METHOD FOR PREPARING POWDER MATERIAL AND APPLICATION THEREOF

Abstract

The present disclosure provides a method for preparing a powder material and an application thereof. The preparation method includes: obtaining an initial alloy ribbon including a matrix phase and a dispersed particle phase by solidifying an alloy melt, and then removing the matrix phase in the initial alloy ribbon while retaining the dispersed particle phase, so as to obtain a powder material composed of original dispersed particle phase. The preparation method of the present disclosure is simple in process and can prepare multiple powder materials of nano-level, sub-micron-level and micro-level. The powder materials have good application prospects in the fields such as catalytic materials, powder metallurgy, composite materials, wave-absorbing materials, sterilization materials, metal injection molding, 3D printing and coating.

Claims

1. A method for preparing a powder material, comprising the following steps: at step 1: selecting initial alloy raw materials, and melting the initial alloy raw materials according to a ratio of initial alloy ingredients to obtain a homogeneous initial alloy melt containing an impurity element T, wherein T comprises at least one of O, H, N, P, S, F, Cl, I, and Br, and an average ingredient of the initial alloy melt is A.sub.aM.sub.bT.sub.d; wherein, when M comprises B, A comprises at least one of Sn, Ge, Cu and Zn; when M comprises Bi, A comprises at least one of Sn, Ga and Al; when M comprises at least one of Si and Ge, A comprises at least one of Zn, Sn, Pb, Ga, In, Ag, Bi and Al; a, b and d represents atomic percent contents of corresponding constituent elements, and 60%≤a<99.5%, 0.5%≤b<40% and 0<d≤10%; at step 2: solidifying the initial alloy melt into an initial alloy ribbon; wherein a solidification structure of the initial alloy ribbon comprises a matrix phase and a dispersed particle phase; the matrix phase has a lower melting point than the dispersed particle phase, the dispersed particle phase is wrapped in the matrix phase; during the solidification of the initial alloy melt, the impurity element T in the initial alloy melt is redistributed in the dispersed particle phase and the matrix phase, and is enriched in the matrix phase, so as to purify the dispersed particle phase; wherein a major ingredient of the dispersed particle phase in the initial alloy ribbon is M.sub.x1T.sub.z1, an average ingredient of the matrix phase is mainly A.sub.x2T.sub.z2; and 98.5%≤x1≤100%, 0≤z1≤1.5%;80%≤x2<100%, 0<z2≤20%; z1<d<z2; x1, z1, x2, and z2 represent atomic percent contents of the corresponding constituent elements respectively; at step 3: removing the matrix phase in the initial alloy ribbon, and retaining the dispersed particle phase which is not removed at the same time during the removal of the matrix phase; collecting the separated dispersed particle phase, so as to obtain a target high-purity powder material composed of original dispersed particles.

2-5. (canceled)

6. The method of claim 1, wherein a method for removing the matrix phase in the alloy ribbon comprises at least one of acid reaction removal, alkali reaction removal, vacuum volatilization removal, and matrix phase natural oxidation-powdering peeling removal.

7. The method of claim 1, wherein the target powder material has a particle size of 2 nm to 3 mm.

8-9. (canceled)

10. An alloy ribbon, comprising an endogenous powder and a wrapping body; a solidification structure of the alloy ribbon comprises a matrix phase and a dispersed particle phase, the matrix phase is the wrapping body, and the dispersed particle phase is the endogenous powder; the wrapping body has a lower melting point than the endogenous powder, and the endogenous powder is wrapped in the wrapping body; a major ingredient of the endogenous powder in the alloy ribbon is M.sub.x1T.sub.z1, an average ingredient of the wrapping body is mainly A.sub.x2T.sub.z2; and 98.5%≤x1≤100%, 0≤z1≤1.5%; 80%≤x2<100%, 0<z2≤20%; z1<z2; x1, z1, x2,and z2 represent atomic percent contents of the corresponding constituent elements respectively; wherein when M comprises B, A comprises at least one of Sn, Ge, Cu and Zn; when M comprises Bi, A comprises at least one of Sn, Ga and Al; when M comprises at least one of Si and Ge, A comprises at least one of Zn, Sn, Pb, Ga, In, Ag, Bi and Al; and T comprises at least one of O, H, N, P, S, F, Cl, I, and Br.

11. A method for preparing a powder material, comprising the following steps: providing an initial alloy, wherein an ingredient of the initial alloy is A.sub.aM.sub.b, a microstructure of the initial alloy is composed of a matrix phase with an ingredient A and a dispersed particle phase with an ingredient M; A is selected from at least one of Sn, Pb, Ga, In, Al, La, Ge, Cu, K, Na, and Li; M is selected from at least one of B, Bi, Fe, Ni, Cu, and Ag; a and b represent atomic percent contents of the corresponding constituent elements respectively, and 1%≤b≤40%, a+b=100%; mixing the initial alloy with a corrosive solution, so that the matrix phase reacts with the corrosive solution to change into ions and enter the solution, and the dispersed particle phase is separated out so as to obtain a powder material with the ingredient M.

12-19. (canceled)

20. The method of claim 11, wherein the powder material has a particle size of 2 nm to 500 μm.

21. A method for preparing a powder material, comprising the following steps: selecting an initial alloy with an ingredient A.sub.aM.sub.b, wherein a and b represents atomic percent contents of corresponding constituent elements, and 0.1%≤b≤40%, a+b=100%; when M is at least one of Si and Ge, A comprises at least one of Zn, Sn, Pb, Ga, In, Ag, Bi, and Al; when M is at least one of B, Cr, and V, A is Zn; when M is at least one of Fe and Mn, A is Mg; when M is C, A comprises at least one of Mg and Zn; fully melting the initial alloy to obtain an initial alloy melt, wherein during subsequent cooling and solidification processes, no intermetallic compound is formed between A and M, but separation of A and M occurs, so that a solidified state alloy in which a dispersed particle phase with an ingredient M is distributed in a matrix phase A is obtained; removing the matrix phase A in the solidified state alloy, so that the dispersed particle phase which is not removed at the same time is retained and separated out in a dispersed manner so as to obtain a powder material with the ingredient M.

22. The method of claim 21, wherein the matrix phase A is removed by one of acid reaction removal, alkali reaction removal, and vacuum volatilization removal.

23-29. (canceled)

30. An application of the powder material prepared by the method of claim 1 in catalytic materials.

31. An application of the powder material prepared by the method of claim 1 in powder metallurgy.

32. An application of the powder material prepared by the method of claim 1 in composite materials.

33. An application of the powder material prepared by the method of claim 1 in coatings.

34. The alloy ribbon of claim 10, wherein the alloy ribbon has a thickness of 5 μm to 10 mm, and a width of a cross section of the alloy ribbon is two or more times the thickness.

35. The alloy ribbon of claim 10, wherein the endogenous powder has a particle size of 2 nm to 99 μm.

36. The alloy ribbon of claim 10, wherein the endogenous powder has a particle size of 2 nm to 1 μm.

Description

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0143] A method for preparing the powder material will be further described below in combination with the following specific embodiments.

Embodiment 1

[0144] This embodiment provides a method for preparing a nano-level B powder, which includes the following steps.

[0145] An alloy with a formulation molecular formula Cu.sub.80B.sub.20 was selected. Raw materials were weighed according to the formula, and subjected to vacuum induction melting to obtain an alloy melt with an ingredient Cu.sub.80B.sub.20. The alloy melt was prepared into Cu.sub.80B.sub.20 thin ribbon-like initial alloy fragments with a thickness of ˜15 μm at a rate of ˜10.sup.6K/s by using copper roller spinning and rapid-solidification method. The microstructure of the fragments included a matrix phase composed of Cu and a dispersed particle phase composed of nano-level B particles. The dispersed particle phase had a particle size of 2 nm to 100 nm.

[0146] At room temperature, 0.25 g of the Cu.sub.80B.sub.20 initial alloy fragments prepared as above was immersed in 50 ml of an aqueous hydrochloric acid solution with a concentration of 2 mol/L and a temperature of 60° C. for reaction. During the reaction, the matrix phase composed of Cu reacted with the hot hydrochloric acid and entered the solution, whereas the nano-level B particles which did not react with the aqueous hydrochloric acid solution were gradually separated out in a dispersed manner. After 25 minutes, the obtained nano-level B particles were separated from the solution, cleaned and dried to obtain a nano-level B particle powder, with a particle size of 2 nm to 100 nm.

Embodiment 2

[0147] This embodiment provides a method for preparing a sub-micron-level B powder, which includes the following steps.

[0148] An alloy with a formulation molecular formula Sn.sub.98B.sub.2 was selected. Raw materials were weighed according to the formula, and subjected to vacuum induction melting to obtain an alloy melt with an ingredient Sn.sub.98B.sub.2. The alloy melt was prepared into Sn.sub.98B.sub.2 thin ribbon-like initial alloy fragments with a thickness of 150 μm at a rate of 10.sup.3K/s to 10.sup.4K/s by using copper roller spinning and rapid-solidification method. The microstructure of the fragments included a matrix phase composed of Sn and a dispersed particle phase composed of sub-micron-level B particles. The dispersed particle phase had a particle size of 100 nm to 2 μm.

[0149] At room temperature, 0.25 g of the Sn.sub.98B.sub.2 initial alloy fragments prepared as above was immersed in 50 ml of an aqueous sulfuric acid solution with a concentration of 0.5 mol/L for reaction. During the reaction, the matrix phase composed of the active element Sn reacted with an acid and entered the solution, whereas the sub-micron-level B particles which did not react with the acid were gradually separated out in a dispersed manner. After 20 minutes, the obtained sub-micron-level B particles were separated from the solution, cleaned and dried to obtain a sub-micron-level B particle powder, with a particle size of 100 nm to 2 μm.

Embodiment 3

[0150] This embodiment provides a method for preparing a nano-level Bi powder, which includes the following steps.

[0151] An alloy with a formulation molecular formula Al.sub.75B.sub.i25 was selected. Raw materials were weighed according to the formula, and subjected to vacuum induction melting to obtain an alloy melt with an ingredient Al.sub.75B.sub.i25. The alloy melt was prepared into Al.sub.75B.sub.i25thin alloy ribbon with a thickness of ˜20 μm at a rate of ˜10.sup.6K/s. The microstructure of the thin alloy ribbon included a matrix phase composed of Al and a dispersed particle phase composed of nano-level Bi particles. The dispersed particle phase had a particle size of 2 nm to 150 nm.

[0152] At room temperature, 0.5 g of the Al.sub.75B.sub.i25 initial alloy fragments prepared as above was immersed in 50 ml of an aqueous hydrochloric acid solution with a concentration of 1 mol/L for reaction. During the reaction, the matrix phase composed of the active element Al reacted with an acid and entered the solution, whereas the nano-level Bi particles which did not react with the acid were gradually separated out in a dispersed manner. After 20 minutes, the obtained nano-level Bi particles were separated from the solution, cleaned and dried to obtain a nano-level Bi particle powder, with a particle size of 2 nm to 150 nm.

Embodiment 4

[0153] This embodiment provides a method for preparing a sub-micron-level Fe powder, which includes the following steps.

[0154] An alloy with a formulation molecular formula La.sub.75Fe.sub.25 was selected. Raw materials were weighed according to the formula, and subjected to vacuum induction melting to obtain an alloy melt with an ingredient La.sub.75Fe.sub.25. The alloy melt was prepared into La.sub.75Fe.sub.25 thin ribbon-like initial alloy fragments with a thickness of 150 μm at a rate of 10.sup.3K/s to 10.sup.4K/s by using copper roller spinning and rapid-solidification method. The microstructure of the initial alloy fragments included a matrix phase composed of La and a dispersed particle phase composed of sub-micron-level Fe particles. The dispersed particle phase had a particle size of 200 nm to 3 μm.

[0155] At room temperature, 0.5 g of the La.sub.75Fe.sub.25 initial alloy fragments prepared as above was immersed in 50 ml of an aqueous hydrochloric acid solution with a concentration of 0.01 mol/L for reaction. During the reaction, the matrix phase composed of the active element La reacted with an acid and entered the solution, whereas the dispersed Fe particles having slightly lower activity were gradually separated out. During the reaction, an auxiliary magnetic field was applied to ensure the newly-separated Fe particles can be separated from the acid solution in time. After 30 minutes, the sub-micron-level Fe particles were gradually collected, cleaned and dried to obtain a sub-micron-level Fe particle powder, with a particle size of 200 nm to 3 μm.

Embodiment 5

[0156] This embodiment provides a method for preparing a sub-micron-level Fe powder, which includes the following steps.

[0157] An alloy with a formulation molecular formula Li.sub.75Fe.sub.25 was selected. Raw materials were weighed according to the formula, and subjected to vacuum induction melting to obtain an alloy melt with an ingredient Li.sub.75Fe.sub.25. The alloy melt was prepared into Li.sub.75Fe.sub.25 thin ribbon-like initial alloy fragments with a thickness of 150 μm at a rate of 10.sup.3K/s to 10.sup.4K/s by using copper roller spinning and rapid-solidification method. The microstructure of the initial alloy fragments included a matrix phase composed of Li and a dispersed particle phase composed of sub-micron-level Fe particles. The dispersed particle phase had a particle size of 200 nm to 3 μm.

[0158] At room temperature, 0.5 g of the Li.sub.75Fe.sub.25 initial alloy fragments prepared as above was immersed in 50 ml of an aqueous solution for reaction. During the reaction, the matrix phase composed of the active element Li reacted with water and entered the solution, whereas the dispersed Fe particles were separated out. After 5 minutes, the sub-micron-level Fe particles were collected gradually, cleaned and dried to obtain a sub-micron-level Fe particle powder, with a particle size of 200 nm to 3 μm.

Embodiment 6

[0159] This embodiment provides a method for preparing a nano-level Fe powder, which includes the following steps.

[0160] An alloy with a formulation molecular formula Li.sub.75Fe.sub.25 was selected. Raw materials were weighed according to the formula, and subjected to vacuum induction melting to obtain an alloy melt with an ingredient Li.sub.75Fe.sub.25. The alloy melt was prepared into Li.sub.75Fe.sub.25 thin ribbon-like initial alloy fragments with a thickness of ˜15 μm at a rate of ˜10.sup.6K/s by using copper roller spinning and rapid-solidification method. The microstructure of the initial alloy fragments included a matrix phase composed of Li and a dispersed particle phase composed of nano-level Fe particles. The dispersed particle phase had a particle size of 2 nm to 200 nm.

[0161] At room temperature, 0.25 g of the Li.sub.75Fe.sub.25 initial alloy fragments prepared as above was immersed in 50 ml of an aqueous solution deoxygenated by argon gas for reaction. During the reaction, the matrix phase composed of the active element Li reacted with water and entered the solution, whereas the dispersed nano-level Fe particles were separated out. After 5 minutes, the obtained nano-level Fe particles were separated from the solution, so as to obtain a nano-level Fe particle powder with a particle size of 2 nm to 200 nm.

Embodiment 7

[0162] This embodiment provides a method for preparing a nano-level Ni powder, which includes the following steps.

[0163] An alloy with a formulation molecular formula Li.sub.80Ni.sub.20 was selected. Raw materials were weighed according to the formula, and subjected to vacuum induction melting to obtain an alloy melt with an ingredient Li.sub.80Ni.sub.20. The alloy melt was prepared into Li.sub.80Ni.sub.20 thin ribbon-like initial alloy fragments with a thickness of ˜15 μm at a rate of ˜10.sup.6K/s by using copper roller spinning and rapid-solidification method. The microstructure of the initial alloy fragments included a matrix phase composed of Li and a dispersed particle phase composed of nano-level Ni particles. The dispersed particle phase had a particle size of 2 nm to 200 nm.

[0164] At room temperature, 0.25 g of the Li.sub.80Ni.sub.20 initial alloy fragments prepared as above was immersed in 50 ml of an aqueous solution deoxygenated by argon gas for reaction. During the reaction, the matrix phase composed of the active element Li reacted with water and entered the solution, whereas the dispersed nano-level Ni particles were separated out. After 5 minutes, the obtained nano-level Ni particles were separated from the solution, so as to obtain a nano-level Ni particle powder with a particle size of 2 nm to 200 nm.

Embodiment 8

[0165] This embodiment provides a method for preparing a nano-level Ag powder, which includes the following steps.

[0166] An alloy with a formulation molecular formula Pb.sub.75Ag.sub.25 was selected. Raw materials were weighed according to the formula, and subjected to vacuum induction melting to obtain an alloy melt with an ingredient Pb.sub.75Ag.sub.25. The alloy melt was prepared into Pb.sub.75Ag.sub.25 thin ribbon-like initial alloy fragments with a thickness of ˜20 μm at a rate of ˜10.sup.6K/s by using copper roller spinning and rapid-solidification method. The microstructure of the initial alloy fragments included a matrix phase composed of Pb and a dispersed particle phase composed of nano-level Ag particles. The dispersed particle phase had a particle size of 2 nm to 200 nm.

[0167] At room temperature, 0.5 g of the Pb.sub.75Ag.sub.25 initial alloy fragments prepared as above was immersed in 50 ml of an aqueous hydrochloric acid solution with a concentration of 2 mol/L for reaction. During the reaction, the matrix phase composed of the active element Pb reacted with an acid and entered the solution, whereas the nano-level Ag particles which did not react with the acid were gradually separated out in a dispersed manner. After 10 minutes, the obtained sub-spheroidal nano-level Ag particles were separated from the solution and then cleaned and dried so as to obtain a nano-level Ag particle powder with a particle size of 2 nm to 200 nm.

Embodiment 9

[0168] This embodiment provides a method for preparing a micron-level Ag powder, which includes the following steps.

[0169] An alloy with a formulation molecular formula Pb.sub.75Ag.sub.25 was selected. Raw materials were weighed according to the formula, and subjected to vacuum induction melting to obtain an alloy melt with an ingredient Pb.sub.75Ag.sub.25. The alloy melt was prepared into Pb.sub.75Ag.sub.25 sheets with a thickness of ˜2 mm at a rate of ˜500K/s by casting. The microstructure of the sheets included a matrix phase composed of Pb and a dispersed particle phase composed of micron-level Ag dendritic particles. The dispersed particle phase had a particle size of 0.5 μm to 30 μm.

[0170] At room temperature, 0.5 g of the Pb.sub.75Ag.sub.25 initial alloy fragments prepared as above was immersed in 50 ml of an aqueous hydrochloric acid solution with a concentration of 3 mol/L for reaction. During the reaction, the matrix phase composed of the active element Pb reacted with an acid and entered the solution, whereas the micron-level Ag particles which did not react with the acid were gradually separated out in a dispersed manner. After 20 minutes, the obtained micron-level Ag dendritic particles were separated from the solution and then cleaned and dried so as to obtain a micron-level Ag particle powder with a particle size of 0.5 μm to 30 μm.

Embodiment 10

[0171] This embodiment provides a method for preparing a nano-level Ag powder, which includes the following steps.

[0172] An alloy with a formulation molecular formula K.sub.75Ag.sub.25 was selected. Raw materials were weighed according to the formula, and subjected to vacuum induction melting to obtain an alloy melt with an ingredient K.sub.75Ag.sub.25. The alloy melt was prepared into K.sub.75Ag.sub.25thin ribbon-like initial alloy fragments with a thickness of ˜20 μm at a rate of ˜10.sup.6K/s by using copper roller spinning and rapid-solidification method. The microstructure of the initial alloy fragments included a matrix phase composed of K and a dispersed particle phase composed of nano-level Ag particles. The dispersed particle phase had a particle size of 2 nm to 200 nm.

[0173] At room temperature, 0.5 g of the K.sub.75Ag.sub.25 initial alloy fragments prepared as above was immersed in 50 ml of an aqueous solution for reaction. During the reaction, the matrix phase composed of K reacted with water and entered the solution, whereas the nano-level Ag particles which did not react with water were gradually separated out in dispersed manner. After 5 minutes, the obtained nano-level Ag particles were separated from the solution and then cleaned and dried so as to obtain a nano-level Ag particle powder with a particle size of 2 nm to 200 nm.

Embodiment 11

[0174] This embodiment provides a method for preparing a sub-micron-level Ag powder, which includes the following steps.

[0175] An alloy with a formulation molecular formula Na.sub.75Ag.sub.25 was selected. Raw materials were weighed according to the formula, and subjected to vacuum induction melting to obtain an alloy melt with an ingredient Na.sub.75Ag.sub.25. The alloy melt was prepared into Na.sub.75Ag.sub.25thin ribbon-like initial alloy fragments with a thickness of ˜150 μm at a rate of 10.sup.3K/s to 10.sup.4K/s by using copper roller spinning and rapid-solidification method. The microstructure of the initial alloy fragments included a matrix phase composed of Na and a dispersed particle phase composed of sub-micron-level Ag particles. The dispersed particle phase had a particle size of 100 nm to 3 μm.

[0176] At room temperature, 0.5 g of the Na.sub.75Ag.sub.25 initial alloy fragments prepared as above was immersed in 50 ml of an aqueous solution for reaction. During the reaction, the matrix phase composed of Na reacted with water and entered the solution, whereas the sub-micron-level Ag particles which did not react with water were gradually separated out in dispersed manner. After 5 minutes, the obtained sub-micron-level Ag particles were separated from the solution and then cleaned and dried so as to obtain a sub-micron-level Ag particle powder with a particle size of 100 nm to 3 μm.

Embodiment 12

[0177] This embodiment provides a method for preparing a micron-level Cu powder, which includes the following steps.

[0178] An alloy with a formulation molecular formula Pb.sub.80Cu.sub.20 was selected. Raw materials were weighed according to the formula, and subjected to vacuum induction melting to obtain an alloy melt with an ingredient Pb.sub.80Cu.sub.20. The alloy melt was prepared into Pb.sub.80Cu.sub.20 sheets with a thickness of 3 mm at a rate of ˜200K/s. The microstructure of the sheets included a matrix phase composed of Pb and a dispersed particle phase composed of micron-level Cu particles. The dispersed particle phase had a particle size of 1 μm to 50 μm.

[0179] At room temperature, 0.5 g of the Pb.sub.80Cu.sub.20initial alloy prepared as above was immersed in 100 ml of an aqueous hydrochloric acid solution with a concentration of 2 mol/L for reaction. During the reaction, the matrix phase composed of the active element Pb reacted with an acid and entered the solution, whereas the micron-level Cu particles difficult to react with the acid were gradually separated out in dispersed manner. After 20 minutes, the obtained micron-level Cu particles were separated from the solution and then cleaned and dried so as to obtain a micron-level Cu particle powder with a particle size of 1 μm to 50 μm.

Embodiment 13

[0180] This embodiment provides a method for preparing a nano-level Cu powder, which includes the following steps.

[0181] An alloy with a formulation molecular formula Pb.sub.80Cu.sub.20 was selected. Raw materials were weighed according to the formula, and subjected to vacuum induction melting to obtain an alloy melt with an ingredient Pb.sub.80Cu.sub.20. The alloy melt was prepared into Pb.sub.80Cu.sub.20 thin ribbon-like initial alloy fragments with a thickness of ˜15 μm at a rate of ˜10.sup.6K/s by using copper roller spinning and rapid-solidification method. The microstructure of the initial alloy fragments included a matrix phase composed of Pb and a dispersed particle phase composed of nano-level Cu particles. The dispersed particle phase had a particle size of 2 nm to 200 nm.

[0182] At room temperature, 0.2 g of the Pb.sub.80Cu.sub.20 initial alloy fragments prepared as above was immersed in 200 ml of an aqueous hydrochloric acid solution with a concentration of 0.5 mol/L for reaction. During the reaction, the matrix phase composed of the active element Pb reacted with an acid and entered the solution, whereas the nano-level Cu particles difficult to react with the acid were gradually separated out in dispersed manner. After 5 minutes, the obtained nano-level Cu particles were separated from the solution and then cleaned and dried so as to obtain a nano-level Cu particle powder with a particle size of 2 nm to 200 nm.

Embodiment 14

[0183] This embodiment provides a method for preparing a nano-level B powder, which includes the following steps.

[0184] An alloy with a formulation molecular formula Zn.sub.80B.sub.20 was selected. Raw materials were weighed according to the formula, and subjected to vacuum induction melting to obtain an alloy melt with an ingredient Zn.sub.80B.sub.20. The alloy melt was prepared into Zn.sub.80B.sub.20 thin ribbon-like initial alloy fragments with a thickness of 25 μm at a rate of 10.sup.5K/s by using copper roller spinning and rapid-solidification method. The microstructure of the initial alloy fragments included a matrix phase composed of Zn and a dispersed particle phase composed of nano-level B particles. The dispersed particle phase had a particle size of 2 nm to 100 nm.

[0185] At room temperature, the Zn.sub.80B.sub.20 initial alloy fragments prepared as above was immersed in an aqueous hydrochloric acid solution with a concentration of 2 mol/L for reaction. During the reaction, the matrix phase composed of Zn reacted with hydrochloric acid and entered the solution, whereas the nano-level B particles which did not react with hydrochloric acid were gradually separated out in dispersed manner. After 10 minutes, the obtained nano-level B particles were separated from the solution and then cleaned and dried so as to obtain a nano-level B particle powder with a particle size of 2 nm to 100 nm.

Embodiment 15

[0186] This embodiment provides a method for preparing a sub-micron-level B powder, which includes the following steps.

[0187] An alloy with a formulation molecular formula Zn.sub.80B.sub.20 was selected. Raw materials were weighed according to the formula, and subjected to vacuum induction melting to obtain an initial alloy melt with an ingredient Zn.sub.80B.sub.20. The initial alloy melt was prepared into Zn.sub.80B.sub.20 thin ribbon-like initial alloy fragments with a thickness of 200 μm at a rate of 10.sup.3K/s to 10.sup.4K/s by using copper roller spinning and rapid-solidification method. The microstructure of the initial alloy fragments included a matrix phase composed of Zn and a dispersed particle phase composed of sub-micron-level B particles. The dispersed particle phase had a particle size of 100 nm to 2 μm.

[0188] At room temperature, the Zn.sub.80B.sub.20 initial alloy fragments prepared as above was immersed in NaOH aqueous solution with a concentration of 5 mol/L for reaction. During the reaction, the matrix phase composed of Zn reacted with a base and entered the solution, whereas the sub-micron-level B particles which did not react with base were gradually separated out in dispersed manner. After 20 minutes, the obtained sub-micron-level B particles were separated from the solution and then cleaned and dried so as to obtain a sub-micron -level B particle powder with a particle size of 100 nm to 2 μm.

Embodiment 16

[0189] This embodiment provides a method for preparing a nano-level B powder, which includes the

[0190] An alloy with a formulation molecular formula Zn.sub.80B.sub.20 was selected. Raw materials were weighed according to the formula, and subjected to vacuum induction melting to obtain an initial alloy melt with an ingredient Zn.sub.80B.sub.20. The initial alloy melt was prepared into Zn.sub.80B.sub.20 thin ribbon-like initial alloy fragments with a thickness of 25 μm at a rate of 10.sup.5K/s by using copper roller spinning and rapid-solidification method. The microstructure of the initial alloy fragments included a matrix phase composed of Zn and a dispersed particle phase composed of nano-level B particles. The dispersed particle phase had a particle size of 2 nm to 100 nm.

[0191] At room temperature, the Zn.sub.80B.sub.20 initial alloy fragments prepared as above was placed into a vacuum tube in which a vacuum degree was maintained below 5 Pa. The vacuum tube was placed in a tubular furnace with a temperature of 400° C. During heating process, the matrix phase composed of Zn in the alloy was continuously volatilized and re-condensed in other low-temperature regions of the vacuum tube whereas the non-volatile nano-level B particles were gradually separated out in a dispersed manner. After 30 minutes, a nano-level B particle powder with a particle size of 2 nm to 100 nm was obtained.

Embodiment 17

[0192] This embodiment provides a method for preparing a nano-level Cr powder, which includes the following steps.

[0193] An alloy with a formulation molecular formula Zn.sub.85Cr.sub.15 was selected. Raw materials were weighed according to the formula, and subjected to vacuum induction melting to obtain an initial alloy melt with an ingredient Zn.sub.85Cr.sub.15. The initial alloy melt was prepared into Zn.sub.85Cr.sub.15thin ribbon-like initial alloy fragments with a thickness of 25 μm at a rate of 10.sup.5K/s by using copper roller spinning and rapid-solidification method. The microstructure of the initial alloy fragments included a matrix phase composed of Zn and a dispersed particle phase composed of nano-level Cr particles. The dispersed particle phase had a particle size of 2 nm to 100 nm.

[0194] At room temperature, the Zn.sub.85Cr.sub.15 initial alloy fragments prepared as above was immersed in an aqueous hydrochloric acid solution with a concentration of 1 mol/L for reaction. During the reaction, the matrix phase composed of Zn reacted with hydrochloric acid and entered the solution, whereas the nano-level Cr particles which did not react with the diluted aqueous hydrochloric acid solution were gradually separated out in dispersed manner. After 10 minutes, the obtained nano-level Cr particles were separated from the solution and then cleaned and dried so as to obtain a nano-level Cr particle powder with a particle size of 2 nm to 100 nm.

Embodiment 18

[0195] This embodiment provides a method for preparing a micron-level Cr powder, which includes the following steps.

[0196] An alloy with a formulation molecular formula Zn.sub.85Cr.sub.15 was selected. Raw materials were weighed according to the formula, and subjected to vacuum induction melting to obtain an initial alloy melt with an ingredient Zn.sub.85Cr.sub.15.The initial alloy melt was prepared into Zn.sub.85Cr.sub.15 sheets with a thickness of 2 mm at a rate of 300K/s by casting. The microstructure of the sheets included a matrix phase composed of Zn and a dispersed particle phase composed of micron-level Cr dendritic particles. The dispersed particle phase had a particle size of 0.5 μm to 30 μm.

[0197] At room temperature, the Zn.sub.85Cr.sub.15 initial alloy sheets prepared as above was immersed in an aqueous hydrochloric acid solution with a concentration of 1 mol/L for reaction. During the reaction, the matrix phase composed of Zn reacted with hydrochloric acid and entered the solution, whereas the micron-level Cr particles which did not react with the diluted aqueous hydrochloric acid solution were gradually separated out in dispersed manner. After 30 minutes, the obtained micron-level Cr particles were separated from the solution and then cleaned and dried so as to obtain a micron-level Cr particle powder with a particle size of 0.5 μm to 30 μm.

Embodiment 19

[0198] This embodiment provides a method for preparing a spheroidal micron-level Cr powder, which includes the following steps.

[0199] An alloy with a formulation molecular formula Zn.sub.85Cr.sub.15 was selected. Raw materials were weighed according to the formula, and subjected to vacuum induction melting to obtain an initial alloy melt with an ingredient Zn.sub.85Cr.sub.15. The initial alloy melt was prepared into Zn.sub.85Cr.sub.15 sheets with a thickness of 2 mm at a rate of 300K/s by casting. The microstructure of the sheets included a matrix phase composed of Zn and a dispersed particle phase composed of micron-level Cr dendritic particles. The dispersed particle phase had a particle size of 0.5 82 m to 30 μm.

[0200] At room temperature, the Zn.sub.85Cr.sub.15 initial alloy sheets prepared as above was immersed in an aqueous hydrochloric acid solution with a concentration of 1 mol/L for reaction. During the reaction, the matrix phase composed of Zn reacted with hydrochloric acid and entered the solution, whereas the micron-level Cr particles which did not react with the diluted aqueous hydrochloric acid solution were gradually separated out in dispersed manner. After 30 minutes, the obtained micron-level Cr particles were separated from the solution and then cleaned and dried so as to obtain a micron-level Cr particle powder with a particle size of 0.5 μm to 30 μm.

[0201] The obtained micron-level Cr particle powder was sieved such that a spheroidal micron-level Cr powder with a particle size of 5 μm to 30 μm was further obtained by performing mature plasma spheroidization.

Embodiment 20

[0202] This embodiment provides a method for preparing a sub-micron-level V powder, which includes the following steps.

[0203] An alloy with a formulation molecular formula Zn.sub.85V.sub.15 was selected. Raw materials were weighed according to the formula, and subjected to vacuum induction melting to obtain an initial alloy melt with an ingredient Zn.sub.85V.sub.15. The initial alloy melt was prepared into Zn.sub.85V.sub.15 thin ribbon-like initial alloy fragments with a thickness of 200 μm at a rate of 10.sup.3K/s˜10.sup.4K/s by using copper roller spinning and rapid-solidification method. The microstructure of the initial alloy fragments included a matrix phase composed of Zn and a dispersed particle phase composed of sub-micron-level V particles. The dispersed particle phase had a particle size of 100 nm to 2 μm.

[0204] At room temperature, the Zn.sub.85V.sub.15 initial alloy fragments prepared as above was immersed in NaOH aqueous solution with a concentration of 5 mol/L for reaction. During the reaction, the matrix phase composed of Zn reacted with a base and entered the solution, whereas the sub-micron-level V particles which did not react with the base were gradually separated out in dispersed manner. After 20 minutes, the obtained sub-micron-level V particles were separated from the solution and then cleaned and dried so as to obtain a sub-micron-level V particle powder with a particle size of 100 nm to 2 μm.

Embodiment 21

[0205] This embodiment provides a method for preparing a nano-level Mn powder, which includes the following steps.

[0206] An initial alloy with a formulation molecular formula Mg.sub.85Mn.sub.15 was selected. Raw materials were weighed according to the formula, and subjected to vacuum induction melting to obtain an initial alloy melt with an ingredient Mg.sub.85Mn.sub.15. The initial alloy melt was prepared into Mg.sub.85Mn.sub.15 thin ribbon-like initial alloy fragments with a thickness of 20 μm at a rate of 10.sup.6K/s by using copper roller spinning and rapid-solidification method. The microstructure of the initial alloy fragments included a matrix phase composed of Mg and a dispersed particle phase composed of nano-level Mn particles. The dispersed particle phase had a particle size of 2 nm to 100 nm.

[0207] At room temperature, the Mg.sub.85Mn.sub.15 initial alloy fragments prepared as above was placed into a vacuum tube in which a vacuum degree was maintained below 0.1 Pa. The vacuum tube was placed in a tubular furnace with a temperature of 600° C. During heating process, the matrix phase composed of Mg in the alloy was continuously volatilized and re-condensed in other low-temperature regions of the vacuum tube whereas the nano-level Mn particles difficult to volatilize were gradually separated out in a dispersed manner. After 0.5 h, a nano-level Mn particle powder with a particle size of 2 nm to 100 nm was obtained.

Embodiment 22

[0208] This embodiment provides a method for preparing a nano-level FeMn powder, which includes the following steps.

[0209] An alloy with a formulation molecular formula Mg.sub.80Fe.sub.10Mn.sub.10 was selected. Raw materials were weighed according to the formula, and subjected to vacuum induction melting to obtain an initial alloy melt with an ingredient Mg.sub.80Fe.sub.10Mn.sub.10. The initial alloy melt was prepared into Mg.sub.80Fe.sub.10Mn.sub.10 thin ribbon-like initial alloy fragments with a thickness of 20 μm at a rate of 10.sup.6K/s by using copper roller spinning and rapid-solidification method. The microstructure of the initial alloy fragments included a matrix phase composed of Mg and a dispersed particle phase composed of nano-level FeMn particles. The dispersed particle phase had a particle size of 2 nm to 100 nm.

[0210] At room temperature, the Mg.sub.80Fe.sub.10Mn.sub.10 initial alloy fragments prepared as above was placed into a vacuum tube in which a vacuum degree was maintained below 0.1 Pa. The vacuum tube was placed in a tubular furnace with a temperature of 600° C. During heating process, the matrix phase composed of Mg in the alloy was continuously volatilized and re-condensed in other low-temperature regions of the vacuum tube whereas the nano-level FeMn particles difficult to volatilize were gradually separated out in a dispersed manner. After 0.5 h, a nano-level FeMn particle powder with a particle size of 2 nm to 100 nm was obtained.

Embodiment 23

[0211] This embodiment provides a method for preparing a nano-level Si powder, which includes the following steps.

[0212] An initial alloy with a formulation molecular formula Zn.sub.80Si.sub.20 was selected. Raw materials were weighed according to the formula, and subjected to vacuum induction melting to obtain an initial alloy melt with an ingredient Zn.sub.80Si.sub.20. The initial alloy melt was prepared into Zn.sub.80Si.sub.20 thin ribbon-like initial alloy fragments with a thickness of 20 μm at a cooling rate of 10.sup.6K/s by using copper roller spinning and rapid-solidification method. The microstructure of the initial alloy fragments included a matrix phase composed of Zn and a dispersed particle phase composed of Nano-level Si particles. The dispersed particle phase had a particle size of 5 nm to 300 nm.

[0213] At room temperature, the Zn.sub.80Si.sub.20 initial alloy fragments prepared as above was immersed in NaOH aqueous solution with a concentration of 10 mol/L for reaction. During the reaction, the matrix phase composed of Zn reacted with a base and entered the solution, whereas the nano-level Si particles which did not react with the base were gradually separated out in dispersed manner. After 10 minutes, the obtained sub-spheroidal nano-level Si particles were separated from the solution and then cleaned and dried so as to obtain a nano-level Si particle powder with a particle size of 5 nm to 300 nm.

Embodiment 24

[0214] This embodiment provides a method for preparing a sub-micron-level Si powder, which includes the following steps.

[0215] An initial alloy with a formulation molecular formula Sn.sub.80Si.sub.20 was selected. Raw materials were weighed according to the formula, and subjected to vacuum induction melting to obtain an initial alloy melt with an ingredient Sn.sub.80Si.sub.20. The initial alloy melt was prepared into Sn.sub.80Si.sub.20 thin ribbon-like initial alloy fragments with a thickness of 150 μm at a cooling rate of 10.sup.3K/s˜10.sup.4K/s by using copper roller spinning and rapid-solidification method. The microstructure of the initial alloy fragments included a matrix phase composed of Sn and a dispersed particle phase composed of sub-micron-level Si particles. The dispersed particle phase had a particle size of 20 nm to 2 μm.

[0216] At room temperature, the Sn.sub.80Si.sub.20 initial alloy fragments prepared as above was immersed in aqueous nitric acid solution with a concentration of 0.5 mol/L for reaction. During the reaction, the matrix phase composed of the active element Sn reacted with an acid and entered the solution, whereas the sub-micron-level Si particles which did not react with the acid were gradually separated out in dispersed manner. After 20 minutes, the obtained sub-micron-level Si particles were separated from the solution and then cleaned and dried so as to obtain a sub-micron-level Si particle powder with a particle size of 20 nm to 2 μm.

Embodiment 25

[0217] This embodiment provides a method for preparing a micron-level Ge powder, which includes the following steps.

[0218] An initial alloy with a formulation molecular formula Sn.sub.75Ge.sub.25 was selected. Raw materials were weighed according to the formula, and subjected to vacuum induction melting to obtain an initial alloy melt with an ingredient Sn.sub.75Ge.sub.25. The initial alloy melt was prepared into Sn.sub.75Ge.sub.25 initial alloy at a solidification rate of 100K/s by solidification. The microstructure of the initial alloy included a matrix phase composed of Sn and a dispersed particle phase composed of micron-level Ge particles. The dispersed particle phase had a particle size of 2 μm to 120 μm.

[0219] At room temperature, the Sn.sub.75Ge.sub.25 initial alloy prepared as above was immersed in an aqueous hydrochloric acid solution with a concentration of 1 mol/L for reaction. During the reaction, the matrix phase composed of the active element Sn reacted with an acid and entered the solution, whereas the dispersed Ge particles with poor activity were gradually separated out. After 20 minutes, the obtained Ge particles were separated from the solution and then cleaned and dried so as to obtain a micron-level Ge particle powder with a particle size of 2 μm to 120 μm.

Embodiment 26

[0220] This embodiment provides a method for preparing a nano-level Si-Ge powder, which includes the following steps.

[0221] An initial alloy with a formulation molecular formula Zn.sub.80Si.sub.10Ge.sub.10 was selected. Raw materials were weighed according to the formula, and subjected to vacuum induction melting to obtain an initial alloy melt with an ingredient Zn.sub.80Si.sub.10Ge.sub.10. The initial alloy melt was prepared into Zn.sub.80Si.sub.10Ge.sub.10 thin ribbon-like initial alloy fragments with a thickness of 20 μm at a cooling rate of 10.sup.6K/s by using copper roller spinning and rapid-solidification method. The microstructure of the initial alloy fragments included a matrix phase composed of Zn and a dispersed particle phase composed of nano-level Si—Ge particles. The dispersed particle phase had a particle size of 5 nm to 300 nm.

[0222] At room temperature, the Zn.sub.80Si.sub.10Ge.sub.10 initial alloy fragments prepared as above was immersed in an aqueous hydrochloric acid solution with a concentration of 1 mol/L for reaction. During the reaction, the matrix phase composed of the active element Zn reacted with an acid and entered the solution, whereas the nano-level Si—Ge particles which did not react with the acid solution were gradually separated out in dispersed manner. After 10 minutes, the obtained sub-spheroidal nano-level Si—Ge particles were separated from the solution and then cleaned and dried so as to obtain a nano-level Si—Ge particle powder with a particle size of 5 nm to 300 nm.

Embodiment 27

[0223] This embodiment provides a method for preparing a sub-micron-micron-level Fe powder, which includes the following steps.

[0224] Fe sheets and rare earth La raw materials with the atomic percent contents of an impurity element T (including O, H, N, P, S, F, Cl, Br and I) being 1 at. % and 2.5 at. % respectively were selected. The alloy raw materials were melted according to the molar ratio of La:Fe which was about 2:1, so as to obtain a homogeneous initial alloy melt with a major atomic percent ingredient being La.sub.65.3Fe.sub.32.7T.sub.2.

[0225] The initial alloy melt was prepared into a La.sub.65.3Fe.sub.32.7T.sub.2 alloy ribbon with a thickness of ˜100 μm at a solidification rate of about ˜10.sup.4K/s by using copper roller spinning technology. The solidification structure of the alloy ribbon was composed of a matrix phase with a major atomtic percent ingredient being La.sub.97.2T.sub.2.8 and a dispersed particle phase with a major ingredient being Fe.sub.99.7T.sub.0.3. The shape of the Fe.sub.99.7T.sub.0.3 dispersed particles was sub-spheroidal or dendritic, with its particle size of 500 nm to 3 μm. The volume percent content of the Fe.sub.99.7T.sub.0.3 dispersed particles in the alloy ribbon was about 14%. The La.sub.97.2T.sub.2.8 matrix phase in the alloy ribbon was removed by using a dilute acid solution, while the separated Fe.sub.99.7T.sub.0.3 dispersed particles were separated from the dilute acid solution quickly by using Fe magnetism, so as to obtain a sub-micron-micron-level powder with the major ingredient of Fe.sub.99.7T.sub.0.3, which had a particle size of 500 nm to 3 μm. The total content of O, H, N, P, S, F, Cl, Br and I contained therein was 0.3 at. %.

[0226] The obtained sub-micron-micron-level Fe powder can be used in magnetic materials.

Embodiment 28

[0227] This embodiment provides a method for preparing a nano-level Fe powder, which includes the following steps.

[0228] Fe sheets and rare earth La raw materials with the atomic percent contents of an impurity element T (including O, H, N, P, S, F, Cl, Br and I) being 1 at. % and 2.5 at. % respectively were selected. The alloy raw materials were melted according to the molar ratio of La:Fe which was about 60:40, so as to obtain a homogeneous initial alloy melt with a major atomic percent ingredient being La.sub.58.5Fe.sub.39.6T.sub.1.9.

[0229] The initial alloy melt was prepared into a La.sub.58.5Fe.sub.39.6T.sub.1.9 alloy ribbon with a thickness of ˜20 μm at a solidification rate of about ˜10.sup.6K/s by using copper roller spinning technology. The solidification structure of the alloy ribbon was composed of a matrix phase with a major atomtic percent ingredient being La.sub.97T.sub.3 and a dispersed particle phase with a major ingredient being Fe.sub.99.75T.sub.0.25. The shape of the Fe.sub.99.75T.sub.0.25dispersed particles was sub-spheroidal, with its particle size of 20 nm to 200 nm. The volume percent content of the Fe.sub.99.75T.sub.0.25 dispersed particles in the alloy ribbon was about 17.5%.

[0230] By using the natural oxidation-powdering process of La in the air and the magnetism of Fe particles, the Fe particles were separated from an oxide generated by La powdering so as to obtain a nano-level Fe particle with its particle size of 20 nm to 200 nm. The total content of O, H, N, P, S, F, Cl, Br and I contained in the nano-level Fe powder was 0.25 at. %.

Embodiment 29

[0231] This embodiment provides a method for preparing a nano-level Fe powder, which includes the following steps.

[0232] Fe sheets and rare earth La raw materials with the atomic percent contents of an impurity element T (including O, H, N, P, S, F, Cl, Br and I) being 1 at. % and 2.5 at. % respectively were selected. The La raw material further contains 1 at. % of Ce, and the Fe raw material further contains 0.5 at. % of Mn. The alloy raw materials were melted according to the molar ratio of La:Fe which was about 60:40, so as to obtain a homogeneous initial alloy melt with a major atomic percent ingredient being (La.sub.99Ce.sub.1).sub.58.5(Fe.sub.99.5Mn.sub.0.5).sub.39.6T.sub.1.9.

[0233] The initial alloy melt was prepared into a (La.sub.99Ce.sub.1).sub.58.5(Fe.sub.99.5Mn.sub.0.5).sub.39.6T.sub.1.9 alloy ribbon with a thickness of ˜20 μm at a solidification rate of about ˜10.sup.6K/s by using copper roller spinning technology. The solidification structure of the alloy ribbon was composed of a matrix phase with a major atomtic percent ingredient being (La.sub.99Ce.sub.1).sub.97T.sub.3 and a dispersed particle phase with a major ingredient being (Fe.sub.99.5Mn.sub.0.5).sub.99.75T.sub.9.25. The shape of the (Fe.sub.99.5Mn.sub.0.5).sub.99.75T.sub.0.25 dispersed particles was sub-spheroidal, with its particle size of 20 nm to 200 nm. The volume percent content of the (Fe.sub.99.5Mn.sub.0.5).sub.99.75T.sub.0.25 dispersed particles in the alloy ribbon was about 17.5%. Moreover, the introduction of Mn and Ce into the alloy melt does not cause generation of an intermetallic compound composed of La, Ce and Fe, Mn in the initial alloy ribbon; Further, the introduction does not affect the structural characteristics of the matrix phase and the dispersed particle phase in the alloy ribbon and the law of decrease of the impurity content of the dispersed particle phase.

[0234] By using the natural oxidation-powdering process of La in the air and the magnetism of Fe particles, the (Fe.sub.99.5Mn.sub.0.5).sub.99.75T.sub.0.25 particles were separated from an oxide generated by La powdering so as to obtain a nano-level (Fe.sub.99.5Mn.sub.0.5).sub.99.75T.sub.0.25 particle with its particle size of 20 nm to 200 nm. The total content of O, H, N, P, S, F, Cl, Br and I contained in the nano-level (Fe.sub.99.5Mn.sub.0.5).sub.99.75T.sub.0.25 powder was 0.25 at. %

[0235] The technical features of the above embodiments may be arbitrarily combined. For the purpose of conciseness of depiction, all possible combinations of the technical features of the above embodiments are not described. However, as long as there is no contradiction in the combinations of these technical features, they shall be considered to be within the scope of the present disclosure.

[0236] The above embodiments only show several implementations of the present disclosure, which are described in details. But, the detailed descriptions shall not be understood as limitation to the scope of the present disclosure. It should be noted that, for ordinary persons skilled the prior arts, a number of variations and improvements can be made without departing from the concept of the present disclosure and shall all fall within the scope of protection of the present disclosure. Therefore, the scope of protection of the present disclosure shall be subjected to the appended claims.