CN113579246A - Preparation method of nano high-entropy alloy powder - Google Patents

Abstract

Translated fromChinese

本发明属于金属粉末加工领域，具体公开了一种纳米高熵合金粉末的制备方法，包括：将五种以上的过渡金属盐前驱体溶解于同一溶剂并超声分散得到共混溶液；对共混溶液加入强碱溶液进行共沉淀反应后，在60‑180℃的温度下进行陈化，然后分离出沉淀混合物并依次进行水洗、醇洗、干燥；在400‑800℃的温度以及空气气氛中，对过渡金属氢氧化物混合物进行煅烧，得到过渡金属氧化物；在300‑600℃的温度以及氢气/一氧化碳气氛中，对过渡金属氧化物进行还原反应，即得纳米高熵合金粉末。本发明提供的纳米高熵合金粉末的制备方法不仅具有工艺简单、流程短的特点，而且适用于大批量制备不同成分的纳米高熵合金，易于工业化。

The invention belongs to the field of metal powder processing, and specifically discloses a method for preparing nanometer high-entropy alloy powder, comprising: dissolving more than five transition metal salt precursors in the same solvent and ultrasonically dispersing to obtain a blended solution; After adding a strong base solution to carry out co-precipitation reaction, ageing is carried out at a temperature of 60-180 ℃, and then the precipitation mixture is separated and washed with water, alcohol, and dried in sequence; at a temperature of 400-800 ℃ and an air atmosphere, the The transition metal hydroxide mixture is calcined to obtain a transition metal oxide; at a temperature of 300-600° C. and a hydrogen/carbon monoxide atmosphere, the transition metal oxide is subjected to a reduction reaction to obtain a nanometer high-entropy alloy powder. The preparation method of nanometer high-entropy alloy powder provided by the invention not only has the characteristics of simple process and short process, but also is suitable for preparing nanometer high-entropy alloys with different components in large quantities, and is easy to be industrialized.

Description

Preparation method of nano high-entropy alloy powder

Technical Field

The embodiment of the application relates to the technical field of metal powder processing, in particular to a preparation method of nano high-entropy alloy powder.

Background

The high-entropy alloy (HEAS) is a novel alloy formed by five or more metals with equal atomic ratio or near equal atomic ratio, and the synergistic effect of a plurality of main elements enables the high-entropy alloy to have higher mixed entropy, larger lattice distortion energy, slow diffusion effect and cocktail effect, so that the high-entropy alloy has a plurality of excellent properties, such as higher strength, hardness, toughness, oxidation resistance, adsorption property and the like. Based on the characteristics, the high-entropy alloy has great potential application value in a plurality of fields, for example, the properties of strength, hardness and the like of the material can be improved by spraying the nano high-entropy alloy powder on the surface of the material; the nano high-entropy alloy powder has excellent catalytic performance and can be used for catalyzing chemical reactions such as methanol oxidation and oxygen evolution; the nanometer high-entropy alloy has large lattice distortion and a plurality of active sites, and can be used for storing hydrogen. In addition, the rapid development of additive manufacturing technology (3D printing) and powder metallurgy technology also provides a new development direction for the application of nano high-entropy alloy powder.

At present, the preparation method of the high-entropy alloy powder mainly comprises the following steps: 1) the vacuum melting method is a process of putting pure metal into a crucible, repeatedly vacuumizing the crucible in a vacuum furnace, filling argon as protective gas, and casting and forming the pure metal in a water-cooled copper mold after the pure metal is completely and uniformly melted, but the thermal expansion and condensation in the casting process easily cause the defects of large internal stress, composition segregation, gaps, shrinkage cavities and the like of cast alloy, the performance of the high-entropy alloy is influenced, the problems of large particle size and non-uniform particle size of powder are easily caused when the cast ingot is crushed into powder, and the melting process is relatively complex; 2) the powder metallurgy method is a process for manufacturing a powder metallurgy product by pressing, forming and calcining metal or nonmetal powder serving as a raw material, can be used for manufacturing special materials which are difficult to prepare by using a common smelting method, has high utilization rate of the materials, has certain limit on the size and the shape of a cast alloy, is difficult to control the structure and the performance of a high-entropy alloy, and easily causes the problems of large particle size and nonuniform particle size of the powder when an ingot is crushed into powder; 3) the mechanical alloying method (ball milling) is a process for realizing solid alloying by the fact that alloy powder is in a high-energy ball mill, powder particles and grinding balls are subjected to long-time violent impact collision, and the powder particles are repeatedly subjected to cold welding and fracture to cause atomic diffusion in the powder particles, but the mechanical alloying is used as a solid processing process, the selection range for preparing high-entropy alloy elements is not wide enough, the granularity of the high-entropy alloy powder prepared by the mechanical alloying method is not uniform enough, the size of the high-entropy alloy powder is relatively large, and the powder preparation efficiency is low.

In view of the above, there is a need to develop a nano high-entropy alloy with wide element selection range, simple process, high production efficiency, and controllable purity and particle size of alloy powder.

Disclosure of Invention

The embodiment of the application aims to provide a method for preparing nano high-entropy alloy powder, which is used for preparing the nano high-entropy alloy powder by a technical means of combining coprecipitation and hydrogen and/or carbon monoxide reduction and solves the technical problems of complex process, long flow, low powder purity and large particle size of the existing method for preparing the high-entropy alloy powder.

In order to achieve the above purpose, the technical solution of the embodiment of the present application is:

the embodiment of the application provides a preparation method of nano high-entropy alloy powder, which comprises the following steps:

dissolving more than five transition metal salt precursors in the same solvent, and performing ultrasonic dispersion after dissolving to obtain a blending solution, wherein transition metal oxides generated by transition metals in the transition metal salt precursors can be reduced by hydrogen and/or carbon monoxide;

adding a strong base solution into the blending solution and fully stirring to enable the transition metal salt precursor to perform coprecipitation reaction to completely generate a transition metal hydroxide precipitation mixture;

aging the reaction system of the transition metal salt precursor at the temperature of 60-180 ℃ for 6-48h, separating out the generated transition metal hydroxide precipitate mixture, and sequentially performing water washing, alcohol washing and drying treatment on the transition metal hydroxide precipitate mixture to obtain a transition metal hydroxide mixture;

calcining the transition metal hydroxide mixture at the temperature of 400-800 ℃ and in an air atmosphere for 2-10h to obtain a transition metal oxide; and then carrying out reduction reaction on the transition metal oxide for 1-2h at the temperature of 300-600 ℃ and in the atmosphere of hydrogen and/or carbon monoxide to obtain the nano high-entropy alloy powder.

In some possible preferred embodiments of the present application, before the ultrasonic dispersion of the transition metal salt precursor solution, polyvinylpyrrolidone and activated carbon are further added to the transition metal salt precursor solution.

In some possible preferred embodiments of the present application, the coprecipitation reaction of the transition metal salt precursor is performed at a temperature of 40 to 80 ℃, and the time of the coprecipitation reaction is 0.5 to 2.5 hours.

In some possible preferred embodiments of the present application, the transition metal salt precursor includes any one of a transition metal nitrate, a transition metal sulfate, and a transition metal chloride.

In some possible preferred embodiments of the embodiments herein, the solvent comprises any one of methanol, ethanol, or deionized water.

In some possible preferred embodiments of the present application, the strong alkaline solution includes any one of a sodium hydroxide solution and a potassium hydroxide solution.

In some possible preferred embodiments of the present application, the transition metal salt precursor includes NiCl₂•6H₂O、FeCl₂•4H₂O、CuCl₂•2H₂O、CoCl₂•6H₂O、H₂PtCl₆•6H₂O。

In some possible preferred embodiments of the present application, the transition metal salt precursor further comprises CrCl₃·6H₂O

In some possible preferred embodiments of the present application, the nano high-entropy alloy powder is stored in an inert gas atmosphere.

In some possible preferred embodiments of the present application, the transition metal salt precursor comprises AgNO₃、H₂PtCl₆•6H₂O、HAuCl₄、CuCl₂•2H₂O、Na₂PdCl₄。

Compared with the prior art, the advantages or beneficial effects of the embodiments of the present application at least include:

according to the preparation method of the nanometer high-entropy alloy powder, after more than five transition metal salt precursors are dissolved in the same solvent for blending, a strong base solution is added for coprecipitation reaction and temperature-controlled aging to generate a transition metal hydroxide mixture, the transition metal hydroxide mixture is calcined at the temperature of 400-800 ℃ in the air atmosphere, and is reduced at the temperature of 300-600 ℃ in the hydrogen and/or carbon monoxide atmosphere, so that the nanometer high-entropy alloy powder with complete crystal form and uneven particle size is prepared. In view of this, in the embodiments of the present application, a transition metal salt precursor is used as a metal raw material, and a comprehensive technology of "coprecipitation-aging-calcination-hydrogen and/or carbon monoxide reduction" is adopted to prepare a nano high-entropy alloy powder, so that it is not limited to use pure metal powder as a raw material, and transition metals capable of reducing their oxides by hydrogen and/or carbon monoxide can be used as raw materials for preparing high-entropy alloys, thereby expanding the selection range of metal elements. Meanwhile, the high-entropy alloy prepared by coprecipitation, aging, calcination and reduction reaction of the transition metal salt has higher metal purity, can effectively solve the problem that part of pure metal powder raw materials are easy to cause component segregation due to impurity content, and realizes the improvement of the utilization rate of the metal raw materials and the improvement of the metal purity of the high-entropy alloy powder. In addition, in the processes of coprecipitation, aging, calcination and reduction reaction of the transition metal salt precursor, the crystal form and the particle size of the high-entropy alloy powder can be controlled by regulating and controlling process parameters (such as aging temperature and/or time, calcination temperature and/or time and the like), so that the control of the structure and the performance of the high-entropy alloy is realized.

According to the preparation method of the nano high-entropy alloy powder, the transition metal salt precursor is subjected to coprecipitation, aging, calcining and reduction reaction to prepare the nano high-entropy alloy, the preparation method has the characteristics of simple process and short flow, the reaction conditions of each step are relatively mild, and the preparation method is suitable for preparing the nano high-entropy alloy with different components in a large scale and is easy for industrialization.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings used in the description of the embodiments will be briefly introduced below. It is obvious that the drawings in the following description are only some of the embodiments described in the present application, and that other drawings can be derived from these drawings by a person skilled in the art without inventive effort.

FIG. 1 is a flow chart of a method for preparing nano high-entropy alloy powder provided by an embodiment of the application;

FIG. 2 is an X-ray diffraction pattern of FeCoNiCuPt-1 nano high-entropy alloy powder provided by an embodiment of the present application;

FIG. 3 is a scanning electron microscope image of FeCoNiCuPt-1 high-entropy alloy powder provided by the embodiment of the present application;

FIG. 4 is a transmission electron microscope image of FeCoNiCuPt-1 high-entropy alloy powder provided by the embodiment of the present application;

FIG. 5 is an X-ray diffraction pattern of FeCoNiCuPt-2 high-entropy alloy powder provided by an embodiment of the present application;

FIG. 6 is a scanning electron microscope image of FeCoNiCuPt-2 high-entropy alloy powder provided by the embodiment of the present application;

FIG. 7 is a transmission electron microscope image of FeCoNiCuPt-2 high-entropy alloy powder provided by the embodiment of the present application;

FIG. 8 is a graph showing the variation of grain size of high-entropy alloy powder with aging temperature when the aging time is controlled to be 12 hours;

FIG. 9 is a graph showing the variation of grain size of high-entropy alloy powder with aging temperature when the aging temperature is controlled to 80 ℃;

FIG. 10 is a curve of the variation of the grain size of the high-entropy alloy powder with the calcination temperature when the calcination time is controlled to be 2 h;

FIG. 11 is a graph showing the variation of the particle size of the high-entropy alloy powder with the calcination time while controlling the calcination temperature to 400 ℃.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the embodiments of the present application. It should be apparent that the embodiments described below are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In order to solve the problems of complex process, long flow, low powder purity and large particle size of the existing preparation method of the high-entropy alloy powder, the embodiment provides a preparation method of the nanometer high-entropy alloy powder.

As shown in FIG. 1, the preparation method of the nano high-entropy alloy powder comprises steps S101-S104.

S101: dissolving more than five transition metal salt precursors in the same solvent, and performing ultrasonic dispersion after dissolving to obtain a blended solution, wherein transition metal oxides generated by transition metals in the transition metal salt precursors can be reduced by hydrogen and/or carbon monoxide.

In the present embodiment, the preparation of the nano high-entropy alloy powder using five or more transition metal salt precursors as the metal raw materials is not limited to the pure metal powder required in the vacuum melting method, the powder metallurgy method, and the mechanical alloying method. Therefore, all transition metal elements whose oxides can be reduced by hydrogen and/or carbon monoxide are suitable, and particularly some transition metal elements with unstable chemical properties are also suitable, so that the selection range of the transition metal elements is expanded. For example, in the present embodiment, any five or more transition metal elements selected from Fe, Co, Ni, Cu, Mn, Cr, Zn, W, Ag, Ir, Au, Rh, and Pt can be selected.

However, it will be understood by those skilled in the art that in order to ensure that five or more transition metal salt precursors can be co-precipitated in the desired ratio to form the corresponding transition metal hydroxide precipitation mixture, the five or more transition metal salt precursors must be completely dissolved in the same solvent. In this respect, in the present embodiment, any one of the transition metal nitrate, the transition metal sulfate and the transition metal chloride having relatively good solubility is preferably used as the transition metal saltThe precursor, and the transition metal nitrate, the transition metal sulfate and the transition metal chloride can be dissolved in organic solvents such as methanol, ethanol and the like and water in general, but the tap water contains metal impurity ions such as Ca²⁺、Mg²⁺Etc. may interfere with the coprecipitation reaction, and thus the solvent in this embodiment is preferably any one of methanol, ethanol, or deionized water.

In addition, the five or more transition metal salt precursors in this example were based on the molar ratio of the transition metal elements being 1:1:1:1:1 … ….

Meanwhile, in this embodiment, before the ultrasonic dispersion of the transition metal salt precursor solution, polyvinylpyrrolidone and activated carbon are added to the transition metal salt precursor solution, so as to control the grain size of the transition metal hydroxide precipitate mixture. Specifically, the polyvinylpyrrolidone is an organic macromolecular chain, the activated carbon is a carrier with a large specific surface area, and both the polyvinylpyrrolidone and the activated carbon do not participate in the coprecipitation reaction and are helpful for inhibiting the growth of crystal grains of the precipitation mixture of the transition metal hydroxide.

S102: and adding a strong base solution into the blending solution and fully stirring to ensure that the transition metal salt precursor is subjected to coprecipitation reaction to completely generate a transition metal hydroxide precipitation mixture.

It should be understood by those skilled in the art that in the present embodiment, a strong alkali solution is used as a precipitant, which is capable of performing a coprecipitation reaction with more than five transition metal salt precursors to generate a hydroxide precipitate mixture, in order to prevent the strong alkali solution and the transition metal salt precursors from generating impurity precipitates (such as barium sulfate) during the coprecipitation reaction, and to ensure that the added strong alkali solution can be completely dissolved in the blending solution and participate in the coprecipitation reaction, therefore, it is preferable that the strong alkali solution is any one of a sodium hydroxide solution and a potassium hydroxide solution in the present embodiment.

Based on the above description, in the preparation process of FeCoNiCuPt nano high-entropy alloy powder, when the transition metal salt precursor and the strong base solution are subjected to a coprecipitation reaction, the following ionic reactions occur:

Ni²⁺ + 2OH^– → Ni(OH)₂↓

Fe²⁺ + 2OH^– → Fe(OH)₂↓

Co²⁺ + 2OH^– → Co(OH)₂↓

Cu²⁺ + 2OH^– → Cu(OH)₂↓

Pt⁴⁺ + 4OH^– → Pt(OH)₄↓

in addition, the temperature is increased to help the transition metal salt precursor to be rapidly and completely dissolved and control the particle growth of the transition metal hydroxide precipitation mixture, the coprecipitation reaction of the transition metal salt precursor is carried out at the temperature of 40-80 ℃, and the time of the coprecipitation reaction is 0.5-2.5 h.

S103: and aging the reaction system of the transition metal salt precursor at the temperature of 60-180 ℃ for 6-48h, separating out the generated transition metal hydroxide precipitate mixture, and sequentially washing the transition metal hydroxide precipitate mixture with water for three times, washing with alcohol for three times and drying to obtain the transition metal hydroxide mixture.

It will be understood by those skilled in the art that the temperature has a significant effect on the grain growth of the transition metal hydroxide precipitation mixture, and this example analyzes the effect of different aging temperatures and aging times on the grain size of the high-entropy alloy powder by using a one-factor variable method, as shown in fig. 8 to 9. Wherein, FIG. 8 is a variation curve of the grain size of the high-entropy alloy powder with aging temperature when the aging time is controlled to be 12 h; FIG. 9 is a graph showing the variation of particle size of high-entropy alloy powder with aging temperature when the aging temperature is controlled to 80 ℃.

As can be seen from fig. 8, under the condition of the aging time of 12 hours, when the aging temperature is lower than 60 ℃, the high-entropy alloy powder with uniform particle size distribution cannot be obtained, and part of the transition metal elements may not form the high-entropy alloy; when the aging temperature is 60-180 ℃, the grain size distribution uniformity of the high-entropy alloy powder is good, and the grain size of the high-entropy alloy powder is increased along with the increase of the aging temperature, and the grain size distribution of the high-entropy alloy powder is between 40-170 nm; when the aging temperature is higher than 180 ℃, the pressure generated by vaporization of the solvent is large, and the performance requirement on reaction equipment (such as a high-pressure reaction kettle) is high, so that the cost is increased. Therefore, this example is preferably aged at a temperature of 60 to 180 ℃.

As can be seen from fig. 9, under the condition that the aging temperature is 80 ℃, when the aging time is less than 6 hours, the high-entropy alloy powder with complete crystal form and uniform particle size distribution cannot be obtained; when the aging time is longer than 6 hours, the crystal form of the high-entropy alloy powder is complete and the particle size distribution is uniform, and meanwhile, the particle size of the high-entropy alloy powder is increased along with the increase of the aging time, but the aging time is too long, so that the time cost is increased, and the high-entropy alloy powder is micronized. Therefore, the preferred aging time for this example is 6-48 h.

It should be noted that the reaction system of the transition metal salt precursor described in this embodiment refers to a system in which the transition metal salt precursor and the strong base solution undergo a coprecipitation reaction, and includes a generated precipitation mixture of the transition metal hydroxide. Wherein, the aging can be carried out in a high-pressure hydrothermal kettle.

In addition, the solvent for dissolving the transition metal salt precursor and the water and alcohol remaining during the water washing and the alcohol washing are adsorbed in the transition metal hydroxide mixture after aging, and the crystal grain shape of the transition metal hydroxide mixture may be affected by the uneven precipitation of the solvent adsorbed in the transition metal hydroxide mixture and the water and alcohol remaining in the transition metal hydroxide mixture, so that vacuum drying is preferred in this embodiment.

S104: calcining the transition metal hydroxide mixture at the temperature of 400-800 ℃ and in an air atmosphere for 2-10h to obtain a transition metal oxide mixture; and then carrying out reduction reaction on the transition metal oxide mixture for 1-2h at the temperature of 300-600 ℃ and in the atmosphere of hydrogen and/or carbon monoxide to obtain the nano high-entropy alloy powder.

It will be appreciated by those skilled in the art that the hydroxide precipitate mixture is calcined in an air atmosphere which not only removes residual solvent, water, alcohol, etc. from the hydroxide precipitate mixture, but also dehydrates the hydroxide precipitate mixture to form a transition metal oxide mixture in which a portion of the transition metal oxide may be further oxidized.

Based on the above description, Ni (OH) is generated in the preparation process of FeCoNiCuPt nano high-entropy alloy powder₂、Fe(OH)₂、Co(OH)₂、Cu(OH)₂、Pt(OH)₄When the calcination is carried out in an air atmosphere, the chemical reactions that occur therein are as follows:

Ni(OH)₂ → NiO + H₂O

Fe(OH)₂ → FeO + H₂O

Co(OH)₂ → CoO + H₂O

Cu(OH)₂ → CuO + H₂O

Pt(OH)₄ → PtO₂ + 2H₂O

in which the FeO and CoO produced by calcination are further oxidized by the following chemical reactions:

4FeO + O₂ → 2Fe₂O₃

6CoO + O₂ → 2Co₃O₄

it will be appreciated by those skilled in the art that not only is it necessary to adjust the particle size of the high entropy alloy powder produced by controlling the calcination temperature and calcination time, but the calcination temperature and calcination time are also controlled to ensure that all entrained activated carbon and residual organics in the transition metal oxide mixture are eliminated. This example analyzes the effect of different calcination temperatures on the high-entropy alloy powder by a one-factor variable method, and the results are shown in fig. 10 and 11. Wherein, FIG. 10 is a variation curve of the grain size of the high-entropy alloy powder with the calcination temperature when the calcination time is controlled to be 2 h; FIG. 11 is a graph showing the variation of the particle size of the high-entropy alloy powder with the calcination time while controlling the calcination temperature to 400 ℃.

According to fig. 10, under the condition of calcination time of 2h, when the calcination temperature is lower than 400 ℃, high-entropy alloy powder with complete crystal form and uniform particle size distribution cannot be obtained, and activated carbon and residual organic matters in the high-entropy alloy powder cannot be completely eliminated; when the calcination temperature is higher than 400 ℃, the crystal form of the high-entropy alloy powder is complete and the particle size distribution is uniform, and meanwhile, as the calcination temperature rises, the particle size of the high-entropy alloy powder is increased, but the high-entropy alloy powder is micronized due to overhigh calcination temperature, and meanwhile, heat resources are wasted. Therefore, the calcination temperature is preferably 400-800 ℃ in the embodiment, and the particle size of the prepared high-entropy alloy powder is 70-210 nm.

According to fig. 11, under the condition of the calcination temperature of 400 ℃, when the calcination time is less than 2 hours, the activated carbon and the residual organic matters in the high-entropy alloy powder cannot be completely eliminated, so that the crystal structure and the purity quality of the high-entropy alloy powder are poor; when the calcination time is longer than 2 hours, the activated carbon and residual organic matters in the high-entropy alloy powder can be completely eliminated, so that the high-entropy alloy powder is good in purity and quality, complete in crystal form and uniform in particle size distribution, the particle size of the high-entropy alloy powder is increased along with the increase of the calcination time, and the high-entropy alloy powder is micronized and the time cost is increased due to the fact that the calcination time is too long. Therefore, the calcination time of this example is preferably 2 to 10 hours.

Further, the transition metal oxide mixture generated by calcination is reduced in hydrogen and/or carbon monoxide atmosphere, and then the nano high-entropy alloy powder can be formed.

It should be understood by those skilled in the art that the reduction temperature and the reduction time are required to ensure that the metal oxide can be completely reduced, and the reduction temperature of the metal oxide can be reduced by the mixed effect of multiple elements, and in this embodiment, the nano high-entropy alloy powder is obtained by reduction at the reduction temperature of 300-600 ℃ and the reduction time of 1-2 hours. Therefore, based on the need for the metal oxide to be able to be completely reduced and cost considerations, the present embodiment preferably performs the reduction at a temperature of 300-600 ℃ and in a hydrogen and/or carbon monoxide atmosphere for a reduction time of 1-2 hours.

It should be noted that, in the process of coprecipitation, aging, calcination and reduction of the transition metal salt precursor, not only impurities are removed, but also the transition metal in the transition metal salt precursor can be completely converted to generate the nano high-entropy alloy powder, so that the purity of the nano high-entropy alloy powder is improved.

Based on the above description, in the preparation process of FeCoNiCuPt nano high-entropy alloy powderNiO, CuO and PtO generated by calcination₂、Fe₂O₃、Co₃O₄When the reduction is carried out in a hydrogen atmosphere, the chemical reactions which occur therein are as follows:

NiO + H₂ → Ni + H₂O

CuO + H₂ → Cu+ H₂O

PtO₂ + 2H₂ → Pt + 2H₂O

Fe₂O₃ + 3H₂ → 2Fe + 3H₂O

Co₃O₄ + 4H₂ → 3Co + 4H₂O

in summary, in this embodiment, after more than five transition metal salt precursors are dissolved in the same solvent and blended, polyvinylpyrrolidone, activated carbon and a strong base solution are added to perform a coprecipitation reaction and temperature-controlled aging to generate a transition metal hydroxide mixture, the transition metal hydroxide mixture is calcined at a temperature of 400 ℃. sup. 800 ℃ in an air atmosphere, and is reduced at a temperature of 300 ℃. sup. 600 ℃ in a hydrogen and/or carbon monoxide atmosphere, so that the nano high-entropy alloy powder with complete crystal form and uniform size distribution is prepared under the conditions of inhibiting excessive growth of crystal grains in the coprecipitation reaction and aging process and ensuring uniform distribution of metal elements. In view of this, in the embodiments of the present application, a transition metal salt precursor is used as a metal raw material, and a comprehensive technology of "coprecipitation-aging-calcining-hydrogen and/or carbon monoxide reduction" is used to prepare a nano high-entropy alloy powder, which is not limited to pure metal powder as a raw material, and all transition metals capable of being reduced by hydrogen and/or carbon monoxide to their oxides can be used as a raw material for preparing a high-entropy alloy, thereby expanding the selection range of metal elements. Meanwhile, the high-entropy alloy prepared by the transition metal salt through coprecipitation, aging, calcination and reduction reactions has higher metal purity, can effectively solve the problem that part of pure metal powder raw materials are easy to cause component segregation due to the inclusion of impurities, and realizes the improvement of the utilization rate of the metal raw materials and the improvement of the metal purity of the high-entropy alloy powder. In addition, in the processes of coprecipitation, aging, calcination and reduction reaction of the transition metal salt precursor, the crystal form and the particle size of the high-entropy alloy powder can be controlled by regulating and controlling process parameters (such as aging temperature and/or time, calcination temperature and/or time and the like), so that the control of the structure and the performance of the high-entropy alloy is realized. On the other hand, after the transition metal salt precursor is subjected to coprecipitation, aging, calcination and reduction reactions, the nano high-entropy alloy can be prepared, and the method has the characteristics of simple process and short flow, and relatively mild reaction conditions of each step, is suitable for preparing the nano high-entropy alloy with different components in a large scale, and is easy for industrialization.

In some specific embodiments of this example, FeCoNiCuPt nano high-entropy alloy powder can be prepared, wherein the precursor of the transition metal salt is 72.76mgNiCl₂•6H₂O、59.88mgFeCl₂•4H₂O、51.68mgCuCl₂•2H₂O、71.12mg CoCl₂•6H₂O、3ml(0.1M)H₂PtCl6•6H₂And (C) O.

In some specific embodiments of this example, FeCoNiCuCrPt nano high-entropy alloy powder can be prepared, wherein the precursor of the transition metal salt is 72.76mgNiCl₂•6H₂O、59.88mgFeCl₂•4H₂O、51.68mgCuCl₂•2H₂O、71.12mgCoCl₂•6H₂O、83.27mgCrCl₃•6H₂O、3ml(0.1M)H₂PtCl6•6H₂And (C) O.

In some specific embodiments of this example, AgAuPtCuPd nano high-entropy alloy powder can be prepared, wherein the precursor of the transition metal salt is 51.48mgAgNO₃、3ml(0.1M)H₂PtCl₆•6H₂O、3ml(0.1M)HAu•Cl₄、51.68mgCuCl₂•2H₂O、89.15mgNa₂PdCl_l4And (4) forming.

The technical solution of the present invention will be further described with reference to the following specific examples.

Example 1

Theembodiment 1 provides a preparation method of FeCoNiCuPt nano high-entropy alloy powder, which includes the following steps:

taking the molar ratio of the transition metal elements as 1:1:1:1:1, weighing the transition metal salt precursor according to the dosage of 0.3mmol of each transition metal element, and concretely, 72.76mg NiCl₂•6H₂O、59.88mgFeCl₂•4H₂O、51.68mgCuCl₂•2H₂O、71.12mgCoCl₂•6H₂O、3mL(0.1M)H₂PtCl₆•6H₂Adding O and 85.5mg of polyvinylpyrrolidone into 40mL of ethanol solvent, stirring and dissolving in a constant-temperature water bath at 60 ℃, adding 18mg of activated carbon, and performing ultrasonic dispersion for 10min to obtain a blending solution;

dropwise adding 10mL (1M) of NaOH solution into the blending solution in a thermostatic water bath at 60 ℃ and stirring, and continuously stirring for 2h to ensure that the transition metal salt precursor is subjected to coprecipitation reaction to completely generate Fe (OH)₂、Ni(OH)₂、Co(OH)₂、Cu(OH)₂And Pt (OH)₄Precipitating the mixture;

transferring the reaction system of the transition metal salt precursor into a hydrothermal kettle at 80 ℃ for aging for 12h, and then separating out the generated Fe (OH)₂、Ni(OH)₂、Co(OH)₂、Cu(OH)₂And Pt (OH)₄Precipitating the mixture and adding Fe (OH)₂、Ni(OH)₂、Co(OH)₂、Cu(OH)₂And Pt (OH)₄Washing the precipitate mixture with water and ethanol for three times, and vacuum drying for 12h to obtain Fe (OH)₂、Ni(OH)₂、Co(OH)₂、Cu(OH)₂And Pt (OH)₄Mixing;

in an air atmosphere, Fe (OH)₂、Ni(OH)₂、Co(OH)₂、Cu(OH)₂And Pt (OH)₄Calcining the mixture at 600 ℃ (temperature rise rate of 5 ℃/min) for 2h to obtain NiO, CuO and PtO₂、Fe₂O₃And Co₃O₄Mixing; after keeping for 0.5h in a nitrogen atmosphere, NiO, CuO and PtO are treated in a hydrogen atmosphere at a temperature of 400 DEG C₂、Fe₂O₃And Co₃O₄The mixture was reduced for 1.5h,and cooling the alloy in a furnace to room temperature to obtain FeCoNiCuPt nano high-entropy alloy powder (marked as FeCoNiCuPt-1), and placing the FeCoNiCuPt nano high-entropy alloy powder in an inert atmosphere for storage.

XRD phase analysis is carried out on FeCoNiCuPt-1 high-entropy alloy powder, and the result is shown in figure 2. Wherein, FIG. 2 shows the X-ray diffraction pattern of FeCoNiCuPt-1 nanometer high-entropy alloy powder.

As can be seen from FIG. 2, the FeCoNiCuPt-1 high-entropy alloy powder has only one phase, and no peaks of the individual elements Fe, Co, Ni, Cu and Pt are observed, and the peaks of the FeCoNiCuPt-1 high-entropy alloy powder are significantly shifted and broadened relative to the peaks of the individual elements, which indicates that Fe, Co, Ni, Cu and Pt form a high-entropy alloy and have lattice distortion. In addition, the particle size of the FeCoNiCuPt-1 high-entropy alloy powder is about 70nm according to the half-peak estimation of the grain size.

The FeCoNiCuPt-1 high-entropy alloy powder is characterized by a scanning electron microscope and a transmission electron microscope, and the results are shown in FIGS. 3 to 4. FIG. 3 is a scanning electron microscope image of FeCoNiCuPt-1 high-entropy alloy powder; FIG. 4 is a transmission electron microscope image of FeCoNiCuPt-1 high entropy alloy powder.

As can be seen from FIGS. 3 and 4, the FeCoNiCuPt-1 high-entropy alloy powder has uniform particle distribution and particle size of about 80nm, which is substantially consistent with the XRD analysis result.

Comparative example 1

This comparative example 1 provides a method for preparing FeCoNiCuPt nano high-entropy alloy powder, which includes the following steps:

taking the molar ratio of the transition metal elements as 1:1:1:1:1, weighing the transition metal salt precursor according to the dosage of 0.3mmol of each transition metal element, and concretely, 72.76mg NiCl₂•6H₂O、59.88mgFeCl₂•4H₂O、51.68mgCuCl₂•2H₂O、71.12mgCoCl₂•6H₂O、3mL(0.1M)H₂PtCl₆•6H₂Adding O into 40mL of ethanol solvent, stirring and dissolving in a constant-temperature water bath at 60 ℃, and then performing ultrasonic dispersion for 10min to obtain a blending solution;

dropwise adding the blending solution in a constant-temperature water bath at 60 ℃ and stirringAdding 10mL (1M) of NaOH solution, and continuing stirring for 2h to ensure that the transition metal salt precursor is subjected to coprecipitation reaction to completely generate Fe (OH)₂、Ni(OH)₂、Co(OH)₂、Cu(OH)₂And Pt (OH)₄Precipitating the mixture;

transferring the reaction system of the transition metal salt precursor into a hydrothermal kettle at 80 ℃ for aging for 12h, and then separating out the generated Fe (OH)₂、Ni(OH)₂、Co(OH)₂、Cu(OH)₂And Pt (OH)₄Precipitating the mixture and adding Fe (OH)₂、Ni(OH)₂、Co(OH)₂、Cu(OH)₂And Pt (OH)₄Washing the precipitate mixture with water and ethanol for three times, and vacuum drying for 12h to obtain Fe (OH)₂、Ni(OH)₂、Co(OH)₂、Cu(OH)₂And Pt (OH)₄Mixing;

in an air atmosphere, Fe (OH)₂、Ni(OH)₂、Co(OH)₂、Cu(OH)₂And Pt (OH)₄Calcining the mixture at 600 ℃ (temperature rise rate of 5 ℃/min) for 2h to obtain NiO, CuO and PtO₂、Fe₂O₃And Co₃O₄Mixing; after keeping for 0.5h in a nitrogen atmosphere, NiO, CuO and PtO are treated in a hydrogen atmosphere at a temperature of 400 DEG C₂、Fe₂O₃And Co₃O₄And reducing the mixture for 1.5h, cooling the mixture in a furnace to room temperature to obtain FeCoNiCuPt nano high-entropy alloy powder (marked as FeCoNiCuPt-2), and placing the FeCoNiCuPt nano high-entropy alloy powder in an inert atmosphere for storage.

XRD phase analysis was performed on FeCoNiCuPt-2 high entropy alloy powder, and the result is shown in FIG. 5. Wherein, FIG. 5 shows the X-ray diffraction pattern of FeCoNiCuPt-2 high-entropy alloy powder.

As can be seen from FIG. 5, the FeCoNiCuPt-2 high-entropy alloy powder has only one phase, the peak has higher intensity than that of the peak in FIG. 1, the peaks of the single elements Fe, Co, Ni, Cu and Pt are not observed, and the peaks of the FeCoNiCuPt-2 high-entropy alloy powder are obviously shifted and broadened relative to the peaks of the single elements, which indicates that Fe, Co, Ni, Cu and Pt form a high-entropy alloy and have lattice distortion. In addition, the particle size of the FeCoNiCuPt-2 high-entropy alloy powder is about 150nm according to the half-peak estimation of the grain size.

The FeCoNiCuPt-2 high-entropy alloy powder is characterized by a scanning electron microscope and a transmission electron microscope, and the results are shown in FIGS. 6 to 7. FIG. 6 is a scanning electron microscope image of FeCoNiCuPt-2 high-entropy alloy powder; FIG. 7 is a transmission electron microscope image of FeCoNiCuPt-2 high entropy alloy powder.

As can be seen from FIGS. 6 and 7, the FeCoNiCuPt-2 high-entropy alloy powder has uniform particle distribution and particle size of about 160nm, which is substantially consistent with the XRD analysis result.

Comparing the characterization results of example 1 and comparative example 1, it can be seen that, before the ultrasonic dispersion is performed on the transition metal salt precursor solution, polyvinylpyrrolidone and activated carbon are added to the transition metal salt precursor solution to prepare FeCoNiCuPt nano high-entropy alloy powder with smaller particle size.

Example 2

Theembodiment 2 provides a preparation method of FeCoNiCuCrPt nano high-entropy alloy powder, which includes the following steps:

taking the molar ratio of the transition metal elements as 1:1:1:1:1:1, weighing the transition metal salt precursor according to the dosage of 0.3mmol of each transition metal element, and concretely, 72.76mg NiCl₂•6H₂O、59.88mgFeCl₂•4H₂O、51.68mgCuCl₂•2H₂O、71.12mgCoCl₂•6H₂O、83.27mgCrCl₃•6H₂O、3mL(0.1M)H₂PtCl₆•6H₂Adding O and 90mg of polyvinylpyrrolidone into 50mL of ethanol solvent, stirring and dissolving in a constant-temperature water bath at 60 ℃, adding 20mg of activated carbon, and performing ultrasonic dispersion for 10min to obtain a blending solution;

dropwise adding 15mL (1M) of NaOH solution into the blending solution in a thermostatic water bath at 60 ℃ and stirring, and continuously stirring for 2h to ensure that the transition metal salt precursor is subjected to coprecipitation reaction to completely generate Fe (OH)₂、Ni(OH)₂、Co(OH)₂、Cu(OH)₂、Cr(OH)₃And Pt (OH)₄Precipitating the mixture;

transferring the reaction system of the transition metal salt precursor into a hydrothermal kettle at 80 ℃ for aging for 12h, and then separating out the generated Fe (OH)₂、Ni(OH)₂、Co(OH)₂、Cu(OH)₂、Cr(OH)₃And Pt (OH)₄Precipitating the mixture and adding Fe (OH)₂、Ni(OH)₂、Co(OH)₂、Cu(OH)₂、Cr(OH)₃And Pt (OH)₄Washing the precipitate mixture with water and ethanol for three times, and vacuum drying for 12h to obtain Fe (OH)₂、Ni(OH)₂、Co(OH)₂、Cu(OH)₂、Cr(OH)₃And Pt (OH)₄Mixing;

in an air atmosphere, Fe (OH)₂、Ni(OH)₂、Co(OH)₂、Cu(OH)₂、Cr(OH)₃And Pt (OH)₄Calcining the mixture at 600 ℃ (temperature rise rate of 5 ℃/min) for 2h to obtain NiO, CuO and PtO₂、Fe₂O₃、Cr₂O₃And Co₃O₄Mixing; after keeping for 0.5h in a nitrogen atmosphere, NiO, CuO and PtO are treated in a hydrogen atmosphere at a temperature of 400 DEG C₂、Fe₂O₃、Cr₂O₃And Co₃O₄And reducing the mixture for 1.5h, cooling the mixture in a furnace to room temperature to obtain FeCoNiCuCrPt nano high-entropy alloy powder, and placing the FeCoNiCuCrPt nano high-entropy alloy powder in an inert atmosphere for preservation.

Example 3

This embodiment 3 provides a method for preparing agapptcutpd nano high-entropy alloy powder, which includes the following steps:

taking the molar ratio of the transition metal elements as 1:1:1:1:1, weighing the transition metal salt precursor according to the dosage of 0.3mmol of each transition metal element, and concretely, 51.48mg AgNO₃、3mL(0.1M) H₂PtCl₆•6H₂O、3mL(0.1M) HAuCl₄、51.68mg CuCl₂•2H₂O、83.27mgCrCl₃•6H₂O、89.15mg Na₂PdCl₄And 90mg of polyvinylpyrrolidone into 50mL of ethanol solvent, stirring and dissolving in a constant-temperature water bath at 60 ℃, and then adding 20mg of polyvinylpyrrolidonePerforming ultrasonic dispersion on the charcoal for 10min to obtain a blending solution;

dropwise adding 20mL (1M) of NaOH solution into the blending solution in a constant-temperature water bath at 60 ℃ and stirring, and continuously stirring for 2h to ensure that the transition metal salt precursor is subjected to coprecipitation reaction to completely generate AgOH, HAuO and Cu (OH)₂、Pb(OH)₂And Pt (OH)₄Precipitating the mixture;

transferring the reaction system of the transition metal salt precursor into a hydrothermal kettle at 80 ℃ for aging for 12h, and then separating the generated AgOH, HAuO and Cu (OH)₂、Pb(OH)₂And Pt (OH)₄Precipitating the mixture, and adding AgOH, HAuO, Cu (OH)₂、Pb(OH)₂And Pt (OH)₄Washing the precipitate mixture with water and ethanol for three times, and vacuum drying for 12 hr to obtain AgOH, HAuO, Cu (OH)₂、Pb(OH)₂And Pt (OH)₄Mixing;

in an air atmosphere, Ag₂O、Au₂O₃CuO, PbO and PtO₂Calcining the mixture at 600 deg.C (temperature rise rate of 5 deg.C/min) for 2 hr to obtain Ag₂O、Au₂O₃CuO, PbO and PtO₂Mixing; after keeping for 0.5h in nitrogen atmosphere, Ag was treated in hydrogen atmosphere at 400 deg.C₂O、Au₂O₃CuO, PbO and PtO₂And reducing the mixture for 1.5h, cooling the mixture in a furnace to room temperature to obtain AgAuPtCuPd nano high-entropy alloy powder, and placing the AgAuPtCuPd nano high-entropy alloy powder in an inert atmosphere for storage.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims (10)

Translated fromChinese

1.一种纳米高熵合金粉末的制备方法，其特征在于，包括：1. a preparation method of nanometer high-entropy alloy powder, is characterized in that, comprises:将五种以上的过渡金属盐前驱体溶解于同一溶剂中，并在溶解之后进行超声分散，得到共混溶液，其中，所述过渡金属盐前驱体中的过渡金属生成的过渡金属氧化物能够被氢气和/或一氧化碳还原；More than five transition metal salt precursors are dissolved in the same solvent, and ultrasonic dispersion is performed after dissolving to obtain a blended solution, wherein the transition metal oxide generated by the transition metal in the transition metal salt precursor can be hydrogen and/or carbon monoxide reduction;对所述共混溶液加入强碱溶液并充分搅拌，以使所述过渡金属盐前驱体进行共沉淀反应完全生成过渡金属氢氧化物沉淀混合物；adding a strong base solution to the blended solution and fully stirring, so that the transition metal salt precursor undergoes a co-precipitation reaction to completely generate a transition metal hydroxide precipitation mixture;将所述过渡金属盐前驱体的反应体系在60-180℃的温度下陈化6-48h，然后分离出生成的过渡金属氢氧化物沉淀混合物，并对所述过渡金属氢氧化物沉淀混合物依次进行水洗、醇洗、干燥处理，得到过渡金属氢氧化物混合物；The reaction system of the transition metal salt precursor is aged at a temperature of 60-180 ° C for 6-48 hours, and then the resulting transition metal hydroxide precipitation mixture is separated, and the transition metal hydroxide precipitation mixture is sequentially Carry out water washing, alcohol washing and drying to obtain a transition metal hydroxide mixture;在400-800℃的温度以及空气气氛中，对所述过渡金属氢氧化物混合物进行煅烧2-10h，得到过渡金属氧化物；然后在300-600℃的温度以及氢气和/或一氧化碳气氛中，对所述过渡金属氧化物进行还原反应1-2h，即得纳米高熵合金粉末。The transition metal hydroxide mixture is calcined for 2-10 hours at a temperature of 400-800°C and in an air atmosphere to obtain a transition metal oxide; then at a temperature of 300-600°C and in an atmosphere of hydrogen and/or carbon monoxide, The reduction reaction of the transition metal oxide is carried out for 1-2 hours to obtain nanometer high-entropy alloy powder.2.根据权利要求1所述的纳米高熵合金粉末的制备方法，其特征在于，对过渡金属盐前驱体溶解液进行超声分散之前，还包括在所述过渡金属盐前驱体溶解液中加入聚乙烯吡咯烷酮和活性炭。2. the preparation method of nanometer high-entropy alloy powder according to claim 1, is characterized in that, before carrying out ultrasonic dispersion to transition metal salt precursor dissolved liquid, also comprises adding polymer in described transition metal salt precursor dissolved liquid Vinylpyrrolidone and activated carbon.3.根据权利要求1或2所述的纳米高熵合金粉末的制备方法，其特征在于，所述过渡金属盐前驱体进行共沉淀反应是在40-80℃的温度下进行，所述共沉淀反应的时间为0.5-2.5h。3. The preparation method of nanometer high-entropy alloy powder according to claim 1 or 2, wherein the co-precipitation reaction of the transition metal salt precursor is carried out at a temperature of 40-80° C. The reaction time is 0.5-2.5h.4.根据权利要求1或2所述的纳米高熵合金粉末的制备方法，其特征在于，所述过渡金属盐前驱体包括过渡金属硝酸盐、过渡金属硫酸盐以及过渡金属氯化物中的任一种。4. the preparation method of nanometer high-entropy alloy powder according to claim 1 and 2, is characterized in that, described transition metal salt precursor comprises any in transition metal nitrate, transition metal sulfate and transition metal chloride kind.5.根据权利要求4所述的纳米高熵合金粉末的制备方法，其特征在于，所述溶剂包括甲醇、乙醇或者去离子水中的任一种。5 . The method for preparing nanometer high-entropy alloy powder according to claim 4 , wherein the solvent comprises any one of methanol, ethanol or deionized water. 6 .6.根据权利要求5所述的纳米高熵合金粉末的制备方法，其特征在于，所述强碱溶液包括氢氧化钠溶液、氢氧化钾溶液中的任一种。6 . The method for preparing nanometer high-entropy alloy powder according to claim 5 , wherein the strong alkali solution comprises any one of sodium hydroxide solution and potassium hydroxide solution. 7 .7.根据权利要求4所述的纳米高熵合金粉末的制备方法，其特征在于，所述过渡金属盐前驱体包括NiCl₂·6H₂O、FeCl₂·4H₂O、CuCl₂•2H₂O、CoCl₂·6H₂O和H₂PtCl₆·6H₂O。7 . The method for preparing nanometer high-entropy alloy powder according to claim 4 , wherein the transition metal salt precursor comprises NiCl₂ .6H₂ O, FeCl₂ .4H₂ O, and CuCl₂ .2H₂ O. 8 . , CoCl₂ ·6H₂ O, and H₂ PtCl₆ ·6H₂ O.8.根据权利要求7所述的纳米高熵合金粉末的制备方法，其特征在于，所述过渡金属盐前驱体还包括CrCl₃·6H₂O。8 . The method for preparing nanometer high-entropy alloy powder according to claim 7 , wherein the transition metal salt precursor further comprises CrCl₃ ·6H₂ O. 9 .9.根据权利要求7或8所述的纳米高熵合金粉末的制备方法，其特征在于，所述纳米高熵合金粉末保存在惰性气体气氛中。9 . The method for preparing nanometer high-entropy alloy powder according to claim 7 or 8 , wherein the nanometer high-entropy alloy powder is stored in an inert gas atmosphere. 10 .10.根据权利要求4所述的纳米高熵合金粉末的制备方法，其特征在于，所述过渡金属盐前驱体包括AgNO₃、H₂PtCl₆·6H₂O、HAuCl₄、CuCl₂•2H₂O和Na₂PdCl₄。10 . The method for preparing nanometer high-entropy alloy powder according to claim 4 , wherein the transition metal salt precursor comprises AgNO₃ , H₂ PtCl₆ ·6H₂ O, HAuCl₄ , CuCl₂ ·2H₂ . 10 . O and Na₂ PdCl₄ .

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