阅读说明：本技术 高熵合金及其制备、包括该合金的涂层及制备 (High-entropy alloy and preparation thereof, coating comprising alloy and preparation ) 是由 杨潇 杨增朝 贺刚 李永 李江涛 王文瑞 祁武 谢璐 于 2019-02-21 设计创作，主要内容包括：本发明公开一种高熵合金,以原子百分含量计,其原料包括如下组成：Co：22.5-25％,Cr：22.5-25％,Fe：22.5-25％,Ni：22.5-25％,Nb：0-10％。该合金具有高熵,且适于制备结构致密、均匀且具有高的硬度,高强度,高韧性,高耐磨性以及好的耐腐蚀性能的涂层。本发明还公开了该高熵合金的制备方法以及包含该高熵合金的涂层及制备方法。(The invention discloses a high-entropy alloy which comprises the following raw materials in atomic percentage: co: 22.5-25%, Cr: 22.5-25%, Fe: 22.5-25%, Ni: 22.5-25%, Nb: 0 to 10 percent. The alloy has high entropy and is suitable for preparing a coating which has a compact and uniform structure, high hardness, high strength, high toughness, high wear resistance and good corrosion resistance. The invention also discloses a preparation method of the high-entropy alloy, a coating containing the high-entropy alloy and a preparation method of the coating.)

1. The high-entropy alloy is characterized by comprising the following raw materials in atomic percentage: co: 22.5-25%, Cr: 22.5-25%, Fe: 22.5-25%, Ni: 22.5-25%, Nb: 0 to 10 percent.

2. A high entropy alloy as claimed in claim 1, wherein the grain size of the alloy is in the range 30 μm to 50 μm.

3. A high entropy alloy as claimed in claim 1, wherein the purity of each of Co, Cr, Fe, Ni and Nb is 99.99% or more.

4. A method for producing a high entropy alloy as claimed in claim 1, characterized by comprising the steps of:

metal simple substances of Co, Cr, Fe, Ni and Nb are mixed according to the atomic percentage content of Co: 22.5-25%, Cr: 22.5-25%, Fe: 22.5-25%, Ni: 22.5-25%, Nb: mixing 0-10% of the ingredients, and melting in vacuum to obtain an alloy melt;

and atomizing the alloy melt into liquid drops, and solidifying into particles to obtain the powder-shaped high-entropy alloy.

5. The preparation method according to claim 4, wherein the step of atomizing the alloy melt into droplets by the mist and then solidifying the droplets into granules comprises the following steps: under the protection of mixed gas formed by inert gas and reducing gas, atomizing the alloy melt into liquid drops in high-pressure gas flow formed by the mixed gas, and then solidifying into particles.

6. The method of claim 5, wherein the inert gas is selected from argon or helium; the reducing gas is selected from hydrogen.

7. A high entropy alloy wear and corrosion resistant coating, characterized in that the raw material of the coating comprises the high entropy alloy of claim 1.

8. A high entropy alloy wear and corrosion resistant coating as claimed in claim 7, wherein the thickness of the high entropy alloy wear and corrosion resistant coating is 200 μm-500 μm.

9. The preparation method of the high-entropy alloy wear-resistant and corrosion-resistant coating of claim 7, which is characterized by comprising the step of spraying the high-entropy alloy in powder form on a substrate to be sprayed by means of plasma spraying to form the high-entropy alloy wear-resistant and corrosion-resistant coating.

10. The production method according to claim 9,

the material of the substrate is selected from one or more of low-carbon steel, medium-carbon steel, high-carbon steel, titanium alloy or aluminum alloy;

preferably, the process parameters of the plasma spraying are as follows: the spraying distance is 80-130mm, the arc current is 300-500A, the moving speed of the spraying gun is as follows: 30-80mm/s, Ar gas flow of 80L/min, H₂The air flow is 5-10L/min.

Technical Field

The invention relates to the technical field of plasma spraying. And more particularly, to a high-entropy alloy and preparation thereof, a coating including the alloy and preparation thereof.

Background

The high-entropy alloy generally has four or more main elements, and is a novel multi-element alloy with the mixed entropy higher than the melting entropy. High entropy alloys have some special properties: 1) the high entropy effect is realized, the mixing entropy of the alloy is obviously higher than that of the traditional metal alloy, and a simple solid solution structure is easy to form; 2) lattice distortion effect, which is caused by the difference of atomic radius between elements, thereby affecting the mechanical and physical properties of the material; 3) the delayed diffusion effect is realized, even if the effective diffusion among elements in the high-entropy alloy is limited by serious lattices, the high-temperature structure of the alloy is easy to stabilize; 4) the cocktail effect, also known as the collective effect between elements, makes the material exhibit an excellent combination of properties.

The CoCrFeNi series high-entropy alloy has the advantages of high thermal stability, high toughness, excellent corrosion resistance and the like, and has wide application prospects in the fields of aerospace, mechanical manufacturing, chemical engineering, electronics, national defense and military and the like. However, the strength of the material is low, and trace Nb element is often added into the CoCrFeNi high-entropy alloy for the purpose of mechanical property, so that Laves strengthening phases such as Co2Nb, Ni2Nb, Fe2Nb and Cr2Nb are formed, and the comprehensive property of the material is improved. Research shows that the Co-Cr-Fe-Ni-Nb high-entropy alloy has high strength and high toughness and is an excellent engineering structure material. However, the cost of this material is high, limiting its practical application.

When the high-entropy alloy coating is prepared by using the traditional method, the high-entropy alloy coating is prepared by adopting a vacuum magnetron sputtering method, a thermal evaporation deposition method, a laser cladding method, an induction heating cladding method, a laser 3D printing method and other methods because the melting point of the high-entropy alloy is higher. The traditional preparation methods generally adopt high-purity alloy target materials, mixed simple substance metal powder or mechanical alloying powder as coating preparation raw materials, but alloying elements are obviously segregated in the preparation process.

Therefore, it is necessary to provide a new technical solution to solve the existing technical problems.

Disclosure of Invention

The first object of the present invention is to provide a high entropy alloy which has a high entropy and is suitable for the preparation of coatings which are structurally compact, homogeneous and have a high hardness, a high strength, a high toughness, a high wear resistance and a good corrosion resistance.

The second purpose of the invention is to provide a preparation method of the high-entropy alloy.

The third purpose of the invention is to provide a high-entropy alloy wear-resistant and corrosion-resistant coating which has high hardness.

The fourth purpose of the invention is to provide a preparation method of the high-entropy alloy wear-resistant corrosion-resistant coating, and the coating prepared by the method has a compact and uniform structure, high hardness and good corrosion resistance.

In order to achieve the first object, the invention provides a high-entropy alloy, which comprises the following raw materials in atomic percentage: co: 22.5-25%, Cr: 22.5-25%, Fe: 22.5-25%, Ni: 22.5-25%, Nb: 0 to 10 percent.

Preferably, the purities of the Co, the Cr, the Fe, the Ni and the Nb are all more than 99.99%.

Preferably, the alloy has a particle size of 30 to 50 μm.

Preferably, the atomic percentage of Nb in the raw material is 2-10%.

The addition amount of each component in the raw materials of the alloy provided in the first object of the invention has a great influence on the performance of the alloy, and the components are strictly controlled within the limited range so as to be suitable for preparing a coating with compact and uniform structure, high hardness and good corrosion resistance.

In order to achieve the second object, the invention provides a preparation method of a high-entropy alloy, which comprises the following steps:

metal simple substances of Co, Cr, Fe, Ni and Nb are mixed according to the atomic percentage content of Co: 22.5-25%, Cr: 22.5-25%, Fe: 22.5-25%, Ni: 22.5-25%, Nb: mixing 0-10% of the ingredients, and melting in vacuum to obtain an alloy melt;

and atomizing the alloy melt into liquid drops, and solidifying into particles to obtain the powder-shaped high-entropy alloy.

Preferably, the mode that the alloy melt is atomized into liquid drops by the fog and then solidified into particles comprises the following steps: under the protection of mixed gas formed by inert gas and reducing gas, atomizing the alloy melt into liquid drops in high-pressure gas flow formed by the mixed gas, and then solidifying into particles.

By adopting the technical scheme, the precise control of each component is facilitated, and the prepared high-entropy alloy powder is uniform in granularity and stable in structure.

In the above technical solution of the present invention, the alloy melt may be atomized into droplets in a high pressure gas flow formed by the mixed gas, preferably by spraying, and then spontaneously solidified into particles in the falling process of the droplets.

In some preferred forms, the inert gas includes: argon, helium. The use of inert gas reduces oxidation of the feedstock.

In some preferred forms, the reducing gas includes: hydrogen gas.

In order to achieve the third object, the invention provides a high-entropy alloy wear-resistant corrosion-resistant coating, and the raw material of the coating comprises the high-entropy alloy provided by the first object.

Preferably, the thickness of the high-entropy alloy wear-resistant and corrosion-resistant coating is 200-500 μm.

In order to achieve the fourth purpose, the invention provides a preparation method of the high-entropy alloy wear-resistant corrosion-resistant coating, which comprises the step of spraying the high-entropy alloy in powder form on a substrate to be sprayed by adopting a plasma spraying mode to form the high-entropy alloy wear-resistant corrosion-resistant coating.

Preferably, the material of the substrate is an alloy material.

More preferably, the alloy material is one or more of low-carbon steel, medium-carbon steel, high-carbon steel, titanium alloy or aluminum alloy.

Preferably, the high-entropy alloy wear-resistant and corrosion-resistant coating is distributed on the substrate in a dispersion manner.

Preferably, the process parameters of the plasma spraying are as follows: the spraying distance is 80-130mm, the arc current is 300-500A, the moving speed of the spraying gun is as follows: 30-80mm/s, Ar gas flow of 80L/min, H₂The air flow is 5-10L/min. Under the condition, the high-entropy alloy can be completely melted in the plasma spraying process, the sintering phenomenon is avoided, and meanwhile, the size of the internal gap of the plasma spraying is reasonable, so that the mechanical property, the wear resistance and the corrosion resistance of the prepared coating are better.

The invention has the following beneficial effects:

the high-entropy alloy provided by the invention strictly limits the content of each component, so that the alloy has high entropy, and is suitable for preparing a coating which has a compact and uniform structure, high hardness, high strength, high toughness, high wear resistance and good corrosion resistance.

The alloy coating provided by the invention has the microstructure characteristic that the Laves strengthening phase is dispersed and distributed on a face-centered cubic (FCC) structure high-entropy alloy matrix, and has the characteristics of high strength, high toughness, high wear resistance, high corrosion resistance and the like. The alloy coating is coated on a substrate to be coated, and the problem of high cost caused by directly using the high-entropy alloy as an engineering structure material in the prior art is solved.

Compared with the traditional method for preparing the high-entropy alloy coating by hot-pressing sintering, laser cladding or magnetron sputtering and the like, the method for preparing the high-entropy alloy wear-resistant and corrosion-resistant coating by the plasma spraying method has the characteristics of good compactness, high bonding strength, simple preparation method and the like, and simultaneously avoids the problem that the components and the structure of the coating deviate from the design obviously.

Drawings

The following describes embodiments of the present invention in further detail with reference to the accompanying drawings.

FIG. 1 shows Co of example 2 of the present invention₂₄Cr₂₄Fe₂₄Ni₂₄Nb₄High-entropy alloy wear-resistant corrosion-resistantXRD pattern of the coating.

FIG. 2 shows Co of example 2 of the present invention₂₄Cr₂₄Fe₂₄Ni₂₄Nb₄SEM image of the high-entropy alloy wear-resistant corrosion-resistant coating.

Detailed Description

In order to more clearly illustrate the invention, the invention is further described below with reference to preferred embodiments and the accompanying drawings. Similar parts in the figures are denoted by the same reference numerals. It is to be understood by persons skilled in the art that the following detailed description is illustrative and not restrictive, and is not to be taken as limiting the scope of the invention.