Amorphous powder and preparation method thereof

Abstract

The present invention provides an amorphous powder without coating process and a preparation method thereof, wherein the surface of the amorphous powder has an anti-rust layer, and the atomic percentage of elements in the amorphous powder is as shown in formula (1): Fe 100‑a‑b‑c‑d‑e‑f‑g B a P b Si c C d Cr e Mn f Nb g (1); where, 74.7≤100‑a‑b‑c‑d‑e‑f‑g≤84.8, 8.7≤a≤18.4, 3.0≤b≤4.5, 0.5≤c≤5.0, 0≤d≤4.0, 0≤e≤2.8, 0.1≤f≤0.5, 0≤g≤2.5; and, 0.15≤b / (b+c)≤0.35.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of amorphous powder preparation, and in particular to an amorphous powder and a preparation method thereof. Background Art

[0002] Magnetic devices are increasingly moving towards miniaturization and high frequency, requiring magnetic materials to possess advantages such as high magnetic permeability, excellent saturation resistance, and ultra-low power loss. As the core component of magnetic devices, magnetic powder cores place higher demands on material selection. Iron-based amorphous materials possess properties such as low magnetocrystalline anisotropy and high resistivity. These properties make iron-based amorphous magnetic powder cores exhibit advantages such as stable magnetic permeability, low loss, and good temperature stability at high frequencies compared to traditional ferrite, iron silicon, and sendust magnetic powder cores. Furthermore, iron-based amorphous magnetic powder cores offer advantages such as low cost and suitability for mass production compared to iron-nickel, iron-nickel-molybdenum, and other magnetic powder cores. Therefore, iron-based amorphous powder has become the material of choice for new high-performance magnetic powder cores.

[0003] Iron-based amorphous powder is mainly prepared by crushing and atomization. The amorphous powder prepared by the crushing method has sharp edges and corners, and the powder is difficult to be coated evenly. In addition, during the pressing process of the magnetic powder core, the sharp corners will pierce the coating layer, resulting in a significant increase in loss. The atomization method for preparing amorphous powder includes gas atomization, water atomization and water-vapor combined atomization. Among them, the gas atomization method can only be used to prepare certain amorphous powders with low Fe content and high amorphous forming ability due to its low specific heat of the cooling medium and low cooling rate; the water-vapor combined atomization equipment is complex, with low production capacity and high cost, and cannot be quickly promoted on a large scale.

[0004] The water atomization method for preparing metal powders uses high-pressure water as the atomizing medium to impact the liquid metal stream. The faster the cooling rate, the lower the cost, the higher the production efficiency, and the wider the composition applicability of the amorphous powder. However, compared to gas atomization and water-gas combined atomization, the metal droplets in the water atomization process do not have time to spheroidize under the action of surface tension before they are cooled and solidified by water. As a result, the particles have poor sphericity and are prone to defects such as satellite balls and burrs, which is not conducive to the back-end coating and pressing processes. In addition, during the subsequent drying process, the water-atomized powder will be fully exposed to water vapor and oxygen at high temperatures, resulting in a sudden increase in the oxygen content of the powder and a reduction in the electromagnetic properties of the powder. Therefore, improving the sphericity of water-atomized amorphous powder and reducing the oxygen content of the powder are of great significance for promoting the industrialization of amorphous alloys. Summary of the Invention

[0005] The embodiments of the present application provide an amorphous powder and a preparation method thereof. The method has high production efficiency and low cost, and the prepared amorphous powder has low oxygen content and good sphericity.

[0006] In a first aspect, an amorphous powder without coating process is provided, wherein the surface of the amorphous powder has an anti-rust layer, and the atomic percentage of elements in the amorphous powder is as shown in formula (1):

[0007] Fe 100-a-b-c-d-e-f-g B a P b Si c C d Cr e Mn f Nb g (1)

[0008] Among them, 74.7≤100-abcdefg≤84.8, 8.7≤a≤18.4, 3.0≤b≤4.5, 0.5≤c≤5.0, 0≤d≤4.0, 0≤e≤2.8, 0.1≤f≤0.5, 0≤g≤2.5;

[0009] Moreover, 0.15≤b / (b+c)≤0.35.

[0010] In one embodiment, the amorphous powder is prepared by water atomization and dried in an atmospheric atmosphere, wherein the oxygen content of the amorphous powder is 100-1000 ppm when the drying is completed.

[0011] In one embodiment, the amorphous powder is placed in a first environment for storage after drying; the temperature of the first environment is 20°C-45°C, and the humidity is 40-85%; wherein, the first oxygen increment of the amorphous powder when stored in the first environment is less than 300ppm; the first oxygen increment is the difference between the oxygen content of the amorphous powder when stored in the first environment for 7 days and the oxygen content of the amorphous powder when the drying is completed; the second oxygen increment of the amorphous powder in the first environment is less than 500ppm; the second oxygen increment is the difference between the oxygen content of the amorphous powder when stored in the first environment for 15 days and the oxygen content of the amorphous powder when the drying is completed.

[0012] In one embodiment, the laser particle size D50 of the amorphous powder is 4-20 μm, and the sphericity is greater than 0.95.

[0013] In one embodiment, the crystallization enthalpy of the amorphous powder is 50-200 J / g.

[0014] In a second aspect, a method for preparing the amorphous powder according to the first aspect is provided, comprising the following steps:

[0015] a) preparing the ingredients according to the atomic percentage of the elements shown in formula (1), and then smelting to obtain a molten alloy;

[0016] b) using atomized water containing a first rust inhibitor to atomize the alloy liquid to obtain the amorphous powder; wherein the mass fraction of the first rust inhibitor in the atomized water is 0.5% to 4%;

[0017] c), drying the amorphous powder;

[0018] in,

[0019] Fe 100-a-b-c-d-e-f-g B a P b Si c C d Cr e Mn f Nb g (1)

[0020] Among them, 74.7≤100-abcdefg≤84.8, 8.7≤a≤18.4, 3.0≤b≤4.5, 0.5≤c≤5.0, 0≤d≤4.0, 0≤e≤2.8, 0.1≤f≤0.5, 0≤g≤2.5;

[0021] Moreover, 0.15≤b / (b+c)≤0.35.

[0022] In one embodiment, the first rust inhibitor is a water-based rust inhibitor.

[0023] In one embodiment, the aqueous rust inhibitor is a long-chain carboxylic acid ester and / or triethanolamine borate.

[0024] In one embodiment, during the water atomization powder making process, the ratio of the flow rate of the atomized water to the alloy liquid is 12-60, and the atomized water pressure is 40-80 MPa.

[0025] In one embodiment, before the alloy liquid is subjected to the water atomization powder making process, the alloy liquid is heated to 250-350° C. above the melting point and kept warm for 20-40 minutes; during the water atomization powder making process, the flow rate of the alloy liquid is 3-15 kg / min.

[0026] In one embodiment, the amorphous powder is dried at 120° C. in an air atmosphere.

[0027] In a third aspect, a use of a rust inhibitor in water atomization powder making is provided.

[0028] In one embodiment, the rust inhibitor is a water-based rust inhibitor.

[0029] In one embodiment, the aqueous rust inhibitor is a long-chain carboxylic acid ester and / or triethanolamine borate.

[0030] The preparation method provided in the embodiment of the present application can add an anti-rust layer to the amorphous powder during the water atomization powder making process, that is, there is no need for a special anti-rust coating process after powder making, so that the surface of the amorphous powder particles can have an anti-rust layer. The anti-rust layer can prevent oxygen, water and other molecules from contacting the amorphous powder during the drying process and the subsequent storage process, thereby reducing the oxygen increment. Therefore, the amorphous powder prepared in the embodiment of the present application can be dried in an atmospheric atmosphere after water atomization powder making, without the need for an inert gas atmosphere. However, the amorphous powder prepared by the prior art needs to be dried in an inert gas atmosphere or vacuum after the water atomization powder making is completed.

[0031] The amorphous powder prepared in the embodiment of the present application can be stored for a long time without undergoing an anti-rust coating process after powder making, and can maintain a low oxygen content and have good sphericity. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the multiple embodiments disclosed in this application, the following is a brief introduction to the drawings required for the description of the embodiments. Obviously, the drawings described below are only the multiple embodiments disclosed in this application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0033] Figure 1 This is a scanning electron microscope (SEM) image of the amorphous powder prepared in Example 1 of the present application;

[0034] Figure 2 This is a SEM scanning electron microscope image of the amorphous powder prepared in Example 2 of the present application;

[0035] Figure 3 This is a SEM image of the amorphous powder prepared in Example 3 of the present application;

[0036] Figure 4 X-ray diffraction (XRD) patterns of the amorphous powders prepared in Examples 1-3 of the present application;

[0037] Figure 5 XRD pattern of the amorphous powder prepared in Comparative Example 1-2 of the present application;

[0038] Figure 6 XRD pattern of the amorphous powder prepared in Comparative Example 3-4 of the present application;

[0039] Figure 7 This is a SEM image of the amorphous powder prepared in Comparative Example 5 of the present application;

[0040] Figure 8 This is a SEM image of the amorphous powder prepared in Comparative Example 6 of the present application;

[0041] Figure 9 This is a SEM scanning electron microscope image of the amorphous powder prepared in Comparative Example 7 of the present application;

[0042] Figure 10 This is a SEM scanning electron microscope image of the amorphous powder prepared in Comparative Example 8 of the present application. DETAILED DESCRIPTION

[0043] To make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be described below with reference to the accompanying drawings in the embodiments of the present invention.

[0044] The present invention provides a method for preparing amorphous powder using a water atomization process. During the water atomization process, a rust-resistant layer can be formed on the surface of the amorphous powder particles. Consequently, during subsequent drying and storage, the rust-resistant layer on the surface of the amorphous powder particles can prevent oxygen, water, and other molecules from contacting the amorphous powder particles, thereby reducing the oxygen content and oxygen gain of the amorphous powder.

[0045] Moreover, in the water atomization process provided in the embodiment of the present application, a large flow rate and low pressure method is adopted, that is, a large atomization water flow rate and a low atomization pressure method is adopted to crush and cool the alloy liquid, thereby improving the sphericity of the amorphous powder particles.

[0046] The amorphous powder preparation method and the prepared amorphous powder provided in the embodiments of the present application are introduced in detail.

[0047] The amorphous powder preparation method of the embodiment of the present application can prepare iron-based amorphous powder. The alloy composition (atomic percentage) of the prepared iron-based amorphous powder is as shown in formula (1).

[0048] Fe 100-a-b-c-d-e-f-g B a P b Si c C d Cr e Mn f Nb g (1)

[0049] Among them, 74.7≤100-abcdefg≤84.8, 8.7≤a≤18.4, 3.0≤b≤4.5, 0.5≤c≤5.0, 0≤d≤4.0, 0≤e≤2.8, 0.1≤f≤0.5, 0≤g≤2.5. Moreover, 0.15≤b / (b+c)≤0.35.

[0050] Fe can increase the saturation magnetization of amorphous powder, but the amorphous forming ability decreases with increasing Fe content. The inventors of this application have found through extensive experiments that when the atomic percentage of Fe is 77.5-83.2, both the saturation magnetization and the amorphous forming ability can be achieved.

[0051] Among non-metallic elements, B, P, Si, and C can enhance the amorphous-forming ability, with B and P having the most significant effects. Furthermore, P can reduce the viscosity of molten steel and improve the sphericity of the powder. Through extensive experiments, the inventors of this application have found that the sphericity of amorphous powder can be improved when the B content is 3.0 ≤ b ≤ 4.5, the P content is 0.5 ≤ c ≤ 5.0, and the ratio of P to B is 0.15 ≤ b / (b + c) ≤ 0.35.

[0052] The addition of Cr can improve the oxidation resistance of amorphous powders, but excessive addition can reduce the saturation magnetization of the amorphous powders. The inventors of this application have found through extensive experiments that an atomic percentage of Cr of 0-2.8 can achieve both the oxidation resistance and saturation magnetization of the amorphous powders.

[0053] The element Mn deoxidizes and desulfurizes molten steel, improving its fluidity and the sphericity of the powder. The inventors of this application have discovered through extensive experiments that an atomic percentage of Mn of 0.1-0.5 can improve the fluidity of molten steel and the sphericity of amorphous powder without affecting other properties of the amorphous powder.

[0054] Nb, as a large-radius atom, can increase the disorder of the system and improve the amorphous-forming ability. The inventors of this application have found through a large number of experiments that when the atomic percentage of Nb is 0-2.5, it can improve the amorphous-forming ability without affecting other properties of the amorphous powder.

[0055] The above section introduces the alloy composition of amorphous powder. Next, we will introduce the overall preparation process of amorphous powder.

[0056] First, prepare the alloy raw materials according to the composition shown in formula (1). Heat the alloy raw materials to melt and keep them at 250-350℃ above the melting point of the alloy for 20-40 minutes to improve the fluidity of the alloy melt.

[0057] During water atomization, the atomizing water flow utilizes high flow and low pressure (i.e., high atomizing water flow and low atomizing pressure) to crush the alloy melt. Specifically, the alloy melt flow rate during the atomization process is 3-15 kg / min, and the water-to-liquid ratio (atomizing water flow rate / alloy melt flow rate) is 12-60. A high water-to-liquid ratio increases the cooling rate and is essential for amorphous formation. While maintaining a stable water flow rate, the atomizing pressure is reduced to 40-80 MPa to improve the sphericity of the powder particles.

[0058] Prior to water atomization, a water-based rust inhibitor is added to the atomized water at a mass fraction of 0.5%-4%. Specifically, the atomized water used in water atomization contains a water-based rust inhibitor at a mass fraction of 0.5%-4%. In one example, the water-based rust inhibitor is a long-chain carboxylate. In another example, the water-based rust inhibitor is triethanolamine borate. In another example, the water-based rust inhibitor is a combination of a long-chain carboxylate and triethanolamine borate. The water-based rust inhibitor forms an anti-rust layer on the surface of the iron-based amorphous powder particles based on the principle that the lone pairs of electrons in the oxygen and nitrogen atoms in the organic carboxylic acid alcoholamine salt and / or alkyl alcoholamide molecules interact with the unoccupied iron orbitals to form a complex film that coats the surface of the iron-based amorphous powder particles. This complex film, acting as an anti-rust layer, prevents oxygen, water, and other molecules from coming into contact with the amorphous powder during the drying process and subsequent storage, thereby reducing oxygen growth.

[0059] The amorphous powder prepared by water atomization is taken out from the water and dried at 120° C. in an atmospheric atmosphere to obtain the desired amorphous powder.

[0060] That is to say, compared to the prior art in which amorphous powder is coated with an anti-rust layer through a special coating process after preparation, the preparation method provided in the embodiment of the present application can add an anti-rust layer to the amorphous powder during the water atomization powder making process, that is, there is no need for a special anti-rust coating process after powder making, so that the surface of the amorphous powder particles can have an anti-rust layer. The anti-rust layer can prevent oxygen, water and other molecules from contacting the amorphous powder during the drying process and the subsequent storage process, thereby reducing the oxygen increment. Therefore, the amorphous powder prepared in the embodiment of the present application can be dried in an atmospheric atmosphere after water atomization powder making, without the need for an inert gas atmosphere. However, the amorphous powder prepared by the prior art needs to be dried in an inert gas atmosphere or in a vacuum after the water atomization powder making is completed.

[0061] The amorphous powder prepared in the embodiment of the present application can be stored for a long time and maintain a low oxygen content without undergoing an anti-rust coating process after powder making.

[0062] The dried amorphous powder (without the anti-rust coating process after water atomization) can be placed in an environment A1 with a temperature of 20° C. to 45° C. and a humidity of 40% to 85%, and then the oxygen increment of the amorphous powder can be observed.

[0063] The oxygen increment after 7 days in environment A1 is less than 300 ppm. The oxygen increment after 7 days is specifically the difference between the oxygen content of the amorphous powder after 7 days in environment A1 and the oxygen content of the amorphous powder after drying.

[0064] The oxygen increment after 15 days in environment A1 is less than 500 ppm. The oxygen increment after 15 days is specifically the difference between the oxygen content of the amorphous powder after 15 days in environment A1 and the oxygen content of the amorphous powder after drying.

[0065] The amorphous powder prepared in the embodiment of the present application has good sphericity. Specifically, the laser particle size D50 of the amorphous powder prepared in the embodiment of the present application is 4-20 μm, and the sphericity is greater than 0.95.

[0066] The amorphous powder prepared in the embodiment of the present application has a relatively high crystallization enthalpy, which is 50-200 J / g.

[0067] Next, in specific embodiments, the amorphous powder preparation method and amorphous powder provided in this application are illustrated.

[0068] Example 1

[0069] This embodiment includes the following steps:

[0070] Step 101: Alloy smelting: The atomic percentages are: 12.0% B, 3.7% P, 0.6% Si, 1.5% C, 1.5% Cr, 0.3% Mn, and the remainder is Fe. The raw materials are prepared according to the alloy composition, using industrial pure iron, metallic silicon, industrial ferroboron, ferrophosphorus, carbon powder, metallic chromium, and electrolytic manganese. The alloy raw materials are melted and held at 1400°C for 30 minutes before pouring.

[0071] Step 102: water atomization powder making, adding a water-based rust inhibitor with a mass fraction of 1.0% to water, the steel flow rate during the atomization process is 10 kg / min, the water-liquid ratio is 15, and the atomization water pressure is 60 MPa;

[0072] Step 103: drying, drying the obtained powder in an air atmosphere at a temperature of 120° C. to obtain spherical amorphous powder;

[0073] Step 104: Testing: the powder D50 is 11.7 μm, the sphericity is 0.96, the crystallization enthalpy is 89 J / g, and the oxygen content is 751 ppm;

[0074] Step 105: The amorphous powder obtained in step 103 is stored in an environment with a temperature of 20° C. and a humidity of 40%. After 7 days, the oxygen increment is 35 ppm, and after 15 days, the oxygen increment is 59 ppm.

[0075] The appearance of the amorphous powder prepared in step 103 is as follows: Figure 1 As shown, the X-ray diffraction (XRD) results are as follows Figure 4 shown.

[0076] Example 2

[0077] This embodiment includes the following steps:

[0078] Step 201: Alloy smelting: The atomic percentages are: 10.2% B, 4.0% P, 5.0% Si, 1.6% C, 1.7% Cr, 0.1% Mn, and the remainder is Fe. The raw materials are prepared according to the alloy composition, using industrial pure iron, metallic silicon, industrial ferroboron, ferrophosphorus, carbon powder, metallic chromium, and electrolytic manganese. The alloy raw materials are melted and held at 1400°C for 30 minutes before pouring.

[0079] Step 202: water atomization powder making, adding a water-based rust inhibitor with a mass fraction of 2.0% to water, the steel flow rate during the atomization process is 10 kg / min, the water-liquid ratio is 15, and the atomization water pressure is 60 MPa;

[0080] Step 203: drying, drying the obtained powder in an air atmosphere at a temperature of 120° C. to obtain spherical amorphous powder;

[0081] Step 204: Powder testing: the powder D50 is 10.6 μm, the sphericity is 0.97, the crystallization enthalpy is 125 J / g, and the oxygen content is 628 ppm.

[0082] Step 205: The amorphous powder obtained in step 203 is stored in an environment with a temperature of 30° C. and a humidity of 65%. After 7 days, the oxygen increment is 134 ppm, and after 15 days, the oxygen increment is 347 ppm.

[0083] The appearance of the amorphous powder prepared in step 203 is as follows: Figure 2 As shown, the XRD results are Figure 4 shown.

[0084] Example 3

[0085] This embodiment includes the following steps:

[0086] Step 301: Alloy smelting: The atomic percentages are: 10.1% B, 3.7% P, 0.9% Si, 1.2% C, 1.3% Cr, 0.3% Mn, and the remainder is Fe. The raw materials are prepared according to the alloy composition, using industrial pure iron, metallic silicon, industrial ferroboron, ferrophosphorus, carbon powder, metallic chromium, and electrolytic manganese. The alloy raw materials are melted and held at 1400°C for 30 minutes before pouring.

[0087] Step 302: water atomization powder making, adding a water-based rust inhibitor with a mass fraction of 3.0% to water, the steel flow rate during the atomization process is 10 kg / min, the water-liquid ratio is 15, and the atomization water pressure is 60 MPa;

[0088] Step 303: drying, drying the obtained powder in an atmosphere at a temperature of 120° C. to obtain spherical amorphous powder;

[0089] Step 304: Testing shows that the powder D50 is 12.2 μm, the sphericity is 0.95, the crystallization enthalpy is 55 J / g, and the oxygen content is 434 ppm.

[0090] Step 305: The amorphous powder obtained in step 303 is stored in an environment with a temperature of 40° C. and a humidity of 65%. After 7 days, the oxygen increment is 158 ppm, and after 15 days, the oxygen increment is 384 ppm.

[0091] The appearance of the amorphous powder prepared in step 303 is as follows: Figure 3 As shown, the XRD results are Figure 4 shown.

[0092] Example 4

[0093] This embodiment includes the following steps:

[0094] Step 401: Alloy smelting: The atomic percentages are: 13.6% B, 3.6% P, 0.9% Si, 1.4% C, 1.0% Nb, 0.5% Mn, and the remainder is Fe. The raw materials are prepared according to the alloy composition, using industrial pure iron, metallic silicon, industrial ferroboron, ferrophosphorus, carbon powder, ferroniobium, and electrolytic manganese. The alloy raw materials are melted and held at 1400°C for 30 minutes before pouring.

[0095] Step 402: water atomization powder making, adding a water-based rust inhibitor with a mass fraction of 4.0% to water, the steel flow rate during the atomization process is 10 kg / min, the water-liquid ratio is 15, and the atomization water pressure is 60 MPa;

[0096] Step 403: drying, drying the obtained powder in an air atmosphere at a temperature of 120° C. to obtain spherical amorphous powder;

[0097] Step 404: Testing shows that the powder D50 is 14.5 μm, the sphericity is 0.95, the crystallization enthalpy is 55 J / g, and the oxygen content is 408 ppm.

[0098] Step 405: The amorphous powder obtained in step 403 is stored in an environment with a temperature of 45° C. and a humidity of 85%. After 7 days, the oxygen increment is 286 ppm, and after 15 days, the oxygen increment is 492 ppm.

[0099] The alloy compositions of Examples 1 to 4 are within the composition range shown in formula (1), and under given process conditions, spherical amorphous powders with smooth surfaces, few satellites, and oxygen content below 1000 ppm can be obtained.

[0100] Example 5

[0101] This embodiment includes the following steps:

[0102] Step 501: Alloy smelting: The atomic percentages are: 12.0% B, 3.7% P, 0.6% Si, 1.5% C, 1.5% Cr, 0.3% Mn, and the remainder is Fe. The raw materials are prepared according to the alloy composition, using industrial pure iron, metallic silicon, industrial ferroboron, ferrophosphorus, carbon powder, metallic chromium, and electrolytic manganese. The alloy raw materials are melted and held at 1400°C for 30 minutes before pouring.

[0103] Step 502: water atomization powder making, adding a water-based rust inhibitor with a mass fraction of 1.0% to water, the steel flow rate during the atomization process is 5 kg / min, the water-liquid ratio is 30, and the atomization water pressure is 60 MPa;

[0104] Step 503: drying, drying the obtained powder in an atmosphere at a temperature of 120° C. to obtain spherical amorphous powder;

[0105] Step 504: Testing shows that the powder D50 is 8.3 μm, the sphericity is 0.97, the crystallization enthalpy is 146 J / g, and the oxygen content is 860 ppm.

[0106] Example 6

[0107] This embodiment includes the following steps:

[0108] Step 601: Alloy smelting: The atomic percentages are: 12.0% B, 3.7% P, 0.6% Si, 1.5% C, 1.5% Cr, 0.3% Mn, and the remainder is Fe. The raw materials are prepared according to the alloy composition, using industrial pure iron, metallic silicon, industrial ferroboron, ferrophosphorus, carbon powder, metallic chromium, and electrolytic manganese. The alloy raw materials are melted and held at 1400°C for 30 minutes before pouring.

[0109] Step 602: water atomization powder making, adding a water-based rust inhibitor with a mass fraction of 3.0% to water, the steel flow rate during the atomization process is 3 kg / min, the water-liquid ratio is 60, and the atomization water pressure is 60 MPa;

[0110] Step 603: drying, drying the obtained powder in an atmosphere at a temperature of 120° C. to obtain spherical amorphous powder;

[0111] Step 604: Testing shows that the powder D50 is 4.2 μm, the sphericity is 0.98, the crystallization enthalpy is 168 J / g, and the oxygen content is 946 ppm.

[0112] In Examples 5 and 6, the atomized steel flow rate was reduced, the water-liquid ratio was increased, the powder particle size was reduced, and the sphericity was improved.

[0113] Example 7

[0114] This embodiment includes the following steps:

[0115] Step 701: Alloy smelting: The atomic percentages are: 10.2% B, 4.0% P, 5.0% Si, 1.6% C, 1.7% Cr, 0.1% Mn, and the remainder is Fe. The raw materials are prepared according to the alloy composition, using industrial pure iron, metallic silicon, industrial ferroboron, ferrophosphorus, carbon powder, metallic chromium, and electrolytic manganese. The alloy raw materials are melted and held at 1400°C for 30 minutes before pouring.

[0116] Step 702: water atomization powder making, adding a water-based rust inhibitor with a mass fraction of 2.0% to water, the steel flow rate during the atomization process is 10 kg / min, the water-liquid ratio is 15, and the atomization water pressure is 40 MPa;

[0117] Step 703: drying, drying the obtained powder in an air atmosphere at a temperature of 120° C. to obtain spherical amorphous powder;

[0118] Step 704 : Powder testing: the powder D50 is 16.2 μm, the sphericity is 0.98, the crystallization enthalpy is 109 J / g, and the oxygen content is 291 ppm.

[0119] Example 8

[0120] This embodiment includes the following steps:

[0121] Step 801: Alloy smelting: The atomic percentages are: 10.2% B, 4.0% P, 5.0% Si, 1.6% C, 1.7% Cr, 0.1% Mn, and the remainder is Fe. The raw materials are prepared according to the alloy composition, using industrial pure iron, metallic silicon, industrial ferroboron, ferrophosphorus, carbon powder, metallic chromium, and electrolytic manganese. The alloy raw materials are melted and held at 1400°C for 30 minutes before pouring.

[0122] Step 802: water atomization powder making, adding a water-based rust inhibitor with a mass fraction of 2.0% to water, the steel flow rate during the atomization process is 10 kg / min, the water-liquid ratio is 15, and the atomization water pressure is 80 MPa;

[0123] Step 803: drying, drying the obtained powder in an atmosphere at a temperature of 120° C. to obtain spherical amorphous powder;

[0124] Step 804: Powder testing: the powder D50 is 8.9 μm, the sphericity is 0.95, the crystallization enthalpy is 128 J / g, and the oxygen content is 434 ppm.

[0125] In Examples 7 and 8, the atomizing water pressure was changed, and spherical amorphous powders were obtained in the range of 40-80 MPa.

[0126] Comparative Example 1

[0127] This comparative example comprises the following steps:

[0128] Step 111: Alloy smelting: The atomic percentages are: 9.7% B, 3.8% P, 0.6% Si, 0.8% C, 1.7% Cr, 0.1% Mn, and the remainder is Fe. The raw materials are prepared according to the alloy composition, using industrial pure iron, metallic silicon, industrial ferroboron, ferrophosphorus, carbon powder, metallic chromium, and electrolytic manganese. The alloy raw materials are melted and held at 1400°C for 30 minutes before pouring.

[0129] Step 112: water atomization powder making, adding a water-based rust inhibitor with a mass fraction of 1.0% to water, the steel flow rate during the atomization process is 10 kg / min, the water-liquid ratio is 15, and the atomization water pressure is 60 MPa;

[0130] Step 113: drying, drying the obtained powder in an atmosphere at a temperature of 120° C. to obtain a spherical powder;

[0131] Step 114: Powder testing: the powder D50 is 12.4 μm, the sphericity is 0.95, the powder is partially crystallized, the crystallization enthalpy is 32 J / g, and the oxygen content is 980 ppm.

[0132] Among them, the XRD results of the amorphous powder prepared in step 113 are as follows: Figure 5 shown.

[0133] Among them, the Fe content in the alloy of Comparative Example 1 exceeds the range given by formula (1), the amorphous forming ability is poor, and amorphous powder cannot be prepared.

[0134] Comparative Example 2

[0135] This comparative example comprises the following steps:

[0136] Step 211: Alloy smelting: The atomic percentages are: 9.8% B, 0.8% P, 7.7% Si, 2.0% C, 1.9% Cr, 0.1% Mn, and the remainder is Fe. The raw materials are prepared according to the alloy composition, using industrial pure iron, metallic silicon, industrial ferroboron, ferrophosphorus, carbon powder, metallic chromium, and electrolytic manganese. The alloy raw materials are melted and held at 1400°C for 30 minutes before pouring.

[0137] Step 212: water atomization powder making, adding a water-based rust inhibitor with a mass fraction of 1.0% to water, the steel flow rate during the atomization process is 10 kg / min, the water-liquid ratio is 15, and the atomization water pressure is 60 MPa;

[0138] Step 213: drying, drying the obtained powder in an atmosphere at a temperature of 120° C. to obtain an irregularly shaped powder;

[0139] Step 214: Powder testing: the powder D50 is 13.6 μm, the sphericity is 0.72, the crystallization enthalpy is 25 J / g, and the oxygen content is 745 ppm.

[0140] Among them, the XRD results of the amorphous powder prepared in step 213 are as follows: Figure 5 shown.

[0141] The P content of Comparative Example 2 is lower than the range given by formula (1), the amorphous forming ability is poor, and amorphous powder cannot be prepared. In addition, the fluidity of the molten steel is poor and the sphericity of the powder is low.

[0142] Comparative Example 3

[0143] This comparative example comprises the following steps:

[0144] Step 311: Alloy smelting: The atomic percentages are: 12.0% B, 3.7% P, 0.6% Si, 1.5% C, 1.5% Cr, 0.3% Mn, and the remainder is Fe. The raw materials are prepared according to the alloy composition, using industrial pure iron, metallic silicon, industrial ferroboron, ferrophosphorus, carbon powder, metallic chromium, and electrolytic manganese. The alloy raw materials are melted and held at 1400°C for 30 minutes before pouring.

[0145] Step 312: water atomization powder making, adding a water-based rust inhibitor with a mass fraction of 1.0% to water, the steel flow rate during the atomization process is 20 kg / min, the water-liquid ratio is 7.5, and the atomization water pressure is 60 MPa;

[0146] Step 313: drying the obtained powder in an air atmosphere at a temperature of 120° C. to obtain spherical alloy powder;

[0147] Step 314: Powder testing: the powder D50 is 14.8 μm, the sphericity is 0.96, the crystallization enthalpy is 26 J / g, and the oxygen content is 628 pm.

[0148] Comparative Example 4

[0149] This comparative example comprises the following steps:

[0150] Step 411: Alloy smelting: The atomic percentages are: 10.2% B, 4.0% P, 5.0% Si, 1.6% C, 1.7% Cr, 0.1% Mn, and the remainder is Fe. The raw materials are prepared according to the alloy composition, using industrial pure iron, metallic silicon, industrial ferroboron, ferrophosphorus, carbon powder, metallic chromium, and electrolytic manganese. The alloy raw materials are melted and held at 1400°C for 30 minutes before pouring.

[0151] Step 412: water atomization powder making, adding a water-based rust inhibitor with a mass fraction of 2.0% to water, the steel flow rate during the atomization process is 20 kg / min, the water-liquid ratio is 7.5, and the atomization water pressure is 60 MPa;

[0152] Step 413: Drying: Drying the obtained powder in an atmosphere at a temperature of 120° C. to obtain spherical alloy powder;

[0153] Step 414: Powder testing: the powder D50 is 16.4 μm, the sphericity is 0.97, the crystallization enthalpy is 29 J / g, and the oxygen content is 492 pm.

[0154] The atomized steel flow rate of Comparative Examples 3 and 4 is 20 kg / min, the water-liquid ratio is less than 12, and the cooling capacity is poor. Figure 6 As shown, a crystal peak appears on the XRD spectrum, indicating that the schemes of Comparative Examples 3-5 cannot prepare amorphous powder.

[0155] Comparative Example 5

[0156] This comparative example comprises the following steps:

[0157] Step 511: Alloy smelting: The atomic percentages are: 12.0% B, 3.7% P, 0.6% Si, 1.5% C, 1.5% Cr, 0.3% Mn, and the remainder is Fe. The raw materials are prepared according to the alloy composition, using industrial pure iron, metallic silicon, industrial ferroboron, ferrophosphorus, carbon powder, metallic chromium, and electrolytic manganese. The alloy raw materials are melted and held at 1400°C for 30 minutes before pouring.

[0158] Step 512: water atomization powder production, no rust inhibitor is added to the atomized water, the steel flow rate during the atomization process is 10 kg / min, the water-to-liquid ratio is 15, and the atomization water pressure is 90 MPa;

[0159] Step 513: Drying: Drying the obtained powder in a nitrogen atmosphere at a temperature of 120° C. to obtain spherical alloy powder;

[0160] Step 514: Powder testing: powder D50 is 9.8 μm, sphericity is 0.71, crystallization enthalpy is 96 J / g, and oxygen content is 962 pm;

[0161] Step 515: The amorphous powder obtained in step 513 is stored in an environment with a temperature of 20° C. and a humidity of 40%. After 7 days, the oxygen increment is 315 ppm, and after 15 days, the oxygen increment is 507 ppm.

[0162] The appearance of the amorphous powder prepared in step 513 is as follows: Figure 7 shown.

[0163] Comparative Example 6

[0164] This comparative example comprises the following steps:

[0165] Step 611: Alloy smelting: The atomic percentages are: 10.2% B, 4.0% P, 5.0% Si, 1.6% C, 1.7% Cr, 0.1% Mn, and the remainder is Fe. The raw materials are prepared according to the alloy composition, using industrial pure iron, metallic silicon, industrial ferroboron, ferrophosphorus, carbon powder, metallic chromium, and electrolytic manganese. The alloy raw materials are melted and held at 1400°C for 30 minutes before pouring.

[0166] Step 612: Powdering by water atomization, without adding rust inhibitor to the atomized water, with a steel flow rate of 20 kg / min, a water-to-liquid ratio of 7.5, and an atomizing water pressure of 100 MPa during the atomization process;

[0167] Step 613: Drying: Drying the obtained powder in an air atmosphere at a temperature of 120° C. to obtain spherical alloy powder;

[0168] Step 614: Powder testing: powder D50 is 7.4 μm, sphericity is 0.59, crystallization enthalpy is 108 J / g, and oxygen content is 2996 pm;

[0169] Step 615: The amorphous powder obtained in step 613 is stored in an environment with a temperature of 30° C. and a humidity of 65%. After 7 days, the oxygen increment is 1045 ppm, and after 15 days, the oxygen increment is 1944 ppm.

[0170] In Comparative Examples 5 and 6, the atomizing water pressure is greater than 80 MPa, the water flow rate increases, the atomization area is more concentrated, the atomization area decreases, an atomization dead zone appears at the edge of the molten steel, and the sphericity of the obtained amorphous powder is poor.

[0171] The appearance of the amorphous powder prepared in step 613 is as follows: Figure 8 shown.

[0172] Comparative Example 7

[0173] This comparative example comprises the following steps:

[0174] Step 711: Alloy smelting: The atomic percentages are: 12.0% B, 3.7% P, 0.6% Si, 1.5% C, 1.5% Cr, 0.3% Mn, and the remainder is Fe. The raw materials are prepared according to the alloy composition, using industrial pure iron, metallic silicon, industrial ferroboron, ferrophosphorus, carbon powder, metallic chromium, and electrolytic manganese. The alloy raw materials are melted and held at 1400°C for 30 minutes before pouring.

[0175] Step 712: water atomization powder production, without adding rust inhibitor to the atomized water, the steel flow rate during the atomization process is 10 kg / min, the water-to-liquid ratio is 15, and the atomization water pressure is 60 MPa;

[0176] Step 713: Drying: Drying the obtained powder in a nitrogen atmosphere at a temperature of 120° C. to obtain spherical amorphous powder;

[0177] Step 714: Testing shows that the powder D50 is 11.9 μm, the sphericity is 0.96, the crystallization enthalpy is 82 J / g, and the oxygen content is 912 ppm.

[0178] Step 715: The amorphous powder obtained in step 713 is stored in an environment with a temperature of 40° C. and a humidity of 65%. After 7 days, the oxygen increment is 2502 ppm, and after 15 days, the oxygen increment is 3652 ppm.

[0179] The appearance of the amorphous powder prepared in step 713 is as follows: Figure 9 shown.

[0180] Comparative Example 8

[0181] This comparative example comprises the following steps:

[0182] Step 811: Alloy smelting: The atomic percentages are: 12.0% B, 3.7% P, 0.6% Si, 1.5% C, 1.5% Cr, 0.3% Mn, and the remainder is Fe. The raw materials are prepared according to the alloy composition, using industrial pure iron, metallic silicon, industrial ferroboron, ferrophosphorus, carbon powder, metallic chromium, and electrolytic manganese. The alloy raw materials are melted and held at 1400°C for 30 minutes before pouring.

[0183] Step 812: water atomization powder production, no rust inhibitor is added to the atomized water, the steel flow rate during the atomization process is 10 kg / min, the water-to-liquid ratio is 15, and the atomization water pressure is 60 MPa;

[0184] Step 813: Drying: Drying the obtained powder in an air atmosphere at a temperature of 120° C. to obtain spherical amorphous powder;

[0185] Step 814: Powder testing: the powder D50 is 11.6 μm, the sphericity is 0.95, the crystallization enthalpy is 88 J / g, and the oxygen content is 3090 ppm.

[0186] Step 815: The amorphous powder obtained in step 813 is stored in an environment with a temperature of 45° C. and a humidity of 85%. After 7 days, the oxygen increment is 3649 ppm, and after 15 days, the oxygen increment is 4554 ppm.

[0187] The appearance of the amorphous powder prepared in step 813 is as follows: Figure 10 shown.

[0188] The preparation parameters and performance parameters of the above embodiments and comparative examples are shown in Table 1.

[0189] Table 1

[0190]

[0191]

[0192] The storage environment parameters and oxygen increments of the amorphous powders prepared in Examples 1-4 and Comparative Examples 5-8 are shown in Table 2.

[0193] Table 2

[0194]

[0195] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent replacements, improvements, etc. made on the basis of the technical solution of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing amorphous powder, characterized in that: The steps include: a) preparing the ingredients according to the atomic percentage of the elements shown in formula (1), and then smelting to obtain a molten alloy; b) using atomized water containing a first rust inhibitor to atomize the alloy liquid to obtain the amorphous powder; wherein the mass fraction of the first rust inhibitor in the atomized water is 0.5% to 4%; c), drying the amorphous powder; in, Fe 100-a-b-c-d-e-f-g B a P b Si c C d Cr e Mn f Nb g (1) in, a=12%, b=3.7%, c=0.6%, d=1.5%, e=1.5%, f=0.3%, g=0; Alternatively, a=10.2%, b=4.0%, c=5%, d=1.6%, e=1.7%, f=0.1%, g=0; Alternatively, a=10.1%, b=3.7%, c=0.9%, d=1.2%, e=1.3%, f=0.3%, g=0; Alternatively, a=13.6%, b=3.6%, c=0.9%, d=1.4%, e=0%, f=0.5%, g=1%; Alternatively, a=12.0%, b=3.7%, c=0.6%, d=1.5%, e=1.5%, f=0.3%, g=0; Wherein, the first rust inhibitor is a long carbon chain carboxylic acid ester and / or triethanolamine borate; During the water atomization powder making process, the ratio of the flow rate of the atomized water to the alloy liquid is 12-60, and the atomized water pressure is 40-80 MPa.

2. The method according to claim 1, characterized in that Before the alloy liquid is subjected to the water atomization powder making process, the alloy liquid is heated to 250-350° C. above the melting point and kept warm for 20-40 minutes; during the water atomization powder making process, the flow rate of the alloy liquid is 3-15 kg / min.

3. The method according to claim 1, characterized in that The amorphous powder was dried at 120° C. in air atmosphere.

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