A MSi2 type high entropy silicide powder and its preparation method and application

Abstract

The present invention discloses a M Si2 type high entropy silicide powder and its preparation method and application. According to mass fraction, 30-50% high entropy alloy powder, 10-30% silicon powder, 2-10% catalyst and 30-50% inert filler are mixed by a mixer to obtain a mixed powder; the high entropy alloy powder includes at least three metal elements of Ta, W, Nb, Mo, V, Zr, Hf, Ti and Cr, wherein the particle size of the high entropy alloy powder is 20-200 μm; the particle size of the silicon powder and the inert filler is not more than 10 μm; the mixed powder is sintered at a medium-high temperature of 1050-1200 °C for 12-20h under an inert gas atmosphere to make the high entropy alloy powder react in situ to generate high entropy silicide powder; the high entropy silicide powder is vibrated and sieved to separate M Si2 type high entropy silicide powder. The preparation method of the present invention has high adjustability for component design, and the obtained high entropy silicide powder has high purity, uniform structure, and uniform element distribution. The coating prepared by using it has good high temperature oxidation resistance and broad application prospects.

Description

Technical Field

[0001] The present invention discloses a M Si 2 The invention discloses a high entropy silicide powder and a preparation method and application thereof, belonging to the field of ultra-high temperature material preparation. Background Art

[0002] Whether in the defense or civilian fields, high-temperature structural materials have always occupied an important position in hot-end components and are considered to be the key to leading the development of the industry. For example, high-temperature alloys, refractory metal-based alloys, carbon / carbon composite materials, etc. are widely used in hot-end components. However, the above materials all have the problem of insufficient antioxidant performance, and an antioxidant coating must be prepared on the surface when they are actually in service.

[0003] Refractory metal silicides, such as MoSi 2 、TaSi 2 , WSi 2 It has a high melting point and generates SiO 2 The protective oxide film mainly composed of metal oxides has become a research hotspot for anti-oxidation coating materials. However, the anti-oxidation ability of single metal silicide coatings is insufficient, and generally requires the addition of active elements for modification or the addition of a second phase. In recent years, high entropy silicides have shown mechanical properties and strong anti-oxidation properties that exceed those of single metal silicides due to their unique "high entropy effect", and are expected to become a new research hotspot for anti-oxidation coatings.

[0004] Powder materials, especially high-quality powders with high adjustability in component design, uniform composition and high purity, are in great demand and have good application prospects in advanced powder metallurgy, thermal spraying, 3D printing and other technical fields. However, the existing reports on the preparation of high-entropy powders are mostly focused on the preparation of high-entropy alloy powders, high-entropy boride powders, high-entropy oxide powders and high-entropy carbide powders, while the preparation of high-entropy silicide powders is rarely reported and disclosed.

[0005] In the prior art, M Si 2 The common synthesis method of high entropy silicide is to mix disilicide powders of multiple single metals in a certain proportion and then sinter them at high temperature and high pressure. This method has certain limitations on the selection of silicide components in order to achieve high entropy. Summary of the invention

[0006] For the preparation of the prior art M Si 2 The present invention provides a method for solving the problem that the type high entropy silicide has certain limitations on the selection of silicide components. M Si 2The invention discloses a high-entropy silicide powder and a preparation method and application thereof. The method of the invention has high adjustability for component design, and the obtained high-entropy silicide powder has high purity, uniform structure, and uniform element distribution. The coating prepared by using the high-entropy silicide powder has good high-temperature oxidation resistance and broad application prospects.

[0007] In order to solve the problems of the prior art, the technical solution adopted by the present invention is:

[0008] A sort of M Si 2 A method for preparing high entropy silicide powder comprises the following steps:

[0009] (1) By mass fraction, 30-50% high entropy alloy powder, 10-30% silicon powder, 2-10% infiltration catalyst and 30-50% inert filler are mixed by a mixer to obtain a mixed powder; the high entropy alloy powder comprises at least three metal elements of Ta, W, Nb, Mo, V, Zr, Hf, Ti and Cr, wherein the particle size of the high entropy alloy powder is 20-200 μm; the particle size of the silicon powder and the inert filler is not greater than 10 μm;

[0010] (2) Sintering the mixed powder at a medium-high temperature of 1050-1200°C for 12-20 hours under an inert gas atmosphere to allow the high entropy alloy powder to react in situ to generate high entropy silicide powder;

[0011] (3) Vibrate and sieve the high entropy silicide powder to separate M Si 2 Type high entropy silicide powder.

[0012] As an improvement, in step (1), the high entropy alloy powder includes at least three metal elements of Ta, W, Nb, Mo, V, Zr, Hf, Ti, and Cr, and the molar percentage content of each metal element is 15-40%.

[0013] As an improvement, in step (1), the catalyst is NaF or NH 4 One or a combination of two of F.

[0014] As an improvement, in step (1), the inert filler is at least Al 2 O 3 、SiO 2 Or one of SiC.

[0015] As an improvement, in step (1), the high entropy alloy powder is prepared by atomization, mechanical crushing after vacuum smelting, mechanical alloying, spray granulation or plasma spheroidization.

[0016] The obtained product is prepared based on the above preparation method. M Si 2Type high entropy silicide powder, wherein the particle size is 20~200 μm, the elements are evenly distributed, and in terms of atomic percentage, Si atoms account for 60~70% and metal elements account for 30~40%.

[0017] The obtained product is prepared based on the above preparation method. M Si 2 Application of high entropy silicide powder in preparing oxidation-resistant coatings on refractory alloys or carbon / carbon composites.

[0018] As an improvement, the method for preparing the anti-oxidation coating is thermal spraying, laser cladding, slurry sintering, hot pressing sintering or spark plasma sintering. Beneficial Effects

[0019] Compared with the prior art, the present invention provides a M Si 2 The invention relates to a type of high entropy silicide powder and its preparation method and application. It creatively proposes to use high entropy alloy powder as raw material, adopt solid powder siliconization process to react high entropy alloy powder in situ to generate high entropy silicide powder, and use the difference in particle size between high entropy silicide powder and inert filler to perform vibration screening, and separate high entropy silicide powder, so as to obtain a set of components with high adjustability, high purity, uniform organization, controllable particle size, uniform element distribution, which can be suitable for the use requirements of powder metallurgy, thermal spraying, and 3D printing, and the coating obtained has the advantages of good high temperature oxidation resistance, etc. M Si 2 Type high entropy silicide powder. Specifically:

[0020] (1) Compared with the prior art method of mixing multiple single metal disilicide powders or multiple elemental metal powders with silicon powder in a certain proportion and then sintering at high temperature and high pressure, the M Si 2 For high-entropy silicide, the present invention uses a solid powder siliconizing process to react the high-entropy alloy powder in situ to generate high-entropy silicide powder, and then uses the difference in powder particle size to perform vibration screening to obtain high-purity high-entropy silicide powder. On the first aspect, the method of the present invention has no restrictions on the components of the high-entropy alloy, and the component design has high adjustability; on the second aspect, no high-pressure conditions are required during the synthesis process, and the synthesis temperature is low, which reduces the requirements for synthesis equipment; on the third aspect, the high-entropy silicide powder prepared by the present invention has not changed in morphology compared to the raw material high-entropy alloy powder, and is applicable to high-entropy alloy powders prepared by different preparation methods (such as atomization powder making, vacuum melting followed by mechanical crushing powder making, mechanical alloying powder making, spray granulation powder making, or plasma spheroidization powder making, etc.), and has a wide range of applications;

[0021] (2) The method for preparing high entropy silicide powder proposed in the present invention has a simple process. After the synthesis is completed, the silicon powder and inert filler obtained by vibration screening and separation can be re-prepared and reused. The synthesis cost is low and it is suitable for large-scale industrial production.

[0022] (3) The high entropy silicide powder prepared by the present invention can be coated on the surface of high-temperature components such as refractory alloys and carbon / carbon composite materials through processes such as thermal spraying, laser cladding, slurry sintering, hot pressing sintering or spark plasma sintering to prepare an antioxidant coating, thereby providing antioxidant protection for high-temperature components. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 (Nb, Mo, Ta, W)Si prepared in Example 1 2 Cross-sectional EDS composition distribution of high entropy silicide powder. DETAILED DESCRIPTION

[0024] A sort of M Si 2 A method for preparing high entropy silicide powder comprises the following steps:

[0025] (1) By mass fraction, 30-50% high entropy alloy powder, 10-30% silicon powder, 2-10% infiltration catalyst and 30-50% inert filler are mixed by a mixer to obtain a mixed powder; the high entropy alloy powder comprises at least three metal elements of Ta, W, Nb, Mo, V, Zr, Hf, Ti and Cr, wherein the particle size of the high entropy alloy powder is 20-200 μm; the particle size of the silicon powder and the inert filler is not greater than 10 μm;

[0026] (2) Sintering the mixed powder at a medium-high temperature of 1050-1200°C for 12-20 hours under an inert gas atmosphere to allow the high entropy alloy powder to react in situ to generate high entropy silicide powder;

[0027] (3) Vibrate and sieve the high entropy silicide powder to separate M Si 2 Type high entropy silicide powder.

[0028] Specifically, in step (1), the high entropy alloy powder includes at least three metal elements of Ta, W, Nb, Mo, V, Zr, Hf, Ti, and Cr, and the molar percentage content of each metal element is 15-40%.

[0029] In step (1), the catalyst is NaF or NH 4 One or a combination of two of F.

[0030] In step (1), the inert filler is at least Al 2 O 3 、SiO2 Or one of SiC.

[0031] In step (1), the high entropy alloy powder is prepared by atomization, mechanical crushing after vacuum smelting, mechanical alloying, spray granulation or plasma spheroidization.

[0032] The obtained product is prepared based on the above preparation method. M Si 2 Type high entropy silicide powder, wherein the particle size is 20~200 μm, the elements are evenly distributed, and in terms of atomic percentage, Si atoms account for 60~70% and metal elements account for 30~40%.

[0033] The obtained product is prepared based on the above preparation method. M Si 2 Application of high entropy silicide powder in preparing oxidation-resistant coatings on refractory alloys or carbon / carbon composites.

[0034] The method for preparing the anti-oxidation coating is thermal spraying, plasma spraying, laser cladding or slurry sintering.

[0035] Example 1 (Nb, Mo, Ta, W)Si 2 Preparation of high entropy silicide powder

[0036] A (Nb,Mo,Ta,W)Si 2 The method for preparing high entropy silicide powder comprises the following steps:

[0037] (1) Mix NbMoTaW high entropy alloy powder, silicon powder, and catalyst (NH 4 F) and inert filler (SiC) are mixed by a mixer for 48 hours to fully mix the raw materials to obtain a mixed powder; wherein, the equimolar ratio NbMoTaW high entropy alloy powder is prepared by vacuum melting followed by mechanical crushing and then plasma spheroidization treatment (for details, please refer to Guo Wei, Zheng Weijie, Zhao Mi, et al. A refractory high entropy alloy and its preparation method and application [P]. Hubei Province: CN202210485808.8, 2023-08-18. Wan Yixing, Liang Xiubing, Chen Yongxiong, et al. A method for preparing refractory high entropy alloy powder [P]. Jiangsu Province: CN202110068436.4, 2021-06-04.); the particle size distribution of the equimolar ratio NbMoTaW high entropy alloy powder is 20~53 μm; the particle size distribution of silicon powder and inert filler (SiC) is 2~5 μm; in the mixed powder, by mass percentage, it includes: 40% NbMoTaW high entropy alloy powder in equal molar ratio, 12% silicon powder, 8% infiltration agent (NH 4 F) and 40% inert filler (SiC);

[0038] (2) The mixed powder is placed in a corundum crucible, sealed, and placed in a high-temperature furnace for sintering at 1200°C for 12 h in an inert gas (argon) atmosphere, followed by cooling in the furnace to allow the NbMoTaW high entropy alloy powders with equal molar ratios to react in situ to generate (Nb, Mo, Ta, W)Si 2 High entropy silicide powder;

[0039] (3) The powder obtained in step (2) is vibrated and sieved to separate (Nb, Mo, Ta, W)Si with a particle size distribution of 20-53 μm. 2 High entropy silicide powder.

[0040] The (Nb, Mo, Ta, W)Si prepared in Example 1 2 The high entropy silicide powder was subjected to EDS point scanning composition analysis. The results showed that (Nb, Mo, Ta, W)Si 2 The relative atomic percentages of the elements in the high entropy silicide powder are: 63.9% Si, 9.6% Nb, 9.8% Mo, 9.1% Ta, 8.6% W, which confirms that the powder is M Si 2 type silicide, and each element (Nb, Mo, Ta, W, Si) is evenly distributed in the particles.

[0041] Example 2 (Hf, Nb, Zr, Ta, Ti)Si 2 Preparation of high entropy silicide powder

[0042] A (Hf, Nb, Zr, Ta, Ti)Si 2 The method for preparing high entropy silicide powder comprises the following steps:

[0043] (1) HfNbZrTaTi high entropy alloy powder, silicon powder, catalyst (NaF) and inert filler (Al 2 O 3 ) are mixed in a mixer for 24 h to fully mix the raw materials to obtain a mixed powder; wherein, the equimolar HfNbZrTaTi high entropy alloy powder is prepared by atomization powder making process (for details, please refer to Shen Baolong, Li Yongjie, Wang Qianqian, et al. A FeCoNiMo high entropy alloy powder oxygen evolution catalyst and its preparation method [P]. Jiangsu Province: CN202111338493.6, 2022-11-08.); the particle size distribution of the equimolar HfNbZrTaTi high entropy alloy powder is 20~150 μm; silicon powder and inert filler (Al 2 O 3) has a particle size distribution of 2~10 μm; in the mixed powder, by mass percentage, it includes: 40% equimolar HfNbZrTaTi high entropy alloy powder, 15% silicon powder, 5% infiltration agent (NaF) and 40% inert filler (Al 2 O 3 );

[0044] (2) The mixed powder was placed in a graphite crucible, sealed, and placed in a high-temperature furnace in an inert gas (argon) atmosphere at 1150°C for 15 h, followed by cooling in the furnace to allow the HfNbZrTaTi high entropy alloy powders with equal molar ratios to react in situ to generate (Hf, Nb, Zr, Ta, Ti)Si 2 High entropy silicide powder;

[0045] (3) The powder obtained in step (2) is vibrated and sieved to separate (Hf, Nb, Zr, Ta, Ti)Si with a particle size distribution of 20-150 μm. 2 High entropy silicide powder.

[0046] Example 3 (Ta, Nb, W, Ti, Hf)Si 2 Preparation of high entropy silicide powder

[0047] A (Ta, Nb, W, Ti, Hf)Si 2 The method for preparing high entropy silicide powder comprises the following steps:

[0048] (1) TaNbWTiHf (40% Ta, 15% Nb, 15% W, 15% Ti and 15% Hf in relative atomic percentage) high entropy alloy powder, silicon powder, catalyst (NaF) and inert filler (SiO 2 ) are mixed by a mixer for 36 h to fully mix the raw materials to obtain a mixed powder; wherein, TaNbWTiHf high entropy alloy powder is prepared by mechanical alloying followed by agglomeration granulation process (for details, please refer to Tang Yu, Li Shun, Bai Shuxin, et al. Preparation method of NbZrTiTa refractory high entropy alloy powder and NbZrTiTa refractory high entropy alloy powder [P]. Hunan Province: CN201811183559.7, 2019-01-01. Liu Hongxi, Zhang Lulu, Zhang Xiaowei, et al. A kind of AlNbMoVTi high entropy alloy powder and its application [P]. Yunnan Province: CN201811572880.4, 2019-03-12. Wang Liuying, Liu Gu, Wang Weichao, et al. Preparation method of titanium silicon carbide / AT13 high temperature radar absorbing coating [P]. Shaanxi Province: CN202211331899.6, 2024-04-05.) The particle size distribution of TaNbWTiHf high entropy alloy powder is 150~200 μm; silicon powder and inert filler (SiO 2) has a particle size distribution of 2~10 μm; in the mixed powder, by mass percentage, it includes: 35% TaNbWTiHf high entropy alloy powder, 20% silicon powder, 5% catalyst (NaF) and 40% inert filler (SiO 2 );

[0049] (2) The mixed powder was placed in a zirconia crucible, sealed, and placed in a high-temperature furnace in an inert gas (argon) atmosphere at 1050°C for 20 h, followed by cooling in the furnace to allow the TaNbWTiHf high entropy alloy powder to react in situ to generate (Ta, Nb, W, Ti, Hf)Si 2 High entropy silicide powder;

[0050] (3) The powder obtained in step (2) is vibrated and sieved to separate (Ta, Nb, W, Ti, Hf)Si with a particle size distribution of 150-200 μm. 2 High entropy silicide powder.

[0051] Example 4 (Nb, Mo, Ta, W)Si 2 Application of high entropy silicide powder in the preparation of anti-oxidation coating

[0052] The (Nb, Mo, Ta, W)Si prepared in Example 1 2 The application of high entropy silicide powder in the preparation of an anti-oxidation coating comprises the following steps:

[0053] Preparation of (Nb, Mo, Ta, W)Si on the surface of refractory alloy (Nb alloy) by spark plasma sintering 2 High entropy silicide coating, where the key parameters of the spark plasma sintering process are as follows: heating rate 100 ℃ / min, sintering temperature 1400 ℃, and holding time 5 min.

[0054] The coating samples were placed in a high-temperature box furnace for 1600 °C oxidation resistance test. The test standard was: "Test Method for Determination of Oxidation Resistance of Steel and High-Temperature Alloys", HB 5258-2000, Aviation Industry Standard of the People's Republic of China. After 100 h of oxidation, the samples were taken out and a uniform and dense oxide film was observed on the surface of the coating samples. No coating failure behaviors such as oxide film peeling and oxidation in the substrate were found. It can be seen that the (Nb, Mo, Ta, W)Si obtained in Example 1 2 The coating prepared from the high entropy silicide powder in Example 4 exhibits excellent anti-oxidation performance at 1600° C., and can provide good anti-oxidation protection (thermal protection) for the refractory alloy (Nb alloy) substrate.

[0055] In summary, the present invention adopts a solid powder siliconizing process to react high entropy alloy powder in situ to generate high entropy silicide powder, and utilizes the difference in particle size between high entropy silicide powder and inert filler to perform vibration screening, and separates high entropy silicide powder, thereby obtaining a set of components with high adjustability, high purity, uniform structure, controllable particle size, and uniform element distribution, which can be suitable for the use requirements of powder metallurgy, thermal spraying, and 3D printing, and the coating obtained has the advantages of good high temperature oxidation resistance, etc. M Si 2 Type high entropy silicide powder.

[0056] The preferred specific implementation modes and embodiments of the present invention are described in detail above, but the present invention is not limited to the above implementation modes and embodiments, and various changes can be made within the knowledge scope of those skilled in the art without departing from the concept of the present invention.

Claims

1. A M The method for preparing Si2 high entropy silicide powder is characterized in that: The steps include: (1) By mass fraction, 30-50% high entropy alloy powder, 10-30% silicon powder, 2-10% infiltration agent and 30-50% inert filler are mixed by a mixer to obtain a mixed powder; the high entropy alloy powder comprises at least three metal elements of Ta, W, Nb, Mo, V, Zr, Hf, Ti and Cr, wherein the particle size of the high entropy alloy powder is 20-200 μm; the particle size of the silicon powder and the inert filler is not greater than 10 μm, wherein the infiltration agent is one or a combination of NaF or NH4F, and the inert filler is at least one of Al2O3, SiO2 or SiC; (2) Sintering the mixed powder at a medium-high temperature of 1050-1200°C for 12-20 hours under an inert gas atmosphere to allow the high entropy alloy powder to react in situ to generate high entropy silicide powder; (3) Vibrate and sieve the high entropy silicide powder to separate M Si2 type high entropy silicide powder.

2. The method according to claim 1, characterized in that In step (1), the high entropy alloy powder includes at least three metal elements of Ta, W, Nb, Mo, V, Zr, Hf, Ti, and Cr, and the molar percentage content of each metal element is 15-40%.

3. The method according to claim 1, characterized in that: In step (1), the high entropy alloy powder is prepared by atomization, mechanical crushing after vacuum smelting, mechanical alloying, spray granulation or plasma spheroidization.

4. Prepared by any one of the preparation methods in claims 1-3 M Si2 type high entropy silicide powder.

5. According to claim 4 M Si2 type high entropy silicide powder, characterized in that: The particle size is 20~200 μm, and the elements are evenly distributed. In terms of atomic percentage, Si atoms account for 60~70% and metal elements account for 30~40%.

6. Prepared by any one of the preparation methods of claims 1 to 3 M Application of Si2 type high entropy silicide powder in preparing oxidation-resistant coating on refractory alloy or carbon / carbon composite material.

7. The use according to claim 6, characterized in that: The method for preparing the anti-oxidation coating is thermal spraying, laser cladding, slurry sintering, hot pressing sintering or spark plasma sintering.

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