spherical iron alloy powder materials with some components involved in one and two aspects of this invention can also be used in soft magnetic materials or hard magnetic materials (permanent magnets). For example, powder materials with Fe-Cr or Fe-Cr-Si as the main element composition can be used in soft magnetic materials (such as magnetic powder cores), while powder materials with Fe-Cr-Co as the main element composition can be used in hard magnetic materials.

[0194] Furthermore, when the powder materials whose main elemental composition is Fe-Cr or Fe-Cr-Si involved in this invention are used in soft magnetic materials, they are used as magnetic powder cores.

[0195] Furthermore, the magnetic powder core is formed by coating an insulating coating material with a powder material whose main elemental composition is Fe-Cr or Fe-Cr-Si, and then pressing it at a certain temperature; further, the pressing temperature is from room temperature to 800°C.

[0196] Furthermore, the weight percentage of the insulating coating material in the magnetic powder core is greater than 0.1% and less than 15%;

[0197] Furthermore, the insulating coating material includes resin; preferably, the insulating coating material includes at least one of silicone resin, phenolic resin, epoxy resin, polypropylene, and nylon.

[0198] In the field of heat-resistant materials, the spherical iron alloy powder materials containing high-melting-point elements such as V, W, Mo, and Ti, or spherical iron alloy powder materials containing Al that can form an alumina heat-resistant protective layer at high temperatures, such as powder materials or powder metallurgy products and MIM products prepared from spherical iron alloy powder materials with the main elemental composition of Fe-Cr-Al or Fe-Cr-Al-(V / W / Mo / Ti), can greatly improve their heat resistance and can be used in heat-resistant materials. In industrial applications, such as heating furnaces, heat exchangers, fiber burners, and hot gas filtration systems, especially as metal honeycomb carriers for exhaust gas catalysts, iron-chromium-aluminum powder metallurgy alloy products have more obvious advantages than traditional ceramic honeycomb carriers.

[0199] In the field of high-temperature alloys, the spherical iron alloy powder materials containing high-melting-point elements such as V, W, Mo, and Ti involved in one and two aspects of this invention, such as products prepared from spherical iron alloy powder materials with a main elemental composition of Fe-Cr-Ni-(V / W / Mo / Ti), exhibit excellent high-temperature resistance. When the composition of the spherical iron alloy powder materials containing high-melting-point elements such as V, W, Mo, and Ti involved in one and two aspects of this invention is the same as or close to the composition of high-temperature alloys, it can be used in the field of high-temperature alloys.

[0200] In the field of coatings, the spherical iron alloy powder material involved in one aspect and the other aspect of this invention can be used as a key component in the field of coatings, including thermal spray coatings, resin-based coatings, and magnetic shielding coatings.

[0201] In terms of microwave absorbing materials, the spherical iron alloy powder material involved in one aspect and the other aspect of this invention can be used as a magnetic metal powder in the field of microwave absorbing materials.

[0202] In another aspect, the present invention also relates to the application of the spherical iron alloy powder material described in the second aspect in the field of electrothermal materials, and the main components of the spherical iron alloy powder material include Fe-Cr-Al.

[0203] In the field of electrothermal materials, the powder materials with Fe-Cr-Al and Fe-Cr-Al-(V / W / Mo / Ti) as their main elemental composition involved in one and two aspects of this invention, after being processed into finished products using powder metallurgy technology, are excellent electrothermal materials. For example, iron-chromium-aluminum electrothermal alloy elements prepared from the powder materials with the aforementioned Fe-Cr-Al and Fe-Cr-Al-(V / W / Mo / Ti) main elemental composition can reach operating temperatures above 1400℃. Because the alloy with the Fe-Cr-Al main elemental composition has a high aluminum content, it possesses a high resistivity, reaching a maximum value of 1.6 μΩ·m. This high resistivity effectively converts electrical energy into heat energy; simultaneously, the iron-chromium-aluminum alloy is inexpensive, costing only 20% to 25% of nickel-chromium alloys, which facilitates its widespread use. Furthermore, it possesses good heat resistance, low specific gravity, and excellent resistance to high-temperature oxidation, making it widely used in various aspects of production and daily life. In everyday life, heating elements made from iron-chromium-aluminum powder metallurgy alloys include heating wires, heating rods, cooking plates, radiators, toasters, microwave ovens, water heaters, washing machines, boilers, and precision resistive elements in automobiles.

[0204] In its eleventh aspect, the present invention also relates to the application of the high-silicon-content spherical iron-chromium-silicon powder material described in its fourth aspect in magnetic materials;

[0205] Furthermore, when the high-silicon-content spherical iron-chromium-silicon powder material involved in the four aspects of the present invention is used in soft magnetic materials, it includes applications as magnetic powder cores.

[0206] Furthermore, the magnetic powder core is formed by coating the high-silicon-content spherical iron-chromium-silicon powder material with an insulating coating material, and then pressing it at a certain temperature; further, the pressing temperature is from room temperature to 800°C.

[0207] Furthermore, the weight percentage of the insulating coating material in the magnetic powder core is greater than 0.1% and less than 15%;

[0208] Furthermore, the insulating coating material includes resin; preferably, the insulating coating material includes at least one of silicone resin, phenolic resin, epoxy resin, polypropylene, and nylon.

[0209] In its twelfth aspect, the present invention also relates to the application of the high-nickel content iron-chromium-nickel powder metallurgy products described in its seventh aspect in high-temperature alloys.

[0210] High-temperature alloys mainly include nickel-based, iron-based, and nickel-iron-based high-temperature alloys. When the composition of the high-nickel content iron-chromium-nickel powder metallurgy product described in the seventh aspect of this invention is the same as or close to the composition of the high-temperature alloy, it can be used in the field of high-temperature alloys.

[0211] In the thirteenth aspect, the present invention also relates to an alloy solid, which is characterized in that it is prepared by the preparation method of the initial alloy solid described in Step 1 and Step 2 of one of its aspects, and the specific features are as detailed in one of its aspects.

[0212] Its specific features include being prepared by including the following steps:

[0213] Step 1: Select the initial alloy raw materials, melt the initial alloy raw materials according to the initial alloy composition ratio to obtain a uniform initial alloy melt; the main components of the initial alloy melt are La x Fe y T z M a D b , where T includes at least one of Cr and V, M includes at least one of Al, Ni, Co, and Si, D includes at least one of Mo, W, and Ti, x, y, z, a, and b respectively represent the atomic percentage contents of the corresponding constituent elements, and 18% ≤ x ≤ 95.8%, 4% ≤ y ≤ 81.8%, 0.1% ≤ z ≤ 35%, 0 ≤ a ≤ 40%, 0 ≤ b ≤ 15%;

[0214] Step 2: Solidify the initial alloy melt into an initial alloy solid by rapid solidification technology; the solidification structure of the initial alloy solid includes a matrix phase and a dispersed particle phase; the melting point of the matrix phase is lower than that of the dispersed particle phase, and the dispersed particle phase is coated in the matrix phase; the volume percentage of the matrix phase in the solidification structure is not less than 40%; the average composition of the matrix phase is mainly La x1 M a1 ; the composition of the dispersed particle phase is mainly Fe y2 T z2 M a2 D b2 La x2 , where x1, a1, x2, y2, z2, a2, and b2 respectively represent the atomic percentage contents of the corresponding constituent elements, and 45% ≤ x1 ≤ 100%, 0% ≤ a1 ≤ 55%, 50% ≤ y2 ≤ 98%, 0.2% ≤ z2 < 50%, 0% ≤ a2 ≤ 30%, 0% ≤ b2 ≤ 35%, 0 < x2 ≤ 5%; the dispersed particle phase includes a considerable content of spherical or near-spherical dispersed particle phases, and some spherical or near-spherical dispersed particle phases have certain dendritic characteristics; the particle size of the dispersed particle phase is 5 nm to 50 μm.

[0215] Further, the composition of the initial alloy melt in step one further includes non-metallic impurity elements, and the non-metallic impurity elements include at least one of O, N, H, P, S, and Cl; the atomic percentage content of the non-metallic impurity elements in the initial alloy melt is greater than 0 and less than 10%; during the formation process of the Fe-rich dispersed particle phase in step two, the non-metallic impurity elements are enriched in the La-rich matrix phase, thereby purifying the Fe-rich dispersed particle phase, that is, the atomic percentage content of the non-metallic impurity elements in the Fe-rich dispersed particle phase is lower than the atomic percentage content of the non-metallic impurity elements in the initial alloy melt; and in the Fe-rich dispersed particle phase, the atomic percentage content of the non-metallic impurity elements is lower than 1.5%.

[0216] In a fourteenth aspect, the present invention also relates to the application of the spherical ferroalloy powder material described in its second aspect in the field of magnetic fluids.

[0217] The characteristics of the spherical ferroalloy powder material are as described in its first aspect and second aspect; some characteristics of the spherical ferroalloy powder material include: the main component of the spherical ferroalloy powder material is Fe y2 T z2 M a2 D b2 La x2 ; wherein, 50% ≤ y2 ≤ 98%, 0.2% ≤ z2 < 50%, 0% ≤ a2 ≤ 30%, 0% ≤ b2 ≤ 35%, 0 < x2 ≤ 5%; the shape of the ferroalloy powder particles is mainly spherical or near-spherical, and some spherical or near-spherical ferroalloy powder particles have certain dendritic characteristics; the particle size of the ferroalloy powder particles is 5 nm to 100 nm; T includes at least one of Cr and V, M includes at least one of Al, Ni, Co, and Si, D includes at least one of Mo, W, and Ti; x1, a1, x2, y2, z2, a2, b2 respectively represent the atomic percentage content of the corresponding constituent elements.

[0218] Preferably, the particle size of the spherical ferroalloy powder particles is 5 nm to 50 nm;

[0219] More preferably, the particle size of the spherical ferroalloy powder particles is 5 nm to 25 nm;

[0220] Further, 50% ≤ y2 ≤ 95%;

[0221] Further, 1% ≤ z2 + b2 < 50%; further, 2% ≤ z2 + b2 < 50%; further, 3% ≤ z2 + b2 < 50%;

[0222] Further, 1% ≤ z2 < 50%; further, 2% ≤ z2 < 50%; further, 3% ≤ z2 < 50%;

[0223] In the field of magnetic fluids, the spherical ferroalloy powder materials involved in one aspect and the second aspect of the present invention can be used in the field of magnetic fluids; specifically, it includes: mixing the spherical ferroalloy powder, carrier liquid and surfactant evenly to obtain a magnetic fluid.

[0224] Furthermore, the carrier liquid includes at least one of water, ethanol, carbohydrates, fats, diesters, mercury.

[0225] Furthermore, the surfactant includes at least one of oleic acid, polyvinylpyrrolidone, polyethylene glycol, ethylene glycol, sodium dodecylbenzenesulfonate.

[0226] As the magnetic solid particles of magnetic fluids, it is generally required that their particle size is nanoscale; Fe is one of the best magnetic materials, but when nano-Fe particles are used as the magnetic solid particles of magnetic fluids, due to the easy oxidation of nano-Fe particles, their performance is unstable and it is difficult to be well applied. This application solves this problem well. When the prepared spherical Fe alloy powder particles contain a certain amount of corrosion-resistant Cr, V, Mo, W, Ti elements in solid solution, it can not only make the spheroidization more obvious, but also significantly improve the corrosion resistance of nano-Fe alloy powder particles. This improvement in corrosion resistance makes it possible to remove the matrix in the alloy solid by acid etching solution while retaining the nano-Fe alloy powder particles; at the same time, it also makes it possible to use the corrosion-resistant nano-Fe alloy powder particles as the magnetic solid particles of magnetic fluids.

[0227] In its fifteenth aspect, the present invention also relates to a coronavirus-shaped spherical ferroalloy powder particle, and its characteristics include: the main component of the coronavirus-shaped spherical ferroalloy powder particle is Fe y2 T z2 M a2 D b2 La x2 ; where 50% ≤ y2 ≤ 98%, 0.2% ≤ z2 < 50%, 0% ≤ a2 ≤ 30%, 0% ≤ b2 ≤ 35%, 0 < x2 ≤ 5%; T includes at least one of Cr, V, M includes at least one of Al, Ni, Co, Si, D includes at least one of Mo, W, Ti, La is rare earth La, and La mainly exists in solid solution in the main component Fe y2 T z2 M a2 D b2 La x2In the coronavirus-like spherical ferroalloy particles; x1, a1, x2, y2, z2, a2, and b2 represent the atomic percentage content of the corresponding constituent elements; the coronavirus-like spherical ferroalloy powder particles include a main body and an appendage part; wherein, the main body is a spherical or near-spherical sphere, and the appendage part consists of multiple protrusions grown in situ on the surface of the sphere of the main body; the spherical ferroalloy powder particles have a coronavirus-like shape, and the multiple protrusions of its appendage part correspond to multiple crown-shaped protrusions of the coronavirus shape; the diameter of the sphere of the main body of the coronavirus-like spherical ferroalloy powder particles is 20 nm to 50 μm, and the height of the protrusions of its appendage part is less than 0.3 times the diameter of the sphere of the main body.

[0228] Furthermore, the number of protrusions on any single coronavirus-shaped spherical ferroalloy powder particle exceeds 5;

[0229] Furthermore, the number of protrusions on any single coronavirus-shaped spherical ferroalloy powder particle exceeds 10;

[0230] The diameter of the main body of the coronavirus-like spherical ferroalloy powder particles is 50 nm to 15 μm.

[0231] The diameter of the main body of the coronavirus-like spherical ferroalloy powder particles is 200 nm to 10 μm.

[0232] The diameter of the main body of the coronavirus-like spherical ferroalloy powder particles is 200 nm to 5 μm.

[0233] Furthermore, any single protrusion of the appendage portion is composed of no more than one grain, and the crystal structure and crystal plane orientation of the grain and the crystal structure and crystal plane orientation of the sphere portion connected to it are the same.

[0234] Furthermore, both the main body and the attached body of the coronavirus-like spherical ferroalloy powder particles belong to a large single crystal.

[0235] It is understandable that, since the crystal structure and crystal plane orientation at the junction of the main body and the attached body are consistent with those of both the main body and the attached body, it can be considered that the spherical main body and the multiple protruding attached body of the coronavirus-like spherical iron alloy powder particles belong to a large single crystal.

[0236] Furthermore, the height of the protrusion in the appendage is less than 0.2 times the diameter of the sphere in the main body;

[0237] Furthermore, the protrusion is a dendritic protrusion, that is, the protrusion is the preferential growth point for the transition from spherical particles to dendritic particles; or it can be understood as: after the spherical particles grow to a certain stage, preferential growth points appear in certain parts of the spherical surface, and then continue to grow preferentially into protrusions according to the original crystal structure and crystal orientation of the growth point.

[0238] Furthermore, the diameter of the protruding appendage is less than 0.25 times the diameter of the main sphere of the coronavirus-like spherical ferroalloy powder particle;

[0239] Furthermore, the morphological characteristics of the coronavirus-like spherical ferroalloy powder particles can be referred to in the embodiments. Figure 3 , Figure 11 , Figure 12 , Figure 15 The shape of the coronavirus-like spherical particles shown;

[0240] Furthermore, the coronavirus-like spherical ferroalloy powder material is prepared by one aspect of the method described herein.

[0241] The beneficial effects of this invention are mainly reflected in the following aspects:

[0242] 1) By adding T-type elements, the precipitation and subsequent separation of corrosion-resistant and oxidation-resistant spherical or near-spherical Fe-rich dispersed particles in a La-rich matrix phase were achieved. The selection of T-type elements has several advantages: T-type elements are completely miscible with Fe, allowing for their addition in large quantities; like Fe, T-type elements do not form any intermetallic compounds with La, and they almost never enter the La-rich phase, only the Fe-rich dispersed particle phase; the solid solution presence of T-type elements makes the Fe-rich dispersed particle phase tend to spheroidize, which is key to preparing spherical or near-spherical Fe alloy powders; T-type elements are completely miscible with D-type elements, and when the solid solubility of D-type elements in Fe is 10%-20%, the presence of T-type elements allows for easier solid solution of more D-type elements in the Fe-rich dispersed particle phase; T-type elements Cr and V are both corrosion-resistant elements in Fe alloys, and their inclusion in the Fe-rich dispersed particle phase significantly improves its corrosion and oxidation resistance, making it possible for the Fe-rich dispersed particle phase to separate from the La-rich matrix phase through acid corrosion and oxidation-pulverization separation. Otherwise, the pure Fe phase is also prone to reaction with acid and oxidation, especially when the particle size is relatively fine.

[0243] 2) Beneficial rare earth elements are directly dissolved in spherical or near-spherical Fe alloy powder. Adding rare earth elements to ferroalloys has a positive effect on material performance. For example, adding a small amount of rare earth elements to Fe-Cr-Al electrothermal alloys improves their performance. Industrially, when rare earth elements are added to Fe alloys, they are easily oxidized. When added in small amounts, they generally combine with impurities such as oxygen in the alloy, existing non-uniformly as oxide particles, resulting in limited performance improvement. However, the initial alloy melt in this application contains a relatively high amount of La (La-rich matrix phase volume percentage higher than 40%). Therefore, oxygen in the alloy melt mainly exists in the La-rich matrix phase, while a small amount of La is dissolved in the spherical or near-spherical Fe alloy powder. This La is uniformly dissolved in the Fe alloy powder in an atomic state, representing a strictly alloyed rare earth element with a more positive effect on material performance. The presence of dissolved rare earth element (La) in Fe alloy powder is one of the key characteristics of the iron alloy powder material prepared in this invention.

[0244] 3) The preparation of ultrafine ferroalloy powder materials mainly composed of spherical or near-spherical particles has been achieved. Spherical or near-spherical Fe alloy particles are key raw materials for applications such as powder metallurgy, powder spraying, powder coating, metal injection molding (MIM), and 3D printing due to their excellent flowability, uniformity, and dense powder packing. Currently, spherical Fe alloy powder materials cannot be prepared by chemical methods and can only be prepared mainly by atomization, which utilizes high-speed fluid to directly break up liquid metal or alloys to obtain metal powder. However, due to the limitation of atomization capacity, it is generally only suitable for the preparation of spherical Fe alloy powders with a particle size of 10μm to 150μm. For spherical Fe alloy powder materials smaller than 10μm, especially around 1μm, atomization is difficult or impossible to prepare. The technical solution provided in this application realizes the preparation of ultrafine spherical ferroalloy powder materials with particle sizes ranging from nanometers to several micrometers, and can obtain such ultrafine spherical ferroalloy powder materials on a large scale at low cost, which has significant application value.

[0245] 4) The prepared spherical or near-spherical ferroalloy powder particles contain protruding short dendrites. For powder metallurgy, especially metal injection molding (MIM), the strength of the blank is a key factor in normal production. For example, in metal injection molding (MIM), the blank is formed by pressing metal powder with an organic binder, and then removing the organic binder. The MIM blank only achieves high strength after sintering and shrinkage. Before sintering and after removing the organic binder, the MIM blank needs mechanical bonding between particles to maintain its shape. If the metal powder consists entirely of ideal spherical particles, the mechanical-frictional bonding between these particles is extremely poor, easily leading to the blank falling apart. In this application, some spherical or near-spherical ferroalloy powder particles contain protruding short dendrites. This feature has little impact on the sphericity of the particles, but it can greatly enhance the mechanical bonding or frictional force between particles, thereby increasing the strength of the blank. If all particles have this protruding short dendrite feature, it will affect the powder flowability of the spherical particles. The iron alloy powder particles prepared in this application exhibit this protruding short dendrite feature only on the surface of some of the prepared spherical or near-spherical iron alloy powder particles. Therefore, the protruding short dendrites on some spherical iron alloy powder particles are another key feature of the Fe alloy powder prepared by this invention.

[0246] 5) During the formation of the Fe-rich dispersed particle phase, the Fe-rich dispersed particle phase was simultaneously purified. If the initial alloy is prepared from raw materials containing impurity elements such as O, N, H, P, S, and Cl with low purity, or if these impurities are introduced into the melt during the initial alloy smelting process, it will not affect the final obtaining of a Fe-rich dispersed particle phase with low impurity content. This allows for the further acquisition of spherical iron alloy powder materials with low impurity content. This is because most of the impurity elements in the raw materials, or those introduced during smelting, are captured by the La-rich matrix phase during the solidification of the initial alloy melt and subsequently enter the matrix phase, thus purifying the Fe-rich dispersed particle phase.

[0247] 6) Ferroalloy powder materials mainly composed of single-crystal particles can be obtained. Compared with polycrystalline powder, single-crystal powder can achieve many significant and beneficial effects. During the initial solidification process of the alloy melt, each intermolecular particle is nucleated at a certain location in the melt and grows according to a specific atomic arrangement. By controlling the volume percentage of the matrix phase, ensuring that each intermolecular particle can be dispersed, it is difficult for the individual intermolecular dispersed particles to bond and entangle. Therefore, the final dispersed Fe-rich dispersed particle phases are mostly single-crystal phases. Even the protruding short dendrites that grow further on the spherical particles grow according to the fixed crystal orientation of the sphere surface, that is, the sphere and the protruding short dendrites are a single grain. For polycrystalline materials, their grain boundaries generally tend to contain impurity elements discharged from the grain during solidification, making it difficult to obtain high-purity polycrystalline powder materials. However, when the powder material is mainly composed of single-crystal particles, its purity can be guaranteed. Moreover, the atoms on the surface of single crystal particles have specific arrangements, such as (111) plane arrangement, which endow the material with special mechanical, physical and chemical properties, thereby producing beneficial effects.

[0248] Therefore, this invention, through careful design, incorporates T-type, M-type, and D-type elements into an alloy melt mainly composed of La and Fe, achieving solid solution alloying of these elements, along with La, within spherical or near-spherical Fe-rich dispersed particle phases. This improves the corrosion and oxidation resistance of the spherical or near-spherical Fe-rich dispersed particle phase and reduces impurity content. By removing the La-rich matrix phase, ultrafine spherical iron alloy powder materials with particle sizes ranging from hundreds of nanometers to several micrometers are obtained, showing promising applications in powder metallurgy, metal injection molding (MIM), 3D printing, magnetic materials, heat-resistant materials, high-temperature alloys, coatings, electrothermal materials, and microwave absorbing materials.

[0249] Note: In one to fourteen aspects of this application, T includes at least one of Cr and V, M includes at least one of Al, Ni, Co, and Si, and D includes at least one of Mo, W, and Ti. Attached Figure Description

[0250] Figure 1 The backscattered SEM morphology of the initial alloy solidification structure described in Example 1;

[0251] Figure 2 The SEM morphology of the iron alloy powder material prepared in Example 1 is shown below.

[0252] Figure 3 The backscattered SEM morphology of the initial alloy solidification structure described in Example 2;

[0253] Figure 4The image shows the backscattered high-magnification SEM morphology of the initial alloy solidification matrix described in Example 2.

[0254] Figure 5 The backscattered SEM morphology of the initial alloy solidification structure described in Example 3;

[0255] Figure 6 The image shows the backscattered high-magnification SEM morphology of the initial alloy solidification matrix described in Example 3.

[0256] Figure 7 The backscattered SEM morphology of the initial alloy solidification structure described in Example 4;

[0257] Figure 8 The backscattered SEM morphology of the initial alloy solidification structure described in Example 5;

[0258] Figure 9 The backscattered SEM morphology of the initial alloy solidification structure described in Example 6;

[0259] Figure 10 The backscattered SEM morphology of the initial alloy solidification structure described in Example 7;

[0260] Figure 11 The backscattered SEM morphology of the initial alloy solidification structure described in Example 8;

[0261] Figure 12 The SEM morphology of the iron alloy powder material described in Example 8;

[0262] Figure 13 The backscattered SEM morphology of the initial alloy solidification structure described in Example 10;

[0263] Figure 14 The backscattered SEM morphology of the initial alloy solidification structure described in Example 11;

[0264] Figure 15 The SEM morphology of the iron alloy powder material described in Example 11;

[0265] Figure 16 The backscattered SEM morphology of the initial alloy solidification structure described in Example 12;

[0266] Figure 17 The backscattered SEM morphology of the initial alloy solidification structure described in Example 13;

[0267] Figure 18 The SEM morphology of the iron alloy powder material described in Example 13;

[0268] Figure 19 The backscattered SEM morphology of the initial alloy solidification structure described in Example 14;

[0269] Figure 20 The backscattered SEM morphology of the initial alloy solidification structure described in Example 15;

[0270] Figure 21 The backscattered SEM morphology of the initial alloy solidification structure described in Example 16;

[0271] Figure 22 The SEM morphology of the iron alloy powder material described in Example 16;

[0272] Figure 23 For comparison, the backscattered SEM morphology of the initial alloy solidification structure described in Example 1;

[0273] Figure 24 For comparison, the SEM morphology of the iron-rich dendrites described in Example 1;

[0274] Figure 25 For comparison, the backscattered SEM morphology of the initial alloy solidification structure described in Example 2;

[0275] Figure 26 For comparison, the backscattered SEM morphology of the initial alloy solidification structure described in Example 3;

[0276] Figure 27 For comparison, the backscattered SEM morphology of the initial alloy solidification structure described in Example 4;

[0277] Figure 28 For comparison, the high-magnification backscattered SEM morphology of the initial alloy solidification structure described in Example 4; Detailed Implementation

[0278] The present invention will be further described in detail below with reference to the embodiments. It should be noted that the embodiments described below are intended to facilitate the understanding of the present invention and do not limit it in any way.

[0279] Example 1

[0280] Using commercially available La, Fe, and Cr raw materials, according to the nominal atomic percentage composition La 50 Fe 41 The main component of Cr9 smelting is La. 50 Fe 41 The initial alloy melt of Cr9 was solidified at a cooling rate of approximately 100 K / s into an initial alloy plate with a thickness of approximately 5 mm. The solidification microstructure of the initial alloy plate is as follows: Figure 1 As shown, it includes Fe as its main component. 79 Cr 20The dispersed particulate phase of La1 and the matrix phase whose main component is La, wherein the volume percentage of the matrix phase exceeds 65%; Cr and La are both dissolved in the dispersed particulate phase; the dispersed particulate phase includes spherical particulate phase and dendritic particulate phase, and the volume percentage of the spherical particulate phase exceeds 50%; the particle size range of the spherical particulate phase is 15nm-60μm.

[0281] The La matrix phase in the initial alloy plate was removed by reactive etching using a 0.5 mol / L dilute hydrochloric acid solution, yielding a dispersed alloy primarily composed of Fe. 79 Cr 20 The La1 ferroalloy powder material comprises spherical particles and dendritic particles, with the volume percentage of spherical particles exceeding 50%; the particle size of the spherical particles ranges from 15 nm to 60 μm. Figure 2 As shown. Some spherical or near-spherical grains contain certain dendritic features, such as... Figure 2 The illustration shows the dendritic protrusions on the spherical particles. The prepared ferroalloy powder material can be used in general powder metallurgy and metal injection molding (MIM) fields.

[0282] Example 2

[0283] Using commercially available La, Fe, and Cr raw materials, according to the nominal atomic percentage composition La 50 Fe 41 The main component of Cr9 smelting is La. 50 Fe 41 The initial alloy melt of Cr9 was cooled at a rate of approximately 5000 K / s and solidified into initial alloy strips with a thickness of approximately 200 μm using a strip-throwing method. The solidification microstructure of the initial alloy strips is as follows: Figure 3 As shown, the main component detected is Fe. 77 Cr 22 The dispersed granular phase of La1 and the matrix phase, whose main component is La, together constitute a matrix phase, with the matrix phase accounting for over 65% of the volume. The dispersed granular phase is almost entirely composed of spherical particles; some of the spherical particles exhibit certain dendritic characteristics, such as... Figure 3 The illustration shows a dendritic protrusion structure on a spherical granular phase. The particle size of the spherical granular phase ranges from 15 nm to 10 μm. Figure 3 Magnified matrix phase, some nano-spherical particles can also be found, such as... Figure 4 As shown.

[0284] The La matrix phase in the initial alloy strip was removed by reactive etching using a 0.5 mol / L dilute sulfuric acid solution, yielding a dispersed strip with Fe as the main component. 77 Cr 22The La1 ferroalloy powder material consists almost entirely of spherical particles, with some spherical particles exhibiting dendritic characteristics; the particle size ranges from 15 nm to 10 μm. The prepared powder material can be used in general powder metallurgy and metal injection molding (MIM) fields.

[0285] Example 3

[0286] Using commercially available La, Fe, and V raw materials, the nominal component La was determined by atomic percentage. 67 Fe 30 The main component of V3 smelting is La. 67 Fe 30 The initial alloy melt of V3 was solidified at a cooling rate of approximately 1000 K / s into initial alloy strips with a thickness of approximately 500 μm. The solidification microstructure of the initial alloy strips is as follows: Figure 5 As shown, the main component detected is Fe. 88.5 V9La 1.5 The dispersed particulate phase and the matrix phase whose main component is La, wherein the volume percentage of the matrix phase exceeds 70%; the dispersed particulate phase is mainly spherical; the particle size range of the spherical particulate phase is 15 nm-5 μm. Figure 5 Magnified matrix phase, some nano-spherical particles can also be found, such as... Figure 6 As shown (the actual matrix phase is outside the nanospheres), and a small amount of the particle phase is dendritic particles.

[0287] The La matrix phase in the initial alloy strip was removed by reactive etching with 0.5 mol / L dilute hydrochloric acid, thus obtaining a dispersed strip with Fe as the main component. 88.5 V9La 1.5 The iron alloy powder material is mainly composed of spherical particles, with only a small amount of dendritic particles. The particle size of the spherical particles ranges from 15 nm to 5 μm.

[0288] Example 4

[0289] Using commercially available low-purity La, low-purity Fe, low-purity V, and low-purity Cr raw materials containing high O impurities, the nominal composition of La was determined according to atomic percentage. 67 Fe 30 The main component of Cr3V3 smelting is approximately La. 65 Fe 30 The initial alloy melt of Cr3V3O2 solidified at a cooling rate of approximately 250 K / s into an initial alloy band with a thickness of approximately 3 mm. The solidification microstructure of the initial alloy band is as follows: Figure 7 As shown, the main component detected is Fe. 82.3 V8Cr8La 1.5 O 0.2The dispersed particulate phase and the matrix phase, which is mainly composed of La and enriched with oxygen impurities, wherein the volume percentage of the matrix phase exceeds 70%; the dispersed particulate phase is mainly spherical, including a small amount of dendrites; the particle size of the spherical particulate phase ranges from 15nm to 15μm, and some of the spherical particulate phases contain certain dendritic features.

[0290] The La-rich matrix phase in the initial alloy thick strip was removed by reactive corrosion using 0.2 mol / L dilute nitric acid, resulting in a dispersed alloy with Fe as the main component. 82.3 V8Cr8La 1.5 O 0.2 The iron alloy powder material is mainly spherical in shape, including a small number of dendritic particles, and some spherical particles contain certain dendritic characteristics. The particle size range of the spherical particles is 15nm-15μm.

[0291] Example 5

[0292] Using commercially available La, Fe, Cr, and Mo raw materials, the nominal composition of La was determined according to atomic percentage. 50 Fe 40 Cr 0.5 Mo 9.5 The main component of the smelting is La. 50 Fe 40 Cr 0.5 Mo 9.5 The initial alloy melt was cooled at a rate of approximately 250 K / s and solidified into an initial alloy band approximately 3 mm thick. The solidification microstructure of the initial alloy band is as follows: Figure 8 As shown, the main component detected is Fe. 78 Mo 20 The Cr1La1 dispersed particle phase and the matrix phase whose main component is La, wherein the volume percentage of the matrix phase exceeds 70%; the dispersed particle phase is mainly spherical; the particle size of the spherical dispersed particle phase ranges from 15nm to 15μm, and some of the spherical particle phases contain certain dendritic features.

[0293] The La matrix phase in the initial alloy thick strip was removed by reactive etching with 0.5 mol / L dilute hydrochloric acid, thus obtaining a dispersed alloy mainly composed of Fe. 78 Mo 20 The Cr1La1 ferroalloy powder material is mainly composed of spherical particles, and some of the spherical particles contain certain dendritic features; the particle size range of the spherical particles is 15nm-15μm.

[0294] Example 6

[0295] Using commercially available La, Fe, Cr, and Si raw materials, the nominal composition of La was determined according to atomic percentage. 34 Fe40 Cr 2.5 Si 23.5 Smelting mainly produces La 34 Fe 40 Cr 2.5 Si 23.5 The initial alloy melt was cooled at a rate of approximately 100 K / s and solidified into an initial alloy band approximately 5 mm thick. The solidification microstructure of the initial alloy band is as follows: Figure 9 As shown, the main component detected is Fe. 85.2 Cr8Si6La 0.8 The black dispersed granular phase and the main component is La 64 Si 36 The white matrix phase and the main component is La 34 Si 33 Fe 33 The matrix phase is gray, with the volume percentage of two matrix phases exceeding 70%; the dispersed particulate phase is mainly nearly spherical. The particle size range of the nearly spherical particulate phase is 50 nm-5 μm.

[0296] The La in the initial alloy thick strip was removed by using a mixed solution of 0.5 mol / L dilute hydrochloric acid and 1 mol / L hydrofluoric acid. 64 Si 36 matrix phase and La 34 Si 33 Fe 33 The matrix phase is removed by reactive corrosion, resulting in a dispersed composition primarily of Fe. 85.2 Cr8Si6La 0.8 The iron alloy powder material has a predominantly near-spherical shape, with particle sizes ranging from 50 nm to 5 μm. The prepared powder material can be used in the field of magnetic materials, such as magnetic powder cores.

[0297] Example 7

[0298] Using commercially available La, Fe, Cr, and Si raw materials, the nominal composition of La was determined according to atomic percentage. 34 Fe 40 Cr 2.5 Si 23.5 Smelting mainly produces La 34 Fe 40 Cr 2.5 Si 23.5 The initial alloy melt, approximately 10 homogeneous initial alloy melts. 5 The initial alloy strip solidified at a cooling rate of K / s, forming an initial alloy strip with a thickness of approximately 100 μm. The solidification microstructure of the initial alloy strip is as follows: Figure 10 As shown, the main component detected is Fe. 82.5 Cr8Si8La1.5 The black dispersed granular phase and the average composition are mainly La 60 Si 20 Fe 20 The matrix phase comprises more than 70% by volume; the dispersed particulate phase is mainly composed of fine spheres. The particle size range of the spherical particulate phase is 15 nm to 2 μm.

[0299] The initial alloy strip, whose average composition was mainly La, was treated with a mixed solution of 0.5 mol / L dilute hydrochloric acid and 1 mol / L hydrofluoric acid. 60 Si 20 Fe 20 The matrix phase is removed by reaction corrosion, resulting in a dispersed product whose main component is Fe. 82.5 Cr8Si8La 1.5 The prepared Si-containing iron alloy powder material has a predominantly near-spherical shape, with particle sizes ranging from 15 nm to 2 μm. This powder material can be used in the field of magnetic materials, such as magnetic powder cores.

[0300] Example 8

[0301] Using commercially available La, Fe, Cr, and Si raw materials, the nominal composition of La was determined according to atomic percentage. 50 Fe 40 The main component of Cr5Si5 smelting is La. 50 Fe 40 The initial alloy melt of Cr5Si5 was solidified at a cooling rate of approximately 250 K / s into an initial alloy band with a thickness of approximately 3 mm. The solidification microstructure of the initial alloy band is as follows: Figure 11 As shown, the main component detected is Fe. 86 Cr 12 The dispersed particulate phase of Si1La1 and the main component of La 92 The matrix phase of Si8 comprises more than 70% by volume; the dispersed particulate phase is mainly spherical, but also includes a small amount of dendritic particles; and some of the spherical particles contain certain dendritic characteristics. The particle size range of the spherical particles is 15 nm to 40 μm.

[0302] The LaSi matrix phase in the initial alloy strip was removed by reactive etching using a mixed solution of 0.5 mol / L dilute hydrochloric acid, 0.1 mol / L dilute nitric acid, and 0.5 mol / L hydrofluoric acid (hydrofluoric acid can remove Si), thus obtaining a dispersed strip with Fe as the main component. 86 Cr 12 The Si1La1 ferroalloy powder material is mainly composed of spherical particles, with a small amount of dendritic particles, and some of the spherical particles contain certain dendritic characteristics. The particle size range of the spherical particles is 15nm-40μm. Figure 12 As shown.

[0303] Example 9

[0304] Using commercially available La, Fe, Cr, and Si raw materials, the nominal composition of La was determined according to atomic percentage. 50 Fe 41 The main component of Cr4Si5 smelting is La. 50 Fe 41 The initial alloy melt of Cr4Si5 was solidified at a cooling rate of approximately 1000 K / s into an initial alloy ribbon with a thickness of approximately 500 μm. The solidification microstructure of the initial alloy ribbon, as determined by testing, is predominantly Fe. 90.5 Cr8Si 0.5 The dispersed particulate phase of La1 and its main component is La 94 The matrix phase of Si6 comprises more than 70% by volume; the dispersed particle phase is mainly spherical, but also includes a small amount of dendritic particles; and some of the spherical particles contain certain dendritic characteristics. The particle size range of the spherical particles is 15 nm to 10 μm.

[0305] The La in the initial alloy band LaSi matrix phase was removed by a dealloying reaction using 0.5 mol / L dilute hydrochloric acid, while retaining most of the Si (Si generally does not react with dilute hydrochloric acid), resulting in a dispersion with Fe as the main component. 90.5 Cr8Si 0.5 The composite powder is composed of La1 ferroalloy powder and nanoporous Si; wherein the nanoporous Si has a fragmented porous structure, the ferroalloy powder is mainly composed of spherical particles, and also includes a small amount of dendritic particles, and some of the spherical particles contain certain dendritic characteristics, and the particle size range of the spherical particles is 15nm-10μm.

[0306] After compacting the spherical iron alloy powder and the composite powder of nanoporous Si, vacuum solid silicon infiltration was performed at 1000℃ for 4 hours. Then, the powder was dispersed to obtain a powder with a composition of approximately Fe. 82 Cr7Si 10 La1 high-silicon-content iron-chromium-silicon powder.

[0307] The prepared high-silicon-content iron-chromium-silicon powder, after sieving, selects powder with a particle size of 3μm-10μm, which can be used in the field of soft magnetic materials, such as magnetic powder cores.

[0308] Example 10

[0309] Using commercially available La, Fe, Cr, and Al raw materials, the nominal composition of La was determined according to atomic percentage. 45 Fe 27.5 Cr 7.5 Al 20 The main component of the smelting is La.45 Fe 27.5 Cr 7.5 Al 20 The initial alloy melt was cooled at a rate of approximately 250 K / s and solidified into an initial alloy band approximately 3 mm thick. The solidification microstructure of the initial alloy band is as follows: Figure 13 As shown, the main component detected is Fe. 72 Cr 20 The dispersed particulate phase of Al7La1 and the main component is La 75 Al 25 The matrix phase comprises more than 70% by volume; the dispersed particulate phase is mainly spherical, but also includes a small amount of dendritic particles; and some of the spherical particulate phases contain certain dendritic characteristics. The particle size range of the spherical particulate phase is 15 nm to 10 μm.

[0310] The La in the initial alloy thick strip was removed by using 0.5 mol / L dilute hydrochloric acid. 75 Al 25 The matrix phase is removed by reactive corrosion, resulting in a dispersed composition primarily of Fe. 72 Cr 20 The Al7La1 ferroalloy powder material is mainly composed of spherical particles, with a small number of dendritic particles, and some of the spherical particles contain certain dendritic characteristics. The particle size range of the spherical particles is 15 nm to 10 μm. The prepared powder material can be used in the fields of electrothermal alloys, heat-resistant alloys, and heat-resistant coatings.

[0311] Example 11

[0312] Using commercially available La, Fe, Cr, and Al raw materials, the nominal composition of La was determined according to atomic percentage. 45 Fe 27.5 Cr 7.5 Al 20 The main component of the smelting is La. 45 Fe 27.5 Cr 7.5 Al 20 The initial alloy melt, approximately 10 homogeneous initial alloy melts. 4 The initial alloy ribbon solidified at a cooling rate of K / s, resulting in an initial alloy ribbon with a thickness of approximately 150 μm. The solidification microstructure of the initial alloy ribbon is as follows: Figure 14 As shown, the main component detected is Fe. 71 Cr 21 The dispersed particulate phase of Al7La1 and the main component is La 75 Al 25The matrix phase comprises more than 70% by volume; the dispersed particulate phase is almost entirely spherical, and some of the spherical particulate phases contain certain dendritic features. The particle size range of the spherical particulate phase is 5 nm to 5 μm.

[0313] The La in the initial alloy thick strip was removed by using 0.5 mol / L dilute hydrochloric acid. 75 Al 25 The matrix phase is removed by reactive corrosion, resulting in a dispersed composition primarily of Fe. 71 Cr 21 Ferroalloy powder materials of Al7La1, such as Figure 15 As shown, their shapes are almost entirely spherical, and some spherical particles contain certain dendritic features, such as... Figure 15 As shown in the illustration, the spherical particles have a particle size range of 5 nm to 5 μm. The prepared powder material can be used in the fields of electrothermal alloys, heat-resistant alloys, and heat-resistant coatings.

[0314] Example 12

[0315] Using commercially available raw materials of La, Fe, Cr, Al, and Mo, the nominal composition of La was determined according to atomic percentage. 38 Fe 25 Cr 10 Al 25 The main component of Mo2 smelting is La. 38 Fe 25 Cr 10 Al 25 The initial alloy melt of Mo2 was solidified at a cooling rate of approximately 500 K / s into an initial alloy band with a thickness of approximately 1 mm. The solidification microstructure of the initial alloy band is as follows: Figure 16 As shown, the main component detected is Fe. 60 Cr 25 The dispersed particulate phase and main component of Al8Mo6La1 are La, respectively. 50 Al 50 (gray laths and fibrous phases) and La 75 Al 25 The matrix phase is a white phase, wherein the total volume percentage of the matrix phase exceeds 70%; the dispersed particle phase is mainly spherical, but also includes a small amount of dendritic particles; and some of the spherical particles contain certain dendritic characteristics. The particle size range of the spherical particles is 15nm-40μm.

[0316] The La in the initial alloy thick strip was removed by using 1 mol / L dilute hydrochloric acid. 50 Al 50 with La 75 Al 25 The matrix phase is removed by reactive corrosion, resulting in a dispersed composition primarily of Fe. 60Cr 25 The Al8Mo6La1 ferroalloy powder material is mainly composed of spherical particles, with a small amount of dendritic particles, and some of the spherical particles exhibit certain dendritic characteristics. The particle size range of the spherical particles is 15 nm-40 μm. The prepared powder material can be used in the fields of electrothermal alloys, heat-resistant alloys, and heat-resistant coatings. Due to the presence of Mo, the powder material exhibits higher temperature resistance and corrosion resistance.

[0317] Example 13

[0318] Using commercially available La, Fe, Cr, and Co raw materials, the nominal composition of La was determined according to atomic percentage. 27.5 Fe 37.5 Cr 10 Co 25 The main component of the smelting is La. 27.5 Fe 37.5 Cr 10 Co 25 The initial alloy melt was cooled at a rate of approximately 250 K / s and solidified into an initial alloy band approximately 3 mm thick. The solidification microstructure of the initial alloy band is as follows: Figure 17 As shown, the main component detected is Fe. 63 Cr 19 Co 17 The dispersed particulate phase of La1 and its main component is La 60 Co 40 The matrix phase comprises more than 50% by volume; the dispersed particulate phase is almost entirely spherical, including only a small amount of dendrites; and some of the spherical particulate phases contain certain dendritic characteristics. The particle size range of the spherical particulate phase is 15 nm to 6 μm.

[0319] The La in the initial alloy thick strip was removed by using 1 mol / L dilute hydrochloric acid. 60 Co 40 The matrix phase is removed by reactive corrosion, resulting in a dispersed composition primarily of Fe. 63 Cr 19 Co 17 La1 iron alloy powder materials, such as Figure 18 As shown, the particles are mainly spherical, with a small number of dendritic particles, and some of the spherical particles contain certain dendritic features. The particle size range of the spherical particles is 15 nm to 6 μm. The prepared powder material can be used in the field of magnetic materials.

[0320] Example 14

[0321] Using commercially available La, Fe, Cr, and Ni raw materials, the nominal composition of La was determined according to atomic percentage. 27.5 Fe 37.5 Cr10 Ni 25 The main component of the smelting is La. 27.5 Fe 37.5 Cr 10 Ni 25 The initial alloy melt was cooled at a rate of approximately 250 K / s and solidified into an initial alloy band approximately 3 mm thick. The solidification microstructure of the initial alloy band is as follows: Figure 19 As shown, the main component detected is Fe. 70 Cr 20 The dispersed particulate phase of Ni9La1 and its main components are approximately La. 50 Ni 50 with La 75 Ni 25 The matrix phase comprises more than 50% by volume; the dispersed particulate phase is mainly spherical, including a small amount of dendrites; and some of the spherical particulate phases contain certain dendritic features. The particle size range of the spherical particulate phase is 15 nm to 50 μm.

[0322] The La in the initial alloy strip was removed by using 1 mol / L dilute hydrochloric acid. 50 Ni 50 with La 75 Ni 25 The matrix phase is removed by reaction corrosion, resulting in a dispersed product whose main component is Fe. 70 Cr 20 The Ni9La1 iron alloy powder material is mainly composed of spherical particles, with a small number of dendritic particles. Some of the spherical particles have certain dendritic characteristics, and the particle size range of the spherical particles is 15nm-50μm.

[0323] Example 15

[0324] Using commercially available La, Fe, Cr, Ni, Mo, and Ti raw materials, the nominal composition of La was determined according to atomic percentage. 35 Fe 36 Cr 10 Ni 15 The main component of Mo1Ti2 smelting is La. 35 Fe 36 Cr 10 Ni 15 The initial alloy melt of Mo1Ti2 was solidified at a cooling rate of approximately 50 K / s into button ingots with a thickness of 6 mm and a diameter of 12 mm. The solidification microstructure of the initial alloy button ingots is as follows: Figure 20 As shown, the main component detected is Fe. 70 Cr 20 The dispersed particulate phase of Ni3Mo2Ti4La1 has an average composition mainly of La. 81Ni 19 The matrix phase (composed of La phase and La3Ni phase) has a total volume percentage of over 70%; the dispersed particle phase is almost entirely spherical, including only a small amount of dendrites; and some of the spherical particle phases contain certain dendritic characteristics. The particle size range of the spherical particle phase is 15nm-50μm.

[0325] The La in the initial alloy button ingot was removed by using a 1 mol / L hydrochloric acid solution. 81 Ni 19 The matrix phase is removed by reactive corrosion, while the corrosion-resistant dispersed particulate phase is retained, resulting in a dispersed phase whose main component is Fe. 70 Cr 20 The material is a spherical iron alloy powder material of Ni3Mo2Ti4La1; wherein the iron alloy powder is mainly spherical particles, and also includes a small amount of dendritic particles, and some spherical particles contain certain dendritic characteristics, and the particle size range of the spherical particles is 15nm-50μm.

[0326] Example 16

[0327] Using commercially available La, Fe, Cr, and Ni raw materials, the nominal composition of La was determined according to atomic percentage. 27.5 Fe 37.5 Cr 10 Ni 25 The main component of the smelting is La. 27.5 Fe 37.5 Cr 10 Ni 25 The initial alloy melt was cooled at a rate of approximately 5000 K / s and solidified into an initial alloy ribbon with a thickness of approximately 200 μm. The solidification microstructure of the initial alloy ribbon is as follows: Figure 21 As shown, the main component detected is Fe. 70 Cr 20 The dispersed particulate phase and average composition of Ni9La1 are mainly La. 60 Ni 40 The matrix phase comprises more than 50% by volume; the dispersed particulate phase is almost entirely spherical, including only a small amount of dendrites; and some of the spherical particulate phases contain certain dendritic characteristics. The particle size range of the spherical particulate phase is 15 nm to 6 μm.

[0328] La in the matrix phase of the initial alloy strip was removed by a dealloying reaction using 0.2 mol / L dilute hydrochloric acid, while retaining some nanoporous Ni, thus obtaining a dispersed strip with Fe as the main component. 70 Cr 20 Spherical iron alloy powder material of Ni9La1 and composite powder of nanoporous Ni, such as Figure 22As shown, the flocculent material on the outside of the spherical particles is nanoporous Ni; the iron alloy powder is mainly composed of spherical particles, and also includes a small number of dendritic particles, and some of the spherical particles contain certain dendritic characteristics. The particle size range of the spherical particles is 15nm-6μm.

[0329] The main component is Fe 70 Cr 20 Spherical iron alloy powder of Ni9La1 and composite powder of nanoporous Ni were pressed into a billet under 100 MPa, and then heat-treated at 1300℃ for 4 h in a protective atmosphere to obtain a product with a composition of approximately Fe. 52 Cr 15 Ni 33 La1 high-nickel content iron-chromium-nickel superalloy products.

[0330] Example 17

[0331] Using commercially available La, Fe, and Cr raw materials, according to the nominal atomic percentage composition La 45 Fe 40 Cr 15 The main component of the smelting is La. 45 Fe 40 Cr 15 The initial alloy melt, approximately 10 homogeneous initial alloy melts. 6 K / s-10 7 The initial alloy strip solidifies at a cooling rate of K / s to form an initial alloy strip with a thickness of approximately 20 μm. The solidification microstructure of the initial alloy strip consists of a Fe-rich dispersed nanoparticle phase (the particles are too small for direct compositional analysis) and a matrix phase whose main component is La, with the matrix phase comprising more than 60% by volume. The dispersed particle phase consists almost entirely of near-spherical nanoparticles. Some of the spherical particles exhibit dendritic characteristics, and the particle size range of the spherical particles is 5 nm to 200 nm.

[0332] The La matrix phase in the initial alloy strip was removed by reactive etching using a 0.5 mol / L dilute hydrochloric acid solution, resulting in a dispersed sample primarily composed of Fe. 71 Cr 27 La2 nano-iron alloy powder material (because of the presence of Cr, Fe 71 Cr 27 La2 nano-iron alloy powder particles are not easily dissolved by acid reaction. They are almost all spherical particles, and some spherical particles contain certain dendritic characteristics. The particle size range of the nano-iron alloy powder material is 5nm-200nm.

[0333] Example 18

[0334] Using commercially available La, Fe, and Cr raw materials, according to the nominal atomic percentage composition La50 Fe 46 The main component of Cr4 smelting is La. 50 Fe 46 The initial alloy melt of Cr4 will form a homogeneous initial alloy melt of approximately 10. 4 The initial alloy ribbon solidified at a cooling rate of K / s, forming a thickness of approximately 150 μm. The solidification microstructure of the initial alloy ribbon consisted mainly of Fe. 91 The dispersed granular phase of Cr8La1 is composed of a matrix phase whose main component is La. Both Cr and La are dissolved in the dispersed granular phase. The iron-rich dispersed granular phase is mainly composed of spherical particles, and also includes a small amount of dendritic particles. Some of the spherical particles contain certain dendritic characteristics. The particle size range of the iron-rich spherical particles is 15nm-10μm.

[0335] The La matrix phase in the initial alloy strip was removed by reactive etching using a 0.5 mol / L dilute hydrochloric acid solution, resulting in a dispersed alloy primarily composed of Fe. 91 The Cr8La1 ferroalloy powder material includes spherical particles and dendritic particles, and is mainly composed of spherical particles, with some spherical particles containing certain dendritic characteristics; the particle size range of the spherical particles is 15nm-10μm.

[0336] The obtained ferroalloy powder material is subjected to gas silicon infiltration treatment in a mixed gas of silicon chloride (SiCl4, or Si2Cl6, or a mixture of SiCl4 and Si2Cl6) and hydrogen at a temperature of 400℃-1000℃ to obtain spherical ferroalloy powder material with high silicon content and a composition of approximately Fe. 81.5 Cr7Si 10.5 La1, whose shape remains largely unchanged from before silicon infiltration, includes spherical particles and dendritic particles, mainly composed of spherical particles, and some spherical particles contain certain dendritic features; the particle size range of the spherical particles is 15nm-10μm.

[0337] After sieving, Fe particles in the 1μm-10μm range were selected. 81.5 Cr7Si 10.5 La1 powder is coated with insulating material, and then a magnetic powder core is prepared.

[0338] Example 19

[0339] Using commercially available La, Fe, and Cr raw materials, according to the nominal atomic percentage composition La 35 Fe 50 Cr 15 The main component of the smelting is La. 35 Fe 50 Cr 15 The initial alloy melt, a homogeneous initial alloy melt, is prepared at approximately 10...3 K / s-10 6 A cooling rate of K / s was used to solidify the initial alloy powder into particles ranging from 5 μm to 300 μm using atomization powdering technology. The solidified microstructure of the initial alloy powder, as determined by testing, showed that the main component was Fe. 75.5 Cr 23 La 1.5 The mixture consists of a dispersed particulate phase and a matrix phase whose main component is La, wherein the volume percentage of the matrix phase exceeds 50%; the dispersed particulate phase is almost entirely composed of spherical particles; some of the spherical particles contain certain dendritic features. The particle size range of the spherical particles is 5 nm to 10 μm.

[0340] The La matrix phase in the initial alloy powder was removed by reactive corrosion using a 0.5 mol / L dilute hydrochloric acid solution, resulting in a dispersed powder primarily composed of Fe. 75.5 Cr 23 La 1.5 A finer ferroalloy powder material is prepared, which consists almost entirely of spherical particles, with some spherical particles containing certain dendritic characteristics; the particle size range of the spherical particles is 5 nm-10 μm. The prepared powder material can be used in general powder metallurgy and metal injection molding (MIM) fields.

[0341] Example 20

[0342] Using commercially available La, Fe, Mo, and Cr raw materials, the nominal composition of La was determined according to atomic percentage. 50 Fe 49 Cr 0.5 Mo 0.5 The main component of the smelting is La. 50 Fe 49 Cr 0.5 Mo 0.5 The initial alloy melt, approximately 10 homogeneous initial alloy melts. 7 K / s-10 8 The initial alloy strips solidify at a cooling rate of K / s, forming initial alloy strips with a thickness of approximately 15 μm to 20 μm. The solidification microstructure of the initial alloy strips comprises a Fe-rich dispersed nanoparticle phase and a matrix phase whose main component is La, wherein the volume percentage of the matrix phase exceeds 65%; the dispersed particle phase consists almost entirely of near-spherical nanoparticles; some of the spherical particle phases contain certain dendritic features, and the particle size range of the spherical particle phase is 5 nm to 100 nm.

[0343] The La matrix phase in the initial alloy strip was removed by reactive etching using a 0.25 mol / L dilute hydrochloric acid solution, resulting in a dispersed sample primarily composed of Fe. 97 Cr1Mo1La1 nano-iron alloy powder material (due to the presence of Cr and Mo, nano-Fe...) 97The Cr1Mo1La1 ferroalloy powder particles are not easily dissolved by 0.25 mol / L dilute hydrochloric acid. Almost all of them are spherical particles, and some of the spherical particles contain certain dendritic characteristics. The nano-Fe... 97 The particle size range of Cr1Mo1La1 ferroalloy powder is 5nm-100nm.

[0344] The obtained nano Fe 97 Cr1Mo1La1 ferroalloy powder particles were used as magnetic solid particles. Sodium dodecyl sulfate (SDS) and oleic acid were used as surfactants, and ethanol was used as a carrier liquid to prepare a magnetic fluid.

[0345] Example 21

[0346] Using commercially available La, Fe, and Cr raw materials, according to the nominal atomic percentage composition La 50 Fe 47 The main component of Cr3 smelting is La. 50 Fe 47 The initial alloy melt of Cr3, approximately 10 homogeneous initial alloy melts. 6 K / s-10 8 The initial alloy strips solidify at a cooling rate of K / s, forming initial alloy strips with a thickness of approximately 15 μm to 20 μm. The solidification microstructure of the initial alloy strips comprises a Fe-rich dispersed nanoparticle phase and a matrix phase whose main component is La, wherein the volume percentage of the matrix phase exceeds 65%; the dispersed particle phase consists almost entirely of near-spherical nanoparticles; some of the spherical particle phases contain certain dendritic features, and the particle size range of the spherical particle phase is 5 nm to 50 nm.

[0347] The La matrix phase in the initial alloy strip was removed by reactive etching using a 0.5 mol / L dilute hydrochloric acid solution, resulting in a dispersed sample primarily composed of Fe. 93 Cr6La1 nano-iron alloy powder material (because of the presence of Cr, nano-Fe...) 93 Cr6La1 ferroalloy powder particles are not easily dissolved by 0.5 mol / L dilute hydrochloric acid. They are almost entirely spherical particles, and some of these spherical particles contain certain dendritic characteristics. The nano-Fe... 93 The particle size range of Cr6La1 ferroalloy powder is 5nm-50nm.

[0348] The obtained nano Fe 93 Cr6La1 iron alloy powder particles were used as magnetic solid particles to prepare magnetic fluids using mercury as the carrier liquid.

[0349] Comparative Example 1

[0350] Using commercially available La and Fe raw materials, according to the nominal composition La by atomic percentage50 Fe 50 The main component of the smelting is La. 50 Fe 50 The initial alloy melt was cooled at a rate of approximately 250 K / s and solidified into an initial alloy band approximately 3 mm thick. The solidification microstructure of the initial alloy band is as follows: Figure 23 As shown, it includes Fe as its main component. 99 The dispersed dendritic phase of La1 is composed of a matrix phase whose main component is La, with the matrix phase accounting for over 70% of the volume. The dispersed dendritic phase is almost entirely dendritic. Figure 23 The seemingly spherical parts arranged in a regular pattern are actually the cross-sectional morphology of dendrite branches, and each row of cross-sectional branches actually belongs to a large dendrite.

[0351] The La matrix phase in the initial alloy thick strip was removed by reactive etching using a 0.5 mol / L dilute hydrochloric acid solution, thus obtaining a dispersed alloy mainly composed of Fe. 99 La1 iron alloy dendritic powder material, its shape is mainly dendrite, and spherical particles are not seen, such as Figure 24 As shown, it also clearly shows that a large dendrite has rows of secondary dendrites, and the cross-sections of these secondary dendrites correspond to... Figure 23 The diagram shows a regular arrangement of "sphere" (actually strip-shaped) cross-sectional morphologies. Therefore, La 50 Fe 50 The alloy can only obtain large, well-grown iron-rich dendrites by slow cooling rates, but not iron-rich spherical particles.

[0352] Comparative Example 2

[0353] Using commercially available La and Fe raw materials, according to the nominal composition La by atomic percentage 50 Fe 50 The main component of the smelting is La. 50 Fe 50 The initial alloy melt, approximately 10 homogeneous initial alloy melts. 5 The initial alloy strip solidified at a cooling rate of K / s, forming an initial alloy strip with a thickness of approximately 100 μm. The solidification microstructure of the initial alloy strip is as follows: Figure 25 As shown, it includes Fe as its main component. 99 The dispersed dendritic phase of La1 is in contrast to the matrix phase, which is mainly composed of La; the dispersed dendritic phase is almost entirely dendritic. Figure 25 The seemingly short, rod-shaped, iron-rich black phases adjacent to each other actually belong to one or more dendrites, and these dendrites are approximately 1-2 μm in size. Because the secondary structure of the dendrites is nanoscale, and Fe... 99La1 is not resistant to acid corrosion. When acid corrosion is used, the nano-sized iron-rich dendrites will also be corroded by the reaction, making it difficult to obtain the original iron-rich particles. Therefore, even with a very high cooling rate, if the initial alloy melt does not contain T or D type elements, it is difficult to obtain spherical iron-rich particle phases, and the corrosion resistance of the iron-rich particles cannot be improved, making them easy to separate by acid reaction.

[0354] Comparative Example 3

[0355] Using commercially available La, Fe, and Hf raw materials, the nominal composition of La was determined by atomic percentage. 50 Fe 40 Hf 10 The main component of the smelting is La. 50 Fe 40 Hf 10 The initial alloy melt was cooled at a rate of approximately 500 K / s and solidified into an initial alloy band approximately 1 mm thick. The solidification microstructure of the initial alloy band is as follows: Figure 26 As shown, it includes a main component of approximately Fe. 99 La1 has a black, dispersed dendritic phase, and its main component is approximately Fe. 64 Hf 35 The initial alloy melt contains white, dispersed dendritic phases of La1 and a matrix phase primarily composed of La. Therefore, Hf in the initial melt cannot dissolve into the iron-rich phase during solidification; it precipitates only as Fe2Hf intermetallic compounds. The Fe-rich phase, however, primarily precipitates as Fe. 99 La1 precipitates as a dispersed dendritic phase. Neither of the two dendritic phases can produce spherical grains. Therefore, the addition of Hf to La-Fe alloys cannot produce iron-rich spherical grains.

[0356] Comparative Example 4

[0357] Using commercially available La, Fe, and Ta raw materials, according to the nominal component La by atomic percentage 50 Fe 40 Ta 10 The main component of the smelting is La. 50 Fe 40 Ta 10 The initial alloy melt was cooled at a rate of approximately 500 K / s and solidified into an initial alloy band approximately 1 mm thick. The solidification microstructure of the initial alloy band is as follows: Figure 27 As shown, it includes a main component of approximately Fe. 99 La1 has a black, dispersed dendritic phase, and its main component is approximately Fe. 69 Ta 30 La1's white flocculent dendritic phase (such as...) Figure 28The arrows indicate the Fe7Ta3 intermetallic compound and the matrix phase, which is mainly composed of La. Therefore, during solidification, Ta in the initial alloy melt cannot dissolve into the iron-rich phase and can only precipitate as the Fe7Ta3 intermetallic compound. The Fe-rich phase, however, primarily precipitates as Fe. 99 La1 precipitates as a dispersed dendritic phase. Neither of the two dendritic phases can produce spherical grains. Therefore, the addition of Ta to La-Fe alloys cannot produce iron-rich spherical grains.

[0358] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0359] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for preparing spherical iron alloy powder material, characterized in that, It includes the following steps: Step 1: Select initial alloy raw materials and melt them according to the initial alloy composition ratio to obtain a homogeneous initial alloy melt; the main component of the initial alloy melt is La. x Fe y T z M a D b Where T contains at least one of Cr and V, M contains at least one of Al, Ni, Co, and Si, D contains at least one of Mo, W, and Ti, and x, y, z, a, and b represent the atomic percentage content of the corresponding constituent elements, with 18%≤x≤95.8%, 4%≤y≤81.8%, 0.1%≤z≤35%, 0≤a≤40%, and 0≤b≤15%. Step two involves solidifying the initial alloy melt into an initial alloy solid using rapid solidification technology. The solidified structure of the initial alloy solid comprises a matrix phase and a dispersed particulate phase. The melting point of the matrix phase is lower than that of the dispersed particulate phase, and the dispersed particulate phase is encapsulated within the matrix phase. The volume percentage of the matrix phase in the solidified structure is not less than 40%. The average composition of the matrix phase is primarily La. x1 M a1 The dispersed particulate phase is mainly composed of Fe. y2 T z2 M a2 D b2 La x2 Where x1, a1, x2, y2, z2, a2, and b2 represent the atomic percentage content of the corresponding constituent elements, and 45%≤x1≤100%, 0%≤a1≤55%, 50%≤y2≤98%, 0.2%≤z2<50%, 0%≤a2≤30%, 0%≤b2≤35%, 0%≤x1≤100%, 0%≤y2≤98%, 0 ...≤30%, 0%≤y2≤35%, 0%≤x1≤100%, 0%≤y2≤35%, 0%≤x1≤100%, 0%≤y2≤35%, 0%≤x1≤100%, 0%≤y2≤35%, <x2≤5%; The dispersed particle phase is mainly spherical or near-spherical in shape; the volume percentage of the spherical or near-spherical dispersed particle phase in all dispersed particle phases is greater than 50%; protruding short dendrites grow on some of the spherical or near-spherical dispersed particle phases, which makes the entire spherical or near-spherical dispersed particle phase have shape characteristics similar to "coronavirus"; the particle size of the dispersed particle phase is 5nm~50μm. Step 3: Remove the matrix phase from the initial alloy solid and mainly retain the dispersed particle phase, thus obtaining a product whose main component is Fe. y2 T z2 M a2 D b2 La x2 Ferroalloy powder material; wherein, 50%≤y2≤98%, 0.2%≤z2<50%, 0%≤a2≤30%, 0%≤b2≤35%, 0 <x2≤5%; The ferroalloy powder particles are mainly spherical or near-spherical in shape; the volume percentage of the spherical or near-spherical ferroalloy powder particles in all ferroalloy powders is greater than 50%; some spherical or near-spherical ferroalloy powder particles have protruding short dendrites growing on them, which gives the entire spherical or near-spherical ferroalloy powder particles a shape similar to a "coronavirus"; the particle size of the ferroalloy powder particles is 5nm~50μm.

2. The method for preparing spherical iron alloy powder material according to claim 1, characterized in that, The number of the protruding short dendrites is one or more, and the length of the further protrusion from the spherical surface is less than half the radius of the spherical particle.

3. The method for preparing spherical iron alloy powder material according to claim 1, characterized in that, The initial alloy melt in step one further includes non-metallic impurity elements, which include at least one of O, N, H, P, S, and Cl; the atomic percentage content of the non-metallic impurity elements in the initial alloy melt is greater than 0 and less than 10%; during the formation of the dispersed particle phase in step two, the non-metallic impurity elements are enriched in the La-rich matrix phase, thereby purifying the dispersed particle phase, i.e., the atomic percentage content of the non-metallic impurity elements in the dispersed particle phase is lower than the atomic percentage content of the non-metallic impurity elements in the initial alloy melt; and the atomic percentage content of the non-metallic impurity elements in the dispersed particle phase is less than 1.5%; and the content of non-metallic impurity elements in the spherical or near-spherical iron alloy powder particles in step three is also lower than the content of non-metallic impurity elements in the initial alloy melt.

4. A spherical iron alloy powder material, characterized in that, Prepared by the method for preparing spherical iron alloy powder material according to any one of claims 1-3; Some characteristics of the spherical iron alloy powder material include: the main component of the spherical iron alloy powder material is Fe. y2 T z2 M a2 D b2 La x2 Among them, 50%≤y2≤98%, 0.2%≤z2<50%, 0%≤a2≤30%, 0%≤b2≤35%, 0 <x2≤5%; The ferroalloy powder particles are mainly spherical or near-spherical in shape; the volume percentage of the spherical or near-spherical ferroalloy powder particles in all ferroalloy powders is greater than 50%; some spherical or near-spherical ferroalloy powder particles have protruding short dendrites growing on them, which makes the entire spherical or near-spherical ferroalloy powder particles have shape characteristics similar to "coronavirus". The T contains at least one of Cr and V, the M contains at least one of Al, Ni, Co and Si, and the D contains at least one of Mo, W and Ti; x1, a1, x2, y2, z2, a2 ​​and b2 represent the atomic percentage content of the corresponding constituent elements.

5. A method for preparing a high-silicon-content spherical iron-chromium-silicon powder material, characterized in that, The spherical iron alloy powder material with Fe-Cr as the main constituent element or the spherical iron alloy powder material with low Si content and Fe-Cr-Si as the main constituent element prepared in steps one to three of claim 1 is subjected to Si infiltration treatment to obtain a spherical powder material with high Si content and Fe-Cr-Si as the main constituent element.

6. The method for preparing high-silicon-content spherical iron-chromium-silicon powder material according to claim 5, characterized in that, According to Step 1 and Step 2 described in Claim 1, prepare the initial alloy solid described in Step 2 of Claim 1; wherein, T contains Cr, M contains Si, 0 < a ≤ 40%; the average composition of the matrix phase is mainly La x1 Si a1 ; the composition of the dispersed particle phase is mainly Fe with a low Si content y2 Cr z2 Si a2 D b2 La x2 ; for the La x1 Si a1 in the matrix phase, Si is combined with La in the form of intermetallic compounds; 0 < a2 ≤ 8%; use a dilute acid solution to remove La in the initial alloy solid x1 Si a1 Remove La in the matrix phase through dealloying reaction, while retaining the original La x1 Si a1 in the matrix phase, to obtain a composite powder of nanoporous Si and the Fe y2 Cr z2 Si a2 D b2 La x2 particles with a low Si content; use the nanoporous Si as a Si source to perform Si infiltration on the Fe y2 Cr z2 Si a2 D b2 La x2 particles with a low Si content, and then a spherical Fe-Cr-Si powder material with a high Si content can be obtained, whose composition is mainly Fe y3 Cr z3 Si a3 D b3 La x3 ; where x3, y3, z3, a3, b3 respectively represent the atomic percentage contents of the corresponding constituent elements, and 0 < y3 < y2, 0 < z3 < z2, 0 < a2 < a3, 0 ≤ b3 ≤ b2, 0 < x3 < x2 7. A high-silicon-content spherical iron-chromium-silicon powder material, characterized in that, The high-silicon-content spherical iron-chromium-silicon powder material is prepared by the method described in claim 5.

8. A composite powder of nanoporous Si and spherical Fe-Cr-Si particles, characterized in that, Nanoporous Si and low-Si-content Fe were prepared by the method described in claim 6. y2 Cr z2 Si a2 D b2 La x2 The composite powder of particles is a composite powder of nanoporous Si and spherical Fe-Cr-Si particles.

9. A method for preparing high-nickel content iron-chromium-nickel powder metallurgy products, characterized in that, Includes the following steps: Step 1, prepare the initial alloy solid described in Step 2 of Claim 1 according to Step 1 and Step 2 of Claim 1; wherein, T contains Cr, M contains Ni, 0 < a ≤ 40%; the average composition of the matrix phase is mainly La x1 Ni a1 ; the composition of the dispersion particle phase is mainly Fe with a low Ni content y2 Cr z2 Ni a2 D b2 La x2 ; the La x1 Ni a1 in the matrix phase is combined with La in the form of an intermetallic compound; 0 < a2 ≤ 12%; Step 2, the initial alloy solid La is reacted with a dilute acid solution. x1 Ni a1 La in the matrix phase is removed via a dealloying reaction, while preserving the original La content. x1 Ni a1 Most of the Ni in the matrix phase is not removed by the reaction, resulting in nanoporous Ni and low-Ni-content Fe. y2 Cr z2 Ni a2 D b2 La x2 Composite powders of particles; Step 3, mix nanoporous Ni with the low-Ni content Fe y2 Cr z2 Ni a2 D b2 La x2 The composite powder particles are pressed into shape and then heat-treated and sintered to obtain high-Ni content iron-chromium-nickel powder metallurgy products, whose main component is Fe. y3 Cr z3 Ni a3 D b3 La x3 Where x3, y3, z3, a3, and b3 represent the atomic percentage content of the corresponding constituent elements, and 0 <y3<y2,0<z3<z2,0<a2<a3,0≤b3≤b2,0<x3<x2。 10. A high-nickel content iron-chromium-nickel powder metallurgy product, characterized in that, The high-nickel content iron-chromium-nickel powder metallurgy product is prepared by the method described in claim 9.

11. A composite powder of nanoporous Ni and low-Ni content iron-chromium-nickel particles, characterized in that, Prepared by steps 1 and 2 of the method described in claim 9.

12. The application of the spherical iron alloy powder material according to claim 4 in any of the following fields, including ordinary powder metallurgy, metal injection molding (MIM), 3D printing, magnetic materials, heat-resistant materials, high-temperature alloys, coatings, and microwave absorbing materials.

13. The application of the spherical iron alloy powder material according to claim 4 in the field of electrothermal materials, wherein the main components of the spherical iron alloy powder material include Fe-Cr-Al.

14. The application of the high-silicon-content spherical iron-chromium-silicon powder material according to claim 7 in magnetic materials.

15. The application of the high-nickel content iron-chromium-nickel powder metallurgy product according to claim 10 in high-temperature alloys.

16. An alloy solid, characterized in that, The initial alloy solid is prepared by the method described in steps one and two of claim 1; its specific features include, Prepared by including the following steps: Select initial alloy raw materials and melt them according to the initial alloy composition ratio to obtain a homogeneous initial alloy melt; the main component of the initial alloy melt is La. x Fe y T z M a D b Where T contains at least one of Cr and V, M contains at least one of Al, Ni, Co, and Si, D contains at least one of Mo, W, and Ti, and x, y, z, a, and b represent the atomic percentage content of the corresponding constituent elements, with 18%≤x≤95.8%, 4%≤y≤81.8%, 0.1%≤z≤35%, 0≤a≤40%, and 0≤b≤15%. An initial alloy melt is solidified into an initial alloy solid using a rapid solidification technique. The solidified microstructure of the initial alloy solid comprises a matrix phase and a dispersed particulate phase. The melting point of the matrix phase is lower than that of the dispersed particulate phase, and the dispersed particulate phase is encapsulated within the matrix phase. The volume percentage of the matrix phase in the solidified microstructure is not less than 40%. The average composition of the matrix phase is primarily La. x1 M a1 The dispersed particulate phase is mainly composed of Fe. y2 T z2 M a2 D b2 La x2 Where x1, a1, x2, y2, z2, a2, and b2 represent the atomic percentage content of the corresponding constituent elements, and 45%≤x1≤100%, 0%≤a1≤55%, 50%≤y2≤98%, 0.2%≤z2<50%, 0%≤a2≤30%, 0%≤b2≤35%, 0%≤x1≤100%, 0%≤y2≤98%, 0 ...≤30%, 0%≤y2≤35%, 0%≤x1≤100%, 0%≤y2≤35%, 0%≤x1≤100%, 0%≤y2≤35%, 0%≤x1≤100%, 0%≤y2≤35%, <x2≤5%; The dispersed particle phase is mainly spherical or near-spherical in shape; the volume percentage of the spherical or near-spherical dispersed particle phase in all dispersed particle phases is greater than 50%; protruding short dendrites grow on some of the spherical or near-spherical dispersed particle phases, which makes the entire spherical or near-spherical dispersed particle phase have shape characteristics similar to "coronavirus"; the particle size of the dispersed particle phase is 5nm~50μm.

17. The application of the spherical iron alloy powder material according to claim 4 in the field of magnetohydrodynamics.

18. The application of the spherical iron alloy powder material according to claim 17 in the field of magnetohydrodynamics, characterized in that, It includes the following steps: mixing the spherical ferroalloy powder, the carrier liquid and the surfactant evenly to obtain the ferrofluid; some characteristics of the spherical ferroalloy powder material include: the main component of the spherical ferroalloy powder material is Fe y2 T z2 M a2 D b2 La x2 ; wherein, 50% ≤ y2 ≤ 98%, 0.2% ≤ z2 < 50%, 0% ≤ a2 ≤ 30%, 0% ≤ b2 ≤ 35%, 0 < x2 ≤ 5%; 1% ≤ z2 + b2 < 50%; the shape of the ferroalloy powder particles is mainly spherical or near-spherical; the volume percentage content of the spherical or near-spherical ferroalloy powder particles in all the ferroalloy powders is greater than 50%; some spherical or near-spherical ferroalloy powder particles grow convex-shaped short dendrites, which make the whole spherical or near-spherical ferroalloy powder particles have the shape characteristics similar to the "coronavirus". The particle size of the ferroalloy powder is 5nm~100nm; T contains at least one of Cr and V, M contains at least one of Al, Ni, Co and Si, and D contains at least one of Mo, W and Ti; x1, a1, x2, y2, z2, a2 ​​and b2 represent the atomic percentage content of the corresponding constituent elements.

19. A coronavirus-like spherical ferroalloy powder particle, characterized by: The main component of the coronavirus-shaped spherical ferroalloy powder particles is Fe y2 T z2 M a2 D b2 La x2 ; wherein, 50% ≤ y2 ≤ 98%, 0.2% ≤ z2 < 50%, 0% ≤ a2 ≤ 30%, 0% ≤ b2 ≤ 35%, 0 < x2 ≤ 5%; T includes at least one of Cr and V, M includes at least one of Al, Ni, Co, and Si, D includes at least one of Mo, W, and Ti, La is rare earth La, and La mainly exists in solid solution in the coronavirus-shaped spherical ferroalloy particles with the main component being Fe y2 T z2 M a2 D b2 La x2 ; x1, a1, x2, y2, z2, a2, and b2 respectively represent the atomic percentage contents of the corresponding constituent elements; the coronavirus-shaped spherical ferroalloy powder particles include a main body part and an attached body part; wherein, the main body part is a spherical or nearly spherical sphere, and the attached body part is a plurality of protrusions that grow in-situ on the surface of the sphere of the main body part; the spherical ferroalloy powder particles have a shape similar to that of a coronavirus, and the plurality of protrusions of the attached body part correspond to the plurality of corona protrusions of the coronavirus shape; the diameter of the sphere of the main body part of the coronavirus-shaped spherical ferroalloy powder particles is 20 nm to 50 μm, and the height of the protrusions of the attached body part is less than 0.3 times the diameter of the sphere of the main body part.

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