Nano-diamond particle permeation reinforced iron-based metal powder and preparation method thereof

Abstract

The invention discloses nano-diamond particle infiltration reinforced iron-based metal powder and a preparation method thereof.The preparation method comprises the steps that iron-based metal powder and nano-diamond particles are mixed, and the nano-diamond particles are evenly distributed on the surface of the single iron-based metal powder; the addition amount of the nano-diamond particles accounts for 0.1%-5% of the mass of the iron-based metal powder; and the mixed powder is subjected to heat treatment under the vacuum and / or argon protection condition, and the nano-diamond particle infiltration reinforced iron-based metal powder is prepared. According to the method, nano-diamond particles are effectively permeated into the iron-based metal powder, and the technical problems that in the prior art, nano-diamond is prone to agglomeration and graphitization when dispersed in a metal matrix, and the bonding strength of the nano-diamond and the matrix is low are solved.

Description

Technical Field

[0001] The invention belongs to the technical field of powder metallurgy and metal powder processing for 3D printing, and relates to an iron-based metal powder infiltrated and strengthened by nano-diamond particles and a preparation method thereof. Background Art

[0002] In modern manufacturing, powder metallurgy and metal 3D printing technologies have attracted widespread attention due to their ability to manufacture complex structures and save materials. Powder metallurgy precisely manufactures parts by pressing and sintering metal powders, while metal 3D printing achieves complex designs by stacking them layer by layer. These technologies have shown great potential in high-tech fields such as aerospace, automobile manufacturing, and medical devices, and are particularly suitable for manufacturing parts with complex shapes and fine structures. Whether it is powder metallurgy or metal 3D printing, the mechanical properties of the material are still the key factors affecting the quality of the final product and the scope of application. Nanomaterials have excellent physical and chemical properties and can significantly improve the mechanical properties and wear resistance of metals. Therefore, researchers are constantly exploring ways to introduce nanomaterials into metal matrices to improve the mechanical properties and application scope of the materials.

[0003] Nanodiamond is considered to be an ideal nano-reinforcement phase material due to its excellent mechanical properties (such as high hardness and high elastic modulus) and chemical stability. However, nanodiamond faces several key problems in practical applications: Agglomeration problem: Nanodiamond has a high surface energy and is prone to agglomeration during the dispersion process, forming large-sized agglomerates, resulting in uneven dispersion and affecting its reinforcement effect; Graphitization problem: During high-temperature treatment, nanodiamond is prone to graphitization and transformation into a graphite structure, thereby losing its original excellent properties; Bonding strength problem: The bonding strength between nanodiamond and the metal matrix is ​​low, and it is easy to fall off during use, affecting the overall performance of the material.

[0004] In order to overcome these problems, traditional methods such as surface modification, coating and chemical vapor deposition are used to improve the dispersion and stability of nanodiamonds, but these methods are often complex, costly and difficult to achieve large-scale production. Therefore, a simple and effective method is urgently needed to solve the above problems and achieve uniform distribution and firm bonding of nanodiamonds in metal matrix. Summary of the invention

[0005] In view of the problems existing in the prior art, the present invention provides a nano-diamond particle infiltrated iron-based metal powder and a preparation method thereof, thereby solving the technical problems in the prior art that nano-diamonds are easy to agglomerate and graphitize when dispersed in a metal matrix and have low bonding strength with the matrix.

[0006] The present invention is achieved through the following technical solutions: A method for preparing nano-diamond particle infiltration-reinforced iron-based metal powder comprises the following steps: S1: mixing iron-based metal powder and nano-diamond particles so that the nano-diamond particles are evenly distributed on the surface of a single iron-based metal powder; the amount of the nano-diamond particles added is 0.1% to 5% of the mass of the iron-based metal powder; S2: heat-treating the mixed powder under vacuum or argon protection conditions to obtain nano-diamond particle infiltrated iron-based metal powder.

[0007] Preferably, the particle size of the iron-based metal powder is 5 to 150 microns.

[0008] Preferably, the particle size of the nano-diamond particles is 5 to 100 nanometers.

[0009] Preferably, the added amount of the nano-diamond particles accounts for 3% of the mass of the iron-based metal powder.

[0010] Preferably, the heat treatment temperature is 850-1000° C. and the time is 30-180 min.

[0011] Preferably, the powder mixing method is powder mixing by a mixer or powder mixing by freeze drying.

[0012] Preferably, when the mixer is used to mix the powder, the speed of the mixer is 5 to 50 rpm and the mixing time is 5 to 60 min.

[0013] Preferably, when the freeze-drying method is used to mix the powders, the iron-based metal powder and the aqueous dispersion of nano-diamond particles are fully mixed and then freeze-dried at -60 to -10°C for 5 to 24 hours.

[0014] Preferably, when the mixed powder is heat treated under vacuum conditions, the vacuum degree is 10 -3 ~10 -1 pa.

[0015] A nano-diamond particle infiltrated and reinforced iron-based metal powder is prepared by the above method.

[0016] Compared with the prior art, the present invention has the following beneficial technical effects: The invention discloses a preparation method of nano-diamond particle infiltration reinforced iron-based metal powder. The nano-diamond particles are evenly distributed on the surface of a single iron-based metal powder by a powder mixing method, thereby avoiding the agglomeration of the nano-diamond particles. The nano-diamond particles are heat-insulated at high temperature. Since there is a large surface energy difference between the iron matrix and the diamond surface, the capillary force generated between the two surfaces enables the diamond particles to self-drive into the interior of the iron-based metal sphere, thereby achieving effective penetration of the diamond particles, greatly reducing the direct contact between the diamond particles and the air, thereby inhibiting graphitization, and significantly improving the strength of the material as a nano-reinforced phase. , hardness and wear resistance; and will not agglomerate or enrich at the grain boundaries during 3D printing, avoiding deterioration of the mechanical properties of the printed material; the amount of nano-diamond particles added in the present invention accounts for 0.1% to 5% of the mass of the iron-based metal powder. Within this amount range, the nano-diamond particles can be evenly distributed in the iron-based metal powder, effectively avoiding large-scale agglomeration of nano-diamond particles, forming an effective strengthening phase, and excessive addition of nano-diamond particles will lead to agglomeration and enrichment between particles, ensuring uniform distribution of nano-diamond particles in the iron-based metal powder, and improving the mechanical properties of the iron-based metal powder. Therefore, the present invention allows the nano-diamond particles to penetrate into the interior of the iron-based metal powder, avoiding the problem that the nano-diamond is easy to agglomerate when dispersed in the metal matrix, and is easy to graphitize during heat treatment.

[0017] Furthermore, the particle size of the iron-based metal powder is 5 to 150 microns. First, the iron-based metal powder with a particle size within this range has good fluidity, which is convenient for uniform and continuous transportation and deposition during the 3D printing process. Good fluidity helps to ensure close bonding between the printed layers and improve the density and strength of the printed parts. The iron-based metal powder with a moderate particle size can more accurately control the thickness and shape of the printed layer, thereby achieving higher printing accuracy, which helps to print complex and fine structures to meet the manufacturing needs of high-performance parts and components. In the powder mixing process, the iron-based metal powder particles of 5 to 150 microns can be more effectively mixed with the nano-diamond particles to ensure the uniform distribution of the diamond particles on the powder surface. The uniform distribution helps to achieve uniform penetration of the diamond particles during the heat treatment process, further improving the performance of the material.

[0018] Furthermore, the particle size of the nano-diamond particles is 5 to 100 nanometers, which can enable the diamond particles to obtain a better surface strengthening effect. The particle size range of 5 to 100 nanometers enables the nano-diamond particles to effectively penetrate into the interior of the iron-based metal powder to form a uniform strengthening phase, thereby improving the overall performance of the printed part; in addition, the nano-diamond particles themselves have extremely high hardness, and introducing them into the iron-based metal powder as a strengthening phase can significantly improve the hardness of the material.

[0019] Furthermore, the heat treatment temperature is 850-1000°C and the time is 30-180 min. Within this temperature range, the interface reaction between the diamond particles and the iron powder can be fully carried out, which helps to form a strong interface bond. This bond not only enhances the stability of the diamond particles in the iron powder, but also improves the overall strength and hardness of the material. The heat treatment at high temperature helps to adjust the internal microstructure of the iron powder, providing more favorable conditions for the infiltration of diamond particles. In addition, within this temperature range, the oxidation rate of the iron powder surface can be effectively reduced by reasonable heat treatment time control. Although a longer heat treatment time is conducive to the infiltration of diamond particles, it may also increase the risk of oxidation. However, under this setting, the dual goals of diamond particle infiltration and reduced oxidation can be achieved through precise temperature and time control.

[0020] Furthermore, the powder mixing method is mixing powder with a mixer; when the mixer is mixing powder, the rotation speed of the mixer is 5 to 50 rpm, and the mixing time is 5 to 60 min. Within this rotation speed and mixing time range, the mixer can effectively and evenly disperse the diamond particles in the iron powder. This uniform particle distribution helps to achieve effective penetration and strengthening of the diamond particles in the subsequent heat treatment process. The appropriate rotation speed and mixing time help to break the agglomeration between the diamond particles and prevent them from forming large agglomerates in the iron powder, which helps to ensure the uniform distribution of the diamond particles in the iron powder and further improve the performance of the material.

[0021] Furthermore, the powder mixing method is freeze-drying powder mixing; when the freeze-drying powder mixing method is used, the iron-based metal powder and the aqueous dispersion of nano-diamond particles are fully mixed, and then freeze-dried at -60~-10°C for 5~24 hours. The freeze-drying method uses ice crystals formed by water molecules in a frozen state as carriers to evenly disperse the nano-diamond particles in the iron-based metal powder. The sublimation process of the ice crystals will not destroy the original structure of the particles, thereby ensuring that the diamond particles and the iron powder are fully mixed and evenly distributed. The traditional powder mixing method may cause the agglomeration of the nano-diamond particles and affect the mixing uniformity. The freeze-drying method effectively avoids the occurrence of agglomeration through the sublimation process of the ice crystals, so that the diamond particles are more evenly dispersed in the iron powder.

[0022] Furthermore, when the mixed powder is heat treated under vacuum conditions, the vacuum degree is 10 -3 ~10 -1 In a vacuum environment, due to the extremely low oxygen content, the interface reaction between diamond particles and iron powder will not be disturbed by oxidation, which helps the smooth progress of the interface reaction and promotes the effective penetration of diamond particles; in addition, in a high vacuum environment, the oxygen content is extremely low, which significantly reduces the risk of oxidation on the surface of the iron powder. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0024] Figure 1 It is a schematic flow chart of a method for preparing nano-diamond particle infiltration-reinforced iron-based metal powder in the present invention; Figure 2 The macroscopic photos of original iron powder, diamond powder, iron powder coated with nano-diamond and iron powder infiltrated with nano-diamond particles are shown in Figure 1, where (a) is original iron powder, (b) is diamond powder, (c) is iron powder coated with nano-diamond and (d) is iron powder infiltrated with nano-diamond particles. Figure 3 The following are scanning electron microscope images of original iron powder, iron powder coated with nano-diamonds, and iron powder infiltrated with nano-diamond particles, where (a) is original iron powder, (b) is iron powder coated with nano-diamonds, and (c) is iron powder infiltrated with nano-diamond particles. DETAILED DESCRIPTION

[0025] In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.

[0026] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0027] In this article, all features such as values, quantities, contents and concentrations defined in the form of numerical ranges or percentage ranges are for simplicity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to have included and specifically disclosed all possible secondary ranges and individual values ​​within the range (including integers and fractions).

[0028] In this document, unless otherwise specified, “includes,” “including,” “contains,” “has,” or similar terms cover the meanings of “consisting of” and “mainly consisting of,” for example, “A includes a” covers the meanings of “A includes a and other” and “A only includes a.”

[0029] In this document, in order to make the description concise, not all possible combinations of various technical features in various embodiments or examples are described. Therefore, as long as there is no contradiction in the combination of these technical features, the various technical features in various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered to be within the scope of this specification.

[0030] The present invention provides a method for preparing nano-diamond particle infiltration-reinforced iron-based metal powder, comprising the following steps: S1: Mixing iron-based metal powder with a particle size of 5 to 150 microns and diamond particles with a particle size of 5 to 100 nanometers to make nano-diamond particles evenly distributed on the surface of a single iron-based metal powder; then sieving through a 50 to 300 mesh sieve in turn to remove coarse particles and maintain uniform particle size; the amount of the nano-diamond particles added is 0.1% to 5% of the mass of the iron-based metal powder; more preferably, the amount of the nano-diamond particles added is 3% of the mass of the iron-based metal powder.

[0031] The powder mixing method is mixing powder by a mixer or mixing powder by freeze drying; when mixing powder by a mixer, the speed of the mixer is 5 to 50 rpm, and the mixing time is 5 to 60 min. When mixing powder by freeze drying, the iron-based metal powder and the aqueous dispersion of nano-diamond particles are fully mixed, and then freeze-dried at -60 to -10°C for 5 to 24 h. The above-mentioned powder mixing process is crucial, as it allows the diamond particles to be evenly dispersed on the surface of the iron-based metal powder.

[0032] S2: heat treating the mixed powder at 850-1000°C for 30-180 min under vacuum or argon protection conditions to obtain nano-diamond particle infiltrated iron-based metal powder.

[0033] In a preferred embodiment, when the mixed powder is heat treated under vacuum conditions, the vacuum degree is 10 -3 ~10 - 1 pa.

[0034] When the mixed powder is heat treated under argon protection, the vacuum degree is 10 4 ~10 5 Pa, the pressure of the system can be considered to be 10 4 ~10 5 pa, under the protection of argon, the interference of oxygen is avoided during the heat treatment process, which is helpful to form a stronger interface bond between the diamond particles and the iron powder. This interface bond is crucial to improving the overall strength and hardness of the material; in addition, argon, as an inert gas, can effectively isolate the oxygen in the air, thereby reducing the oxidation rate of the iron powder surface.

[0035] In addition, the present invention also discloses nano-diamond particle infiltration reinforced iron-based metal powder prepared by the above method, wherein the nano-diamond particles are evenly distributed on the surface of a single iron-based metal powder by a powder mixing method to avoid agglomeration; after being kept at high temperature for a period of time, the diamond particles can be self-driven into the interior of the iron-based metal sphere, evenly distributed inside the sphere and maintain a diamond structure; during the 3D printing process, the diamond particles will not agglomerate or be enriched at the grain boundaries to avoid deterioration of the mechanical properties of the printed material; the nano-diamonds entering the interior of the iron-based metal sphere are inhibited from graphitization during the 3D printing process, and still mostly maintain a diamond structure, and as a nano-reinforced phase, the strength, hardness and wear resistance of the material are significantly improved; the nano-diamond reinforced iron powder of the present invention is suitable for 3D printing to prepare high-performance steel materials and iron-containing high-entropy alloys.

[0036] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0037] The following examples use conventional instruments and equipment in the art. The experimental methods in the following examples where specific conditions are not specified are usually carried out under conventional conditions or under conditions recommended by the manufacturer. The various raw materials used in the following examples are conventional commercial products unless otherwise specified, and their specifications are conventional specifications in the art. In the specification of the present invention and the following examples, unless otherwise specified, "%" means weight percentage, "part" means weight part, and ratio means weight ratio.

[0038] Example 1 A method for preparing nano-diamond particle infiltration-reinforced iron-based metal powder, the preparation method is as follows: Pure iron powder with a diameter of 35 microns and 0.5 wt.% of diamond particles with a particle size of 50 nanometers were mixed in a three-dimensional motion mixer at a speed of 50 rpm for 20 minutes. The resulting mixed powder was sieved through 50, 100, and 200 mesh sieves in turn, and the nano-diamond particles were evenly distributed on the surface of a single iron-based metal powder. The mixed powder was sieved for 10 -3 Under the condition of argon protection and keeping at 950 ℃ for 120 minutes, the powder was cooled with the furnace to obtain a metallic iron-based powder with uniformly dispersed nano-diamond particles infiltrated into the iron-based spheres.

[0039] Example 2 A method for preparing nano-diamond particle infiltration-reinforced iron-based metal powder, the preparation method is as follows: Pure iron powder with a diameter of 75 microns and 1 wt.% of diamond particles with a particle size of 20 nanometers were mixed in a three-dimensional motion mixer at a speed of 30 rpm for 40 minutes. The resulting mixed powder was sieved through 100, 180, and 250 mesh sieves in turn, and the nano-diamond particles were evenly distributed on the surface of a single iron-based metal powder. - 1 Under the condition of argon protection and keeping at 850 ℃ for 180 minutes, the powder was cooled with the furnace to obtain a metallic iron-based powder with uniformly dispersed nano-diamond particles infiltrated into the iron-based sphere.

[0040] Example 3 A method for preparing nano-diamond particle infiltration-reinforced iron-based metal powder, the preparation method is as follows: Pure iron powder with a diameter of 120 microns and 3 wt.% diamond particles with a particle size of 100 nanometers were mixed in a three-dimensional motion mixer at a speed of 20 rpm for 60 minutes. The resulting mixed powder was sieved through 100, 160, and 300 mesh sieves in turn, and the nano-diamond particles were evenly distributed on the surface of a single iron-based metal powder. 5 Under the condition of argon protection and keeping at 980 ℃ for 60 minutes, the powder was cooled with the furnace to obtain a metallic iron-based powder with uniformly dispersed nano-diamond particles infiltrated into the iron-based sphere.

[0041] Example 4 A method for preparing nano-diamond particle infiltration-reinforced iron-based metal powder, the preparation method is as follows: 1 wt.% of diamond particles with a particle size of 50 nanometers were fully dissolved in water, and then pure iron powder with a diameter of 120 micrometers was added to the diamond aqueous solution and stirred evenly. The mixture was kept at -50 °C for 10 hours to remove moisture. The obtained mixed powder was sieved through 100, 160, and 300 mesh sieves in turn. The nano-diamond particles were evenly distributed on the surface of a single iron-based metal powder. The mixed powder was sieved for 10 5 The sample was kept at 980 °C for 60 min under argon protection and then cooled with the furnace.

[0042] Comparative Example 1 A nano-diamond coated iron powder, the preparation method of which is as follows: Pure iron powder with a diameter of 35 microns and 0.5 wt.% of diamond particles with a particle size of 50 nanometers were mixed in a three-dimensional motion mixer at a rotation speed of 50 rpm for 20 minutes. The obtained mixed powder was sieved through 50, 100, and 200 mesh sieves in turn to prepare nano-diamond-coated iron powder.

[0043] Figure 2These are macroscopic photographs of original iron powder, diamond powder, nano-diamond coated iron powder and iron powder infiltrated with nano-diamond particles, where (a) is original iron powder, (b) is diamond powder, (c) is nano-diamond coated iron powder, and (d) is iron powder infiltrated with nano-diamond particles. It can be seen from the figure that there is no obvious change in color among the original iron powder, nano-diamond coated iron powder and iron powder infiltrated with nano-diamond particles, indicating that there is no obvious oxidation on the surface of the iron powder infiltrated with nano-diamond particles, and it can be used as metal powder for powder metallurgy and 3D printing.

[0044] Figure 3 The figures are scanning electron microscope images of original iron powder, nano-diamond coated iron powder and iron powder infiltrated with nano-diamond particles, wherein (a) is original iron powder; (b) nano-diamond coated iron powder is the sample prepared in Comparative Example 1; (c) iron powder infiltrated with nano-diamond particles is the sample prepared in Example 1. It can be seen from the figure that the nano-diamond particles in Comparative Example 1 are dispersed on the surface of a single iron powder, while in the iron powder infiltrated with nano-diamond particles prepared in Example 1 of the present invention, the surface of the diamond particles is smooth and the sphericity is good, indicating that most of the nano-diamond particles have successfully entered the interior of the iron ball.

[0045] Table 1 shows the normalized atomic percentages of the original iron powder, the iron powder coated with nano-diamond (Comparative Example 1), and the iron powder infiltrated with nano-diamond particles (Example 1). As can be seen from the table, the carbon content in Example 1 is significantly lower than that in Comparative Example 1, and the oxygen content is not much different, indicating that the nano-diamond particles have successfully infiltrated into the iron powder, and there is no obvious oxidation on the surface of the iron powder infiltrated with nano-diamond particles.

[0046] Table 1 Normalized atomic percentage of original iron powder, nano-diamond coated iron powder (Comparative Example 1) and iron powder infiltrated with nano-diamond particles (Example 1)

[0047] Example 5 The present invention provides a method for preparing nano-diamond particle infiltration-reinforced iron-based metal powder, comprising the following steps: S1: Mixing iron-based metal powder with a particle size of 5 microns and diamond particles with a particle size of 5 nanometers to make the nano-diamond particles evenly distributed on the surface of a single iron-based metal powder; then sieving through 50 mesh, 100 mesh, and 180 mesh sieves in turn to remove coarse particles and keep the particle size uniform; the addition amount of the nano-diamond particles accounts for 0.1% of the mass of the iron-based metal powder.

[0048] The powder mixing method is mixing the powder with a mixer, the speed of the mixer is 5 rpm, and the mixing time is 60 min.

[0049] S2: Mix the powder in a vacuum of 10-3 Under vacuum conditions of pa, the nano-diamond particle infiltration-reinforced iron-based metal powder was obtained by heat treatment at 850°C for 180 min.

[0050] In the iron-based metal powder infiltrated and reinforced with nano-diamond particles prepared in this embodiment, the nano-diamond particles evenly penetrate into the interior of the iron-based metal powder to form a reinforcement phase.

[0051] Example 6 The present invention provides a method for preparing nano-diamond particle infiltration-reinforced iron-based metal powder, comprising the following steps: S1: Mixing iron-based metal powder with a particle size of 150 microns and diamond particles with a particle size of 100 nanometers to make the nano-diamond particles evenly distributed on the surface of a single iron-based metal powder; then sieving through 100 mesh, 180 mesh, and 250 mesh sieves in turn to remove coarse particles and keep the particle size uniform; the addition amount of the nano-diamond particles accounts for 3% of the mass of the iron-based metal powder.

[0052] The powder mixing method is mixing the powder with a mixer, the speed of the mixer is 50 rpm, and the mixing time is 5 min.

[0053] S2: The mixed powder is heat treated at 1000° C. for 30 min under argon protection to obtain nano-diamond particle infiltrated iron-based metal powder.

[0054] In the iron-based metal powder infiltrated and reinforced with nano-diamond particles prepared in this embodiment, the nano-diamond particles evenly penetrate into the interior of the iron-based metal powder to form a reinforcement phase.

[0055] Example 7 The difference between this embodiment and embodiment 5 is: The powder mixing method is mixing powder with a mixer, the speed of the mixer is 20 revolutions / min, and the mixing time is 30 minutes, so that the nano-diamond particles are uniformly infiltrated into the iron-based metal powder.

[0056] Example 8 The present invention provides a method for preparing nano-diamond particle infiltration-reinforced iron-based metal powder, comprising the following steps: S1: Mixing iron-based metal powder with a particle size of 80 microns and diamond particles with a particle size of 50 nanometers to make the nano-diamond particles evenly distributed on the surface of a single iron-based metal powder; then sieving through 100 mesh, 160 mesh, and 300 mesh sieves in turn to remove coarse particles and keep the particle size uniform; the addition amount of the nano-diamond particles accounts for 5% of the mass of the iron-based metal powder.

[0057] The powder mixing method is freeze-drying powder mixing, specifically: after the iron-based metal powder and the aqueous dispersion of nano-diamond particles are fully mixed, freeze-drying is performed at -60°C for 5 hours.

[0058] S2: Mix the powder in a vacuum of 10 -1 Under vacuum conditions of 1.5 pa, the nano-diamond particle infiltrated iron-based metal powder was obtained by heat treatment at 900°C for 100 min.

[0059] In the iron-based metal powder infiltrated and reinforced with nano-diamond particles prepared in this embodiment, the nano-diamond particles evenly penetrate into the interior of the iron-based metal powder to form a reinforcement phase.

[0060] Example 9 The difference between this embodiment and embodiment 8 is: The powder mixing method is freeze-drying powder mixing, specifically: after the iron-based metal powder and the aqueous dispersion of nano-diamond particles are fully mixed, freeze-drying at -10°C for 24 hours; In addition, the mixed powder was heat treated at 950°C for 50 min under argon protection to obtain nano-diamond particle-infiltrated iron-based metal powder, achieving uniform infiltration of nano-diamond particles in the iron-based metal powder.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A method for preparing nano-diamond particle infiltration-strengthened iron-based metal powder, characterized in that: The following steps are involved: S1: mixing iron-based metal powder and nano-diamond particles so that the nano-diamond particles are evenly distributed on the surface of a single iron-based metal powder; the amount of the nano-diamond particles added is 0.1% to 5% of the mass of the iron-based metal powder; S2: heat-treating the mixed powder under vacuum or argon protection conditions to obtain nano-diamond particle infiltrated iron-based metal powder.

2. The method for preparing a nano-diamond particle infiltrated iron-based metal powder according to claim 1, characterized in that: The particle size of the iron-based metal powder is 5 to 150 microns.

3. The method for preparing a nano-diamond particle infiltrated iron-based metal powder according to claim 1, characterized in that: The particle size of the nano diamond particles is 5 to 100 nanometers.

4. The method for preparing a nano-diamond particle infiltrated iron-based metal powder according to claim 1, characterized in that: The added amount of the nano-diamond particles accounts for 3% of the mass of the iron-based metal powder.

5. The method for preparing nano-diamond particle infiltrated iron-based metal powder according to claim 1, characterized in that: The heat treatment temperature is 850-1000° C. and the time is 30-180 min.

6. The method for preparing nano-diamond particle infiltrated iron-based metal powder according to claim 1, characterized in that: The powder mixing method is powder mixing by a mixer or powder mixing by freeze drying.

7. The method for preparing nano-diamond particle infiltrated iron-based metal powder according to claim 6, characterized in that: When the mixer is used to mix the powder, the rotation speed of the mixer is 5 to 50 rpm and the mixing time is 5 to 60 min.

8. The method for preparing nano-diamond particle infiltrated iron-based metal powder according to claim 6, characterized in that: When the freeze-drying method is used to mix the powders, the iron-based metal powder and the aqueous dispersion of nano-diamond particles are fully mixed and then freeze-dried at -60 to -10°C for 5 to 24 hours.

9. The method for preparing nano-diamond particle infiltrated iron-based metal powder according to claim 1, characterized in that: When the mixed powder is heat treated under vacuum conditions, the vacuum degree is 10 -3 ~10 -1 pa.

10. A nano-diamond particle infiltrated iron-based metal powder, characterized in that: Prepared by the method according to any one of claims 1 to 9.

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