Method for preparing high entropy alloy powder and method for preparing obtained powder and coating

Abstract

The present invention relates to a method for preparing a high-entropy alloy powder and a method for preparing the resulting powder and coating, specifically to the technical field of high-entropy alloys. The method comprises: mixing a metal precursor powder, a binder, and a dispersant to obtain a slurry; spray-granulating the resulting slurry to obtain a precursor powder; and reducing and sintering the resulting precursor powder to obtain a FeCoNiMnAl high-entropy alloy powder. The preparation method provided by the present invention, through the use of a specific preparation process, enables the obtained FeCoNiMnAl high-entropy alloy powder to be used as a raw material for plasma spraying, thereby obtaining an FeCoNiMnAl high-entropy alloy coating with excellent performance, thereby facilitating the preparation of a coating with high mechanical properties, corrosion resistance, and wave-absorbing properties.

Description

Technical Field

[0001] The present invention relates to the technical field of high entropy alloys, and in particular to a method for preparing high entropy alloy powder and a method for preparing the obtained powder and coating. Background Art

[0002] High-entropy alloys (HEAs) are typically composed of five or more elements. Their high mixing entropy effect facilitates the formation of simple solid solutions or amorphous structures. Unlike traditional intermetallic compounds or complex phase structures, HEAs exhibit lower free energy and higher phase stability. Their unique compositional design and phase structure endow them with high strength, high wear resistance, and excellent mechanical properties, among other special properties.

[0003] FeCoNiMnAl, a high-entropy alloy, exhibits excellent mechanical properties, corrosion resistance, and high electromagnetic wave absorption efficiency. Solid-solution strengthening of FeCoNiMnAl alloys results in a lattice distortion effect of a multi-principal element solid solution. Grain boundary strengthening and high-entropy effects reduce element diffusion rates, resulting in higher hardness and wear resistance. Furthermore, the multi-principal element design can provide improved thermal stability and high-temperature oxidation resistance, as the combined action of multiple elements reduces element diffusion and forms a dense oxide layer. In terms of corrosion resistance, the complex composition of high-entropy alloys can lead to superior performance in certain corrosive environments.

[0004] CN119681271A and CN117363922A respectively disclose a method for preparing FeCoNiMnAl high-entropy alloy powder, but do not provide further downstream processing technology of the powder nor mention whether it is suitable for thermal spraying technology. Therefore, there is an urgent need for a suitable and advanced processing technology to expand the application of FeCoNiMnAl high-entropy alloy powder to ensure its excellent performance.

[0005] Atmospheric plasma spraying uses arc-generated plasma as a heat source to heat coating powder to a molten or semi-molten state. The powder is then atomized by a high-speed airflow, sprayed and deposited at high speed onto the substrate surface. Compared with other spraying technologies, atmospheric plasma spraying offers faster preparation speeds, higher deposition efficiency, simpler operation procedures, and relatively low costs. However, conventional atmospheric plasma spraying still requires improvement due to issues such as oxidation during the spraying process, over-melting of powder particles, elemental burnout, uneven distribution of powder components in the plasma plume, and low deposition efficiency. Even under extreme operating conditions of high temperature, high wear, and severe corrosion (such as aircraft engine blades, gas turbine components, high-temperature molds, and offshore platform structures), the resulting coatings still exhibit poor performance. Summary of the Invention

[0006] In view of the problems existing in the prior art, the object of the present invention is to provide a method for preparing high entropy alloy powder and a method for preparing the obtained powder and coating, so as to solve the defects of FeCoNiMnAl high entropy alloy when used as a coating, such as poor mechanical properties, corrosion resistance and bonding performance with the substrate.

[0007] To achieve this object, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a method for preparing FeCoNiMnAl high entropy alloy powder, the preparation method comprising:

[0009] mixing metal precursor powder, a binder, and a dispersant to obtain a slurry;

[0010] The slurry is spray-granulated to obtain a precursor powder;

[0011] The precursor powder is reduced and sintered to obtain FeCoNiMnAl high entropy alloy powder.

[0012] The preparation method provided by the present invention adopts a specific preparation process, so that when the obtained FeCoNiMnAl high-entropy alloy powder is used as a raw material for plasma spraying, an FeCoNiMnAl high-entropy alloy coating with excellent performance can be obtained, which is conducive to the preparation of a coating with high mechanical properties, corrosion resistance, and wave absorption characteristics.

[0013] As a preferred technical solution of the present invention, the atomic ratio of Fe, Co, Ni, Mn and Al in the metal precursor powder is 1:1:1:1:0.5, and the specific surface area is greater than 50m 2 / g.

[0014] Preferably, the metal precursor powder is obtained by co-precipitation and calcination.

[0015] Preferably, the coprecipitation comprises: mixing a metal salt solution and an ammonium salt solution at a pH value of 8.5-9 to perform a coprecipitation reaction.

[0016] Preferably, the coprecipitation reaction temperature is 60-80°C.

[0017] Preferably, the coprecipitation reaction is assisted by stirring at a stirring speed of 400-500 r / min.

[0018] Preferably, the aging time of the coprecipitation reaction is ≥2h.

[0019] Preferably, the calcination comprises: calcining at 450-550° C. for ≥2 h in an air atmosphere.

[0020] As a preferred technical solution of the present invention, the mass percentage of the binder in the slurry is 1-2%.

[0021] Preferably, the mass percentage of the dispersant in the slurry is 0.5-1%.

[0022] Preferably, the viscosity of the slurry is 200-300 mPa·s.

[0023] Preferably, the solid content of the slurry is 25-30%.

[0024] Preferably, the rotation speed of the atomizer in the spray granulation is 18000-20000 r / min.

[0025] Preferably, the feed rate of the spray granulation is 20-30 mL / min.

[0026] Preferably, the feed inlet temperature of the spray granulation is 220-250°C.

[0027] Preferably, the discharge port temperature of the spray granulation is 90-100°C.

[0028] As a preferred technical solution of the present invention, the sintering atmosphere of the reduction sintering includes: hydrogen.

[0029] Preferably, the gas flow rate for forming the sintering atmosphere during the reduction sintering is 4-6 L / min.

[0030] Preferably, the temperature rise process of the reduction sintering is: when the temperature is less than 600°C, the temperature rise rate is 4-6°C / min; when the temperature is greater than or equal to 600°C, the temperature rise rate is 10-12°C / min.

[0031] Preferably, the holding temperature of the reduction sintering is 1100-1200°C.

[0032] Preferably, the holding time of the reduction sintering is ≥3h.

[0033] Preferably, the reduction sintering is followed by furnace cooling to obtain FeCoNiMnAl high entropy alloy powder.

[0034] In a second aspect, the present invention provides a FeCoNiMnAl high-entropy alloy powder, which is obtained by the preparation method described in the first aspect. The Hall flow rate of the FeCoNiMnAl high-entropy alloy powder is 22-26s / 50g, the oxygen mass percentage is ≤0.3%, and the sphericity is >90%.

[0035] In a third aspect, the present invention provides a method for preparing a FeCoNiMnAl high entropy alloy coating, the preparation method comprising:

[0036] The FeCoNiMnAl high entropy alloy powder as described in the second aspect is used as a raw material for plasma spraying, and then heat-treated to obtain a FeCoNiMnAl high entropy alloy coating;

[0037] The plasma spraying is assisted by dynamically reducing the magnetic field;

[0038] The dynamically reducing magnetic field includes: a first magnetic field, a second magnetic field and a third magnetic field that are reduced in sequence;

[0039] The first magnetic field is maintained for 20-22% of the plasma spraying time;

[0040] The second magnetic field is maintained for 60-62% of the plasma spraying time.

[0041] As a preferred technical solution of the present invention, the surface roughness Ra of the substrate used in the plasma spraying is 5-7 μm.

[0042] Preferably, the FeCoNiMnAl high entropy alloy powder used in the plasma spraying has a D50 particle size of 15-45 μm and a sphericity of >90%.

[0043] As a preferred technical solution of the present invention, the power of the plasma spraying is 35-50kW.

[0044] Preferably, the main gas flow rate of the plasma spraying is 40-50 SLPM.

[0045] Preferably, the auxiliary gas flow rate of the plasma spraying is 10-15 SLPM.

[0046] Preferably, the scanning speed of the plasma spraying is 120-180 m / min.

[0047] Preferably, the powder feeding rate of the plasma spraying is 20-40 g / min.

[0048] Preferably, the distance between the spray gun nozzle and the substrate surface during the plasma spraying is 100-150 mm.

[0049] Preferably, the temperature of the substrate surface during the plasma spraying is 50-150°C.

[0050] As a preferred technical solution of the present invention, the magnetic field strength of the first magnetic field is 1-1.2T.

[0051] Preferably, the magnetic field strength of the second magnetic field is 0.8-1T.

[0052] Preferably, the magnetic field strength of the third magnetic field is 0.5-0.8T.

[0053] Preferably, the distribution uniformity of the magnetic field in the dynamically reduced magnetic field is ≤3%.

[0054] As a preferred technical solution of the present invention, the heat treatment is supplemented with a magnetic field of 0.3-0.5T.

[0055] Preferably, the holding temperature of the heat treatment is 400-600°C.

[0056] Preferably, the holding time of the heat treatment is ≥1h.

[0057] Compared with the existing technical solutions, the present invention has the following beneficial effects:

[0058] (1) In the process of atmospheric plasma spraying of FeCoNiMnAl coating, the present invention introduces a gradient magnetic field, which accelerates and aggregates the plasma, causing the spraying speed of the magnetic metal particles to change, thereby improving the uniform distribution of the magnetic metal particles in the plasma flame with a magnetic field. The magnetic field has an aggregation and confinement effect on the plasma, reducing the non-uniformity and scattering of the sprayed material particles, which helps to improve the quality of the coating. The core of the process is to use the magnetic field to influence the motion trajectory and distribution of charged particles in the plasma, so that ferromagnetic particles (such as Fe, Co charged particles) can be uniformly deposited in the coating in a constant magnetic field, and the ferromagnetic particles are gradually deposited in the coating in a gradient magnetic field.

[0059] (2) In a magnetic field of 0.5-1.2T, ferromagnetic particles (such as Fe and Co charged particles) are oriented by the magnetic moment to form a special crystal structure along the direction of the magnetic field. The FeCoNiMnAl high entropy alloy coating has a significant potential in the field of microwave absorption due to its multi-principal element synergistic effect and controllable electromagnetic properties. The magnetic field optimizes the grain orientation of the magnetic particles and enhances the magnetic anisotropy. It has unique advantages in high frequency bands (X / Ku band) and high temperature environments. Furthermore, the magnetic field assisted plasma spraying process, by applying a transverse magnetic field to change the trajectory of the charged particles, increases the deposition efficiency to 80-85%. The special structural orientation can increase the coating hardness by 20%-30%.

[0060] (3) The high entropy alloy coating of the present invention has a nano-precipitated phase during the spray deposition and cooling process: an in-situ generated B2 / L12 ordered phase (size <50nm), which greatly improves the fracture toughness of the coating compared to traditional coatings of the same elements. At the same time, the coating quickly forms a partially amorphous structure during CO2 gas deposition and cooling. During service, the coating has a dynamic recrystallization inhibition effect: the high entropy effect reduces the element diffusion rate (the diffusion coefficient is reduced by 2 orders of magnitude), and the high entropy alloy can inhibit the upward diffusion of matrix elements (especially Ti), greatly improving the service life of the coating in high-temperature environments. In terms of corrosion resistance, the coating has an element synergistic effect: Fe / Co / Ni delays Cl⁻ penetration, which can increase the critical pitting potential and effectively reduce the corrosion rate of the coating. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 This is the XRD diffraction pattern of the FeCoNiMnAl high entropy alloy coating obtained in Example 1 of the present invention.

[0062] Figure 2 This is a SEM photograph of the FeCoNiMnAl high-entropy alloy coating obtained in Example 1 of the present invention.

[0063] The present invention is further described in detail below. However, the following examples are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims. DETAILED DESCRIPTION

[0064] To better illustrate the present invention and facilitate understanding of the technical solutions of the present invention, typical but non-limiting embodiments of the present invention are as follows:

[0065] At present, when FeCoNiMnAl high entropy alloy coatings are prepared by atmospheric plasma spraying, the compatibility between the FeCoNiMnAl high entropy alloy powder used and the plasma spraying is poor, resulting in poor performance of the coating obtained by plasma spraying, such as poor mechanical properties, corrosion resistance and bonding properties, and cannot be applied to more stringent working conditions. Based on this, the present invention proposes a method for preparing FeCoNiMnAl high entropy alloy powder to ensure that the obtained powder has good compatibility with plasma spraying, thereby ensuring the performance of the obtained FeCoNiMnAl high entropy alloy coating, which is specifically as follows:

[0066] This embodiment provides a method for preparing FeCoNiMnAl high entropy alloy powder, the preparation method comprising:

[0067] mixing metal precursor powder, a binder, and a dispersant to obtain a slurry;

[0068] The slurry is spray-granulated to obtain a precursor powder;

[0069] The precursor powder is reduced and sintered to obtain FeCoNiMnAl high entropy alloy powder.

[0070] The atomic ratio of Fe, Co, Ni, Mn and Al in the metal salt precursor solution is 1:1:1:1:0.5, and the specific surface area is greater than 50m 2 / g.

[0071] Wherein, the metal precursor powder is obtained by co-precipitation and calcination.

[0072] The coprecipitation comprises mixing a metal salt solution and an ammonium salt solution and performing a coprecipitation reaction at a pH value of 8.5-9, for example, 8.5, 8.6, 8.7, 8.8, 8.9 or 9, etc., but is not limited to the listed values, and other values ​​not listed within the range also meet the requirements.

[0073] In the present invention, the metal salt solution is obtained by mixing the elements Fe, Co, Ni, Mn and Al in water using soluble salts according to atomic ratios, such as sulfate, nitrate, chloride, etc. The ammonium salt solution can be a solution of ammonium bicarbonate and / or ammonium carbonate.

[0074] The total mass concentration of the metal salt solution is 4-5 mol / L, the mass concentration of the ammonium salt solution is 1-2 mol / L, and the mass ratio of the metal salt solution to the ammonium salt solution during mixing is 1:(6-8).

[0075] Among them, the total mass concentration of the metal salt solution is 4-5 mol / L, for example, it can be 4 mol / L, 4.1 mol / L, 4.2 mol / L, 4.3 mol / L, 4.4 mol / L, 4.5 mol / L, 4.6 mol / L, 4.7 mol / L, 4.8 mol / L, 4.9 mol / L or 5 mol / L, but is not limited to the listed values. Other values ​​not listed within this range also meet the requirements.

[0076] The mass concentration of the ammonium salt solution is 1-2 mol / L, for example, 1 mol / L, 1.1 mol / L, 1.2 mol / L, 1.3 mol / L, 1.4 mol / L, 1.5 mol / L, 1.6 mol / L, 1.7 mol / L, 1.8 mol / L, 1.9 mol / L or 2 mol / L, but is not limited to the listed values. Other values ​​not listed within this range also meet the requirements.

[0077] Among them, the mass ratio of the metal salt solution and the ammonium salt solution during mixing is 1:(6-8), for example, it can be 1:6, 1:6.2, 1:6.4, 1:6.6, 1:6.8, 1:7, 1:7.2, 1:7.4, 1:7.6, 1:7.8 or 1:8, etc., but is not limited to the listed values. Other values ​​not listed within this range also meet the requirements.

[0078] The temperature of the coprecipitation reaction is 60-80°C, for example, 60°C, 65°C, 70°C, 75°C or 80°C, but is not limited to the listed values. Other values ​​not listed within this range also meet the requirements.

[0079] The coprecipitation reaction is assisted by stirring at a stirring speed of 400-500 r / min, for example, 400 r / min, 420 r / min, 440 r / min, 460 r / min, 480 r / min or 500 r / min, but is not limited to the listed values. Other values ​​not listed within this range also meet the requirements.

[0080] The aging time of the coprecipitation reaction is ≥2 h, for example, 2 h, 2.5 h, 3 h, 3.5 h, 4 h, 4.5 h or 5 h, but is not limited to the listed values. Other values ​​not listed within this range also meet the requirements.

[0081] Wherein, the calcination includes: calcining at 450-550°C for ≥2h in an air atmosphere, the calcination temperature is 450°C, 460°C, 480°C, 500°C, 520°C, 540°C or 550°C, etc., and the calcination time is 2h, 3h, 4h or 5h, etc., but is not limited to the listed values. Other values ​​not listed in this range also meet the requirements.

[0082] The mass percentage of the binder in the slurry is 1-2%, for example, it can be 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9% or 2%, but is not limited to the listed values. Other values ​​not listed within this range also meet the requirements.

[0083] The mass percentage of the dispersant in the slurry is 0.5-1%, for example, it can be 0.5%, 0.55%, 0.65%, 0.7%, 0.75%, 0.8%, 0.85%, 0.9%, 0.95% or 1%, etc., but is not limited to the listed values. Other values ​​not listed within this range also meet the requirements.

[0084] In the present invention, the dispersant used in the spray granulation can be any dispersant commonly used in the art, such as ammonium polyacrylate (with a degree of polymerization of 20-50).

[0085] In the present invention, the binder used in the spray granulation can be a commonly used binder in the art, such as polyvinyl alcohol (with a degree of polymerization of 500-2000).

[0086] The viscosity of the slurry is 200-300 mPa·s, for example, it can be 200 mPa·s, 210 mPa·s, 220 mPa·s, 230 mPa·s, 240 mPa·s, 250 mPa·s, 260 mPa·s, 270 mPa·s, 280 mPa·s, 290 mPa·s or 300 mPa·s, etc., but is not limited to the listed values. Other values ​​not listed within this range also meet the requirements.

[0087] The solid content of the slurry is 25-30%, for example, it can be 25%, 25.5%, 26%, 26.5%, 27%, 27.5%, 28%, 28.5%, 29%, 29.5% or 30%, etc., but is not limited to the listed values. Other values ​​not listed within this range also meet the requirements.

[0088] The atomizer speed in the spray granulation is 18000-20000 r / min, for example, it can be 18000 r / min, 18500 r / min, 19000 r / min, 19500 r / min or 20000 r / min, but is not limited to the listed values. Other values ​​not listed within this range also meet the requirements.

[0089] The feed rate of the spray granulation is 20-30 mL / min, for example, 20 mL / min, 22 mL / min, 24 mL / min, 26 mL / min, 28 mL / min or 30 mL / min, but is not limited to the listed values. Other values ​​not listed within this range also meet the requirements.

[0090] The feed inlet temperature of the spray granulation is 220-250°C, for example, 220°C, 225°C, 230°C, 235°C, 240°C, 245°C or 250°C, but is not limited to the listed values. Other values ​​not listed within this range also meet the requirements.

[0091] The discharge port temperature of the spray granulation is 90-100°C, for example, 90°C, 92°C, 94°C, 96°C, 98°C or 100°C, but is not limited to the listed values. Other values ​​not listed within this range also meet the requirements.

[0092] Wherein, the sintering atmosphere of the reduction sintering includes: hydrogen.

[0093] Among them, the gas flow rate for forming the sintering atmosphere during the reduction sintering is 4-6 L / min, for example, it can be 4 L / min, 4.5 L / min, 5 L / min, 5.5 L / min or 6 L / min, etc., but is not limited to the listed values. Other values ​​not listed within this range also meet the requirements.

[0094] Among them, the heating process of the reduction sintering is: when the temperature is less than 600°C, the heating rate is 4-6°C / min; when the temperature is greater than or equal to 600°C, the heating rate is 10-12°C / min. The heating rate of less than 600°C can be, for example, 4°C / min, 4.5°C / min, 5°C / min, 5.5°C / min or 6°C / min, and the heating rate of greater than or equal to 600°C can be, for example, 10°C / min, 10.5°C / min, 11°C / min, 11.5°C / min or 12°C / min, but is not limited to the listed values. Other values ​​not listed within this range also meet the requirements.

[0095] The holding temperature of the reduction sintering is 1100-1200°C, for example, it can be 1100°C, 1120°C, 1140°C, 1160°C, 1180°C or 1200°C, but is not limited to the listed values. Other values ​​not listed in this range also meet the requirements.

[0096] The holding time of the reduction sintering is ≥3h, for example, it can be 3h, 3.5h, 4h, 4.5h or 5h, etc., but is not limited to the listed values. Other values ​​not listed within this range also meet the requirements.

[0097] Wherein, the reduction sintering is followed by furnace cooling to obtain FeCoNiMnAl high entropy alloy powder.

[0098] Furthermore, this embodiment provides a FeCoNiMnAl high entropy alloy powder, which is obtained by the preparation method as described above. The Hall flow rate of the FeCoNiMnAl high entropy alloy powder is 22-26s / 50g, the oxygen mass percentage is ≤0.3%, and the sphericity is >90%.

[0099] Furthermore, although the coating obtained through the above optimization has excellent performance, it still has certain defects. Based on this, the present invention further optimizes the preparation process of the coating to further improve the performance of the obtained coating, as follows:

[0100] This embodiment provides a method for preparing a FeCoNiMnAl high-entropy alloy coating, the preparation method comprising:

[0101] The FeCoNiMnAl high entropy alloy powder as described above is used as a raw material for plasma spraying, and then heat treated to obtain a FeCoNiMnAl high entropy alloy coating;

[0102] The plasma spraying is assisted by dynamically reducing the magnetic field;

[0103] The dynamically decreasing magnetic field includes: a first magnetic field, a second magnetic field, and a third magnetic field that decrease in sequence.

[0104] The first magnetic field is maintained for 20-22% of the plasma spraying time, for example, 20%, 20.5%, 21%, 21.5% or 22%, but is not limited to the listed values. Other values ​​not listed within this range also meet the requirements.

[0105] The second magnetic field is maintained for 60-62% of the plasma spraying time, for example, 60%, 60.5%, 61%, 61.5% or 62%, etc., but is not limited to the listed values. Other values ​​not listed within this range also meet the requirements.

[0106] The remaining time after excluding the maintenance time of the first magnetic field and the maintenance time of the second magnetic field is the time for maintaining the third magnetic field.

[0107] The surface roughness Ra of the substrate used in the plasma spraying is 5-7 μm, for example, 5 μm, 5.5 μm, 6 μm, 6.5 μm or 7 μm, but is not limited to the listed values. Other values ​​not listed within this range also meet the requirements.

[0108] In the present invention, the substrate used for plasma spraying can be selected as workpieces such as aircraft engine blades, gas turbine components, high-temperature molds, marine platform structures, etc., and the specific material can be nickel-based high-temperature alloys or titanium alloys. The specific spraying time can be reasonably selected based on the required coating thickness.

[0109] The D50 particle size of the FeCoNiMnAl high entropy alloy powder used in the plasma spraying is 15-45 μm, and the sphericity is greater than 90%. The D50 particle size can be, for example, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm or 45 μm, but is not limited to the listed values. Other values ​​not listed within this range also meet the requirements.

[0110] The power of the plasma spraying is 35-50kW, for example, 35kW, 36kW, 38kW, 40kW, 42kW, 44kW, 46kW, 48kW or 50kW, but is not limited to the listed values. Other values ​​not listed within the range also meet the requirements.

[0111] The main gas flow rate of the plasma spraying is 40-50 SLPM, for example, it can be 40 SLPM, 42 SLPM, 44 SLPM, 46 SLPM, 48 SLPM or 50 SLPM, but is not limited to the listed values. Other values ​​not listed within this range also meet the requirements.

[0112] The auxiliary gas flow rate of the plasma spraying is 10-15 SLPM, for example, it can be 10 SLPM, 11 SLPM, 12 SLPM, 13 SLPM, 14 SLPM or 15 SLPM, but is not limited to the listed values. Other values ​​not listed in this range also meet the requirements.

[0113] In the present invention, the main gas and auxiliary gas used in plasma spraying can be selected and designed according to conventional requirements in the field, such as argon as the main gas and hydrogen and / or helium as the auxiliary gas.

[0114] The scanning speed of the plasma spraying is 120-180 m / min, for example, it can be 120 m / min, 130 m / min, 140 m / min, 150 m / min, 160 m / min, 170 m / min or 180 m / min, but is not limited to the listed values. Other values ​​not listed within this range also meet the requirements.

[0115] The powder feeding rate of the plasma spraying is 20-40 g / min, for example, it can be 20 g / min, 25 g / min, 30 g / min, 35 g / min or 40 g / min, but is not limited to the listed values. Other values ​​not listed in this range also meet the requirements.

[0116] The distance between the spray gun nozzle and the substrate surface during the plasma spraying is 100-150 mm, for example, 100 mm, 110 mm, 120 mm, 130 mm, 140 mm or 150 mm, but is not limited to the listed values. Other values ​​not listed within this range also meet the requirements.

[0117] The temperature of the substrate surface during the plasma spraying is 50-150°C, for example, 50°C, 60°C, 80°C, 100°C, 120°C, 140°C or 150°C, but is not limited to the listed values. Other values ​​not listed within this range also meet the requirements.

[0118] The magnetic field strength of the first magnetic field is 1-1.2T, for example, it can be 1T, 1.05T, 1.1T, 1.15T or 1.2T, etc., but is not limited to the listed values. Other values ​​not listed in this range also meet the requirements.

[0119] The magnetic field strength of the second magnetic field is 0.8-1T, for example, it can be 0.8T, 0.85T, 0.9T, 0.95T or 1T, etc., but is not limited to the listed values. Other values ​​not listed in this range also meet the requirements.

[0120] The magnetic field strength of the third magnetic field is 0.5-0.8 T, for example, it can be 0.5 T, 0.55 T, 0.6 T, 0.65 T, 0.7 T, 0.75 T or 0.8 T, etc., but is not limited to the listed values. Other values ​​not listed in this range also meet the requirements.

[0121] The distribution uniformity of the magnetic field in the dynamically reduced magnetic field is ≤3%, for example, it can be 3%, 2.5%, 2%, 1.5%, 1%, 0.5% or 0.1%, etc., but is not limited to the listed values. Other values ​​not listed within this range also meet the requirements.

[0122] In the present invention, the uniformity of magnetic field distribution refers to the fluctuation of magnetic induction intensity of the magnetic field within a certain volume within the spraying range of ≤3%.

[0123] The heat treatment is supplemented with a magnetic field of 0.3-0.5 T, for example, 0.3 T, 0.35 T, 0.4 T, 0.45 T or 0.5 T, etc., but is not limited to the listed values. Other values ​​not listed within this range also meet the requirements.

[0124] The holding temperature of the heat treatment is 400-600°C, for example, it can be 400°C, 450°C, 500°C, 550°C or 600°C, but is not limited to the listed values. Other values ​​not listed in this range also meet the requirements.

[0125] The holding time of the heat treatment is ≥1h, for example, it can be 1h, 1.5h, 2h, 2.5h or 3h, etc., but is not limited to the listed values. Other values ​​not listed within this range also meet the requirements.

[0126] Furthermore, in order to illustrate the effect that can be achieved when the FeCoNiMnAl high entropy alloy powder provided by the present invention is used for coating preparation, the following example scheme is used for exemplary description, as follows.

[0127] Example 1:

[0128] This embodiment provides a preparation method and utilization process of FeCoNiMnAl high entropy alloy powder, which are specifically as follows:

[0129] mixing metal precursor powder, a binder, and a dispersant to obtain a slurry;

[0130] The obtained slurry is spray granulated to obtain a precursor powder;

[0131] The obtained precursor powder is subjected to reduction sintering to obtain FeCoNiMnAl high entropy alloy powder;

[0132] The metal precursor powder is obtained by coprecipitation and calcination. The coprecipitation comprises: mixing a metal salt solution with a total molar concentration of 4.5 mol / L (obtained by mixing the elements Fe, Co, Ni, Mn and Al in water using soluble sulfate according to an atomic ratio) with a molar concentration of 1.5 mol / L ammonium salt solution (ammonium carbonate) at a mass ratio of 1:7, and then performing a coprecipitation reaction at a pH value of 8.8. The coprecipitation reaction temperature is 70°C, with stirring at a speed of 450 r / min, and aging for 2 hours. The calcination comprises: calcining at 500°C for 2 hours in an air atmosphere. The atomic ratio of Fe, Co, Ni, Mn and Al in the obtained metal precursor powder is 1:1:1:1:0.5, and the specific surface area is 60m 2 / g;

[0133] The mass percentage of the binder (polyvinyl alcohol, degree of polymerization of 1250) in the slurry is 1.5%, the mass percentage of the dispersant (ammonium polyacrylate, degree of polymerization of 35) is 0.8%, the viscosity of the slurry is 250 mPa·s, and the solid content of the slurry is 28%;

[0134] The atomizer speed in the spray granulation was 19000 r / min, the feed rate was 25 mL / min, the feed port temperature was 235°C, and the discharge port temperature was 95°C;

[0135] The sintering atmosphere of the reduction sintering includes hydrogen, the gas flow rate of the sintering atmosphere is 5 L / min, the heating process is: when the temperature is less than 600°C, the heating rate is 5°C / min, when the temperature is greater than or equal to 600°C, the heating rate is 11°C / min, the holding temperature is 1150°C, and the holding time is 3 hours. After the reduction sintering, the powder is cooled in the furnace to obtain the FeCoNiMnAl high-entropy alloy powder.

[0136] Furthermore, the obtained powder is used as a powder raw material for plasma spraying to prepare a coating, specifically as follows:

[0137] FeCoNiMnAl high entropy alloy powder is used as raw material for plasma spraying, and then heat treatment is performed to obtain FeCoNiMnAl high entropy alloy coating;

[0138] The surface roughness Ra of the substrate used in the plasma spraying is 6 μm, the D50 particle size of the FeCoNiMnAl high entropy alloy powder used is 30 μm, the sphericity is 95%, and the Hall flow rate is 24 s / 50 g;

[0139] The plasma spraying power was 40 kW, the main gas (argon) flow rate was 45 SLPM, the auxiliary gas (helium) flow rate was 12 SLPM, the scanning speed was 150 m / min, the powder feeding rate was 30 g / min, the distance between the spray gun nozzle and the substrate surface was 125 mm, and the substrate surface temperature was 100°C.

[0140] The heat treatment is carried out at a holding temperature of 500° C. and a holding time of 1 h.

[0141] Example 2:

[0142] This embodiment provides a preparation method and utilization process of FeCoNiMnAl high entropy alloy powder, which are specifically as follows:

[0143] mixing metal precursor powder, a binder, and a dispersant to obtain a slurry;

[0144] The obtained slurry is spray granulated to obtain a precursor powder;

[0145] The obtained precursor powder is subjected to reduction sintering to obtain FeCoNiMnAl high entropy alloy powder;

[0146] The metal precursor powder is obtained by coprecipitation and calcination. The coprecipitation comprises: mixing a metal salt solution with a total molar concentration of 5 mol / L (obtained by mixing the elements Fe, Co, Ni, Mn and Al in water using soluble sulfate according to an atomic ratio) with a molar concentration of 1 mol / L ammonium salt solution (ammonium carbonate) in a mass ratio of 1:6, and then performing a coprecipitation reaction at a pH value of 9. The coprecipitation reaction temperature is 80° C., with stirring at a speed of 500 r / min, and aging for 2 hours. The calcination comprises: calcining at 550° C. for 2 hours in an air atmosphere. The atomic ratio of Fe, Co, Ni, Mn and Al in the obtained metal precursor powder is 1:1:1:1:0.5, and the specific surface area is 80 m 2 / g;

[0147] The mass percentage of the binder (polyvinyl alcohol, degree of polymerization of 500) in the slurry is 2%, the mass percentage of the dispersant (ammonium polyacrylate, degree of polymerization of 50) is 1%, the viscosity of the slurry is 200 mPa·s, and the solid content of the slurry is 30%;

[0148] The atomizer speed in the spray granulation was 20000 r / min, the feed rate was 20 mL / min, the feed port temperature was 250° C., and the discharge port temperature was 100° C.;

[0149] The sintering atmosphere of the reduction sintering includes hydrogen, the gas flow rate of the sintering atmosphere is 6 L / min, the heating process is: when the temperature is less than 600°C, the heating rate is 6°C / min, when the temperature is greater than or equal to 600°C, the heating rate is 10°C / min, the holding temperature is 1200°C, and the holding time is 3 hours. After the reduction sintering, the powder is cooled in the furnace to obtain the FeCoNiMnAl high-entropy alloy powder.

[0150] Furthermore, the obtained powder is used as a powder raw material for plasma spraying to prepare a coating, specifically as follows:

[0151] FeCoNiMnAl high entropy alloy powder is used as raw material for plasma spraying, and then heat treatment is performed to obtain FeCoNiMnAl high entropy alloy coating;

[0152] The surface roughness Ra of the substrate used in the plasma spraying is 7 μm, the D50 particle size of the FeCoNiMnAl high entropy alloy powder used is 45 μm, the sphericity is 96%, and the Hall flow rate is 22 s / 50 g;

[0153] The plasma spraying power is 50 kW, the main gas (argon) flow rate is 50 SLPM, the auxiliary gas (helium) flow rate is 10 SLPM, the scanning speed is 180 m / min, the powder feeding rate is 20 g / min, the distance between the spray gun nozzle and the substrate surface is 150 mm, and the substrate surface temperature is 50-150°C;

[0154] The heat treatment is carried out at a holding temperature of 600° C. and a holding time of 1 hour.

[0155] Example 3:

[0156] This embodiment provides a preparation method and utilization process of FeCoNiMnAl high entropy alloy powder, which are specifically as follows:

[0157] mixing metal precursor powder, a binder, and a dispersant to obtain a slurry;

[0158] The obtained slurry is spray granulated to obtain a precursor powder;

[0159] The obtained precursor powder is subjected to reduction sintering to obtain FeCoNiMnAl high entropy alloy powder;

[0160] The metal precursor powder is obtained by coprecipitation and calcination. The coprecipitation comprises: mixing a metal salt solution with a total molar concentration of 4 mol / L (obtained by mixing the elements Fe, Co, Ni, Mn and Al in water using soluble sulfate according to an atomic ratio) with a molar concentration of 2 mol / L ammonium salt solution (ammonium bicarbonate) in a mass ratio of 1:8, and then performing a coprecipitation reaction at a pH value of 8.5. The coprecipitation reaction temperature is 60°C, with stirring at a speed of 400 r / min, and aging for 3 hours. The calcination comprises: calcining at 450°C for 4 hours in an air atmosphere. The atomic ratio of Fe, Co, Ni, Mn and Al in the obtained metal precursor powder is 1:1:1:1:0.5, and the specific surface area is 70m 2 / g;

[0161] The mass percentage of the binder (polyvinyl alcohol, degree of polymerization of 2000) in the slurry is 1%, the mass percentage of the dispersant (ammonium polyacrylate, degree of polymerization of 20) is 0.5%, the viscosity of the slurry is 300 mPa·s, and the solid content of the slurry is 25%;

[0162] The atomizer speed in the spray granulation was 18000 r / min, the feed rate was 30 mL / min, the feed port temperature was 220°C, and the discharge port temperature was 90°C;

[0163] The sintering atmosphere of the reduction sintering is hydrogen, the gas flow rate forming the sintering atmosphere is 4 L / min, the heating process is: when the temperature is less than 600°C, the heating rate is 4°C / min, when the temperature is greater than or equal to 600°C, the heating rate is 12°C / min, the holding temperature is 1100°C, and the holding time is 4 hours. After reduction sintering, the FeCoNiMnAl high-entropy alloy powder is obtained by furnace cooling.

[0164] Furthermore, the obtained powder is used as a powder raw material for plasma spraying to prepare a coating, specifically as follows:

[0165] FeCoNiMnAl high entropy alloy powder is used as raw material for plasma spraying, and then heat treatment is performed to obtain FeCoNiMnAl high entropy alloy coating;

[0166] The surface roughness Ra of the substrate used in the plasma spraying is 5 μm, the D50 particle size of the FeCoNiMnAl high entropy alloy powder used is 15 μm, the sphericity is 92%, and the Hall flow rate is 26 s / 50 g;

[0167] The plasma spraying power is 35kW, the main gas (argon) flow rate is 40SLPM, the auxiliary gas (hydrogen) flow rate is 15SLPM, the scanning speed is 120m / min, the powder feeding rate is 40g / min, the distance between the spray gun nozzle and the substrate surface is 100mm, and the substrate surface temperature is 50-150°C;

[0168] The heat treatment is carried out at a holding temperature of 400° C. and a holding time of 3 hours.

[0169] Comparative Example 1:

[0170] The only difference from Example 1 is that the metal precursor is replaced with a mixed powder of metal elements in equimolar amounts.

[0171] Example 4:

[0172] The only difference from Example 1 is that the solid content of the slurry is 20%.

[0173] Example 5:

[0174] The only difference from Example 1 is that the solid content of the slurry is 35%.

[0175] Example 6:

[0176] The only difference from Example 1 is that the calcination temperature is 800°C.

[0177] Example 7:

[0178] The only difference from Example 1 is that the holding temperature of the reduction sintering is 650°C.

[0179] When the above embodiments and comparative examples were sprayed, the substrate was nickel-based alloy inconel718, and the spraying time was 2 minutes. The coatings obtained in the above embodiments 1-7 and comparative example 1 were tested for mechanical properties and corrosion resistance, wherein the microhardness of the coating was measured according to the GB / T 4340.1-2009 implementation standard, the fracture toughness of the coating was measured according to the ISO 12135 indentation method implementation standard, the wear resistance of the coating was measured using the ASTM G65 rubber wheel abrasive wear test standard test, and the corrosion resistance of the coating was measured using GB / T 10125-2021: "Artificial atmosphere corrosion test salt spray test" and GB / T4334-2020: "Corrosion of metals and alloys - Laboratory uniform corrosion full immersion test method" to obtain the coating corrosion resistance measurement results. The results are detailed in Tables 1 and 2 below. The XRD pattern of the coating obtained in Example 1 is shown in Figure 2. Figure 1 As shown in the SEM photos Figure 2 shown.

[0180] Table 1

[0181]

[0182] Table 2

[0183]

[0184] In Table 2, the concentration of NaCl solution refers to mass concentration, and the concentration of H2SO4 solution refers to mass concentration.

[0185] Furthermore, in order to illustrate the effect that can be achieved by the magnetic field introduced during plasma spraying in the present invention, the following example is used for illustration.

[0186] Example 8:

[0187] The only difference from Example 1 is that the plasma spraying is assisted by dynamically reducing the magnetic field; the dynamically reducing magnetic field includes: a first magnetic field, a second magnetic field, and a third magnetic field that are reduced in sequence. The maintenance time of the first magnetic field is 21% of the plasma spraying time, the maintenance time of the second magnetic field is 61% of the plasma spraying time, and the remaining time is the maintenance time of the third magnetic field. The magnetic field strength of the first magnetic field is 1.1T, the magnetic field strength of the second magnetic field is 0.9T, the magnetic field strength of the third magnetic field is 0.6T, and the magnetic field distribution uniformity is 3%.

[0188] Example 9:

[0189] The only difference from Example 2 is that the plasma spraying is assisted by dynamically reducing the magnetic field; the dynamically reducing magnetic field includes: a first magnetic field, a second magnetic field, and a third magnetic field that are reduced in sequence. The maintenance time of the first magnetic field is 20% of the plasma spraying time, the maintenance time of the second magnetic field is 62% of the plasma spraying time, and the remaining time is the maintenance time of the third magnetic field. The magnetic field strength of the first magnetic field is 1T, the magnetic field strength of the second magnetic field is 0.8T, the magnetic field strength of the third magnetic field is 0.5T, and the magnetic field distribution uniformity is 2%.

[0190] Example 10:

[0191] The only difference from Example 3 is that the plasma spraying is assisted by dynamically reducing the magnetic field; the dynamically reducing magnetic field includes: a first magnetic field, a second magnetic field, and a third magnetic field that are reduced in sequence. The maintenance time of the first magnetic field is 22% of the plasma spraying time, the maintenance time of the second magnetic field is 60% of the plasma spraying time, and the remaining time is the maintenance time of the third magnetic field. The magnetic field strength of the first magnetic field is 1.2T, the magnetic field strength of the second magnetic field is 1T, the magnetic field strength of the third magnetic field is 0.8T, and the magnetic field distribution uniformity is 1%.

[0192] Example 11:

[0193] The only difference from Example 1 is that a 0.4 T magnetic field is used in the heat treatment.

[0194] Example 12:

[0195] The only difference from Example 2 is that a 0.3 T magnetic field is used in the heat treatment.

[0196] Example 13:

[0197] The only difference from Example 3 is that a 0.5 T magnetic field is used in the heat treatment.

[0198] Example 14:

[0199] The only difference from Example 1 is that the plasma spraying is supplemented by a dynamic magnetic field reduction; the dynamic magnetic field reduction includes: a first magnetic field, a second magnetic field, and a third magnetic field that are reduced in sequence. The first magnetic field is maintained for 21% of the plasma spraying time, the second magnetic field is maintained for 61% of the plasma spraying time, and the remaining time is the maintenance time of the third magnetic field. The magnetic field strength of the first magnetic field is 1.1T, the magnetic field strength of the second magnetic field is 0.9T, and the magnetic field strength of the third magnetic field is 0.7T. The magnetic field distribution uniformity is 3%;

[0200] The heat treatment is supplemented by a 0.4 T magnetic field.

[0201] Example 15:

[0202] The only difference from Example 2 is that the plasma spraying is supplemented by a dynamic magnetic field reduction; the dynamic magnetic field reduction includes: a first magnetic field, a second magnetic field, and a third magnetic field that are reduced in sequence. The first magnetic field is maintained for 20% of the plasma spraying time, the second magnetic field is maintained for 60% of the plasma spraying time, and the remaining time is the maintenance time of the third magnetic field. The magnetic field strength of the first magnetic field is 1T, the magnetic field strength of the second magnetic field is 0.8T, and the magnetic field strength of the third magnetic field is 0.5T. The magnetic field distribution uniformity is 1%.

[0203] The heat treatment is supplemented by a 0.5 T magnetic field.

[0204] Example 16:

[0205] The only difference from Example 3 is that the plasma spraying is supplemented by a dynamic magnetic field reduction; the dynamic magnetic field reduction includes: a first magnetic field, a second magnetic field, and a third magnetic field that are reduced in sequence. The first magnetic field is maintained for 22% of the plasma spraying time, the second magnetic field is maintained for 62% of the plasma spraying time, and the remaining time is the maintenance time of the third magnetic field. The magnetic field strength of the first magnetic field is 1.2T, the magnetic field strength of the second magnetic field is 1T, and the magnetic field strength of the third magnetic field is 0.8T. The magnetic field distribution uniformity is 2%.

[0206] The heat treatment is supplemented by a 0.3 T magnetic field.

[0207] Example 17:

[0208] The only difference from Example 8 is that a constant magnetic field with a magnetic field strength of 0.8T is used during plasma spraying.

[0209] Example 18:

[0210] The only difference from Example 8 is that the order of applying the first magnetic field and the third magnetic field is swapped, that is, the third magnetic field, the second magnetic field and the first magnetic field are applied in sequence, and the magnetic field is dynamically increased at this time.

[0211] Example 19:

[0212] The only difference from Example 8 is that the first magnetic field is not provided, and the maintenance time of the first magnetic field is distributed in equal proportion to the second magnetic field and the third magnetic field.

[0213] Example 20:

[0214] The only difference from Example 8 is that the second magnetic field is not provided, and the maintenance time of the second magnetic field is distributed in equal proportion to the first magnetic field and the third magnetic field.

[0215] Example 21:

[0216] The only difference from Example 8 is that the third magnetic field is not provided, and the maintenance time of the third magnetic field is distributed in equal proportion to the first magnetic field and the second magnetic field.

[0217] Example 22:

[0218] The only difference from Example 11 is that the intensity of the magnetic field used during the heat treatment is 0.1T.

[0219] Example 23:

[0220] The only difference from Example 11 is that the intensity of the magnetic field used during the heat treatment is 1T.

[0221] The coatings obtained in Examples 8-23 were subjected to bonding strength tests, mechanical property tests, and high-temperature oxidation resistance tests. The bonding strength of the coatings was obtained using GB / T 8642-2002: "Determination of Bond Strength of Thermal Spray Coatings," and the high-temperature oxidation resistance of the coatings was obtained using ASTM G54. The results are detailed in Table 3 below.

[0222] Table 3

[0223]

[0224] In Table 3, the value-added refers to the increase in mass per unit area of ​​the coating after oxidation at 1000℃ for 100h.

[0225] As can be seen from Tables 1 to 3, the preparation method provided by the present invention adopts a specific preparation process, so that when the FeCoNiMnAl high-entropy alloy powder obtained is used as a raw material for plasma spraying, an FeCoNiMnAl high-entropy alloy coating with excellent performance can be obtained, which is conducive to the preparation of a coating with high mechanical properties, corrosion resistance, and wave absorption properties.

[0226] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the scope of protection of the present invention.

[0227] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0228] In addition, the various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A method for preparing a FeCoNiMnAl high entropy alloy coating, characterized in that: The preparation method comprises: FeCoNiMnAl high entropy alloy powder is used as raw material for plasma spraying, and then heat treatment is performed to obtain FeCoNiMnAl high entropy alloy coating; The preparation process of the FeCoNiMnAl high entropy alloy powder is as follows: mixing a metal precursor powder, a binder and a dispersant to obtain a slurry; spray granulating the slurry to obtain a precursor powder; reducing and sintering the precursor powder to obtain a FeCoNiMnAl high entropy alloy powder; the metal precursor powder is obtained by coprecipitation and calcination; the coprecipitation comprises: mixing a metal salt solution and an ammonium salt solution at a pH value of 8.5-9 to carry out a coprecipitation reaction; the calcination comprises: calcining at 450-550° C. for ≥2 hours in an air atmosphere; the solid content of the slurry is 25-30%; and the holding temperature of the reduction sintering is 1100-1200° C. The plasma spraying is assisted by dynamically reducing the magnetic field; The dynamically reducing magnetic field includes: a first magnetic field, a second magnetic field and a third magnetic field that are reduced in sequence; The first magnetic field is maintained for 20-22% of the plasma spraying time; The second magnetic field is maintained for 60-62% of the plasma spraying time; The magnetic field strength of the first magnetic field is 1-1.2T; the magnetic field strength of the second magnetic field is 0.8-1T; the magnetic field strength of the third magnetic field is 0.5-0.8T; the distribution uniformity of the magnetic field in the dynamically reduced magnetic field is ≤3%; The heat treatment is supplemented with a magnetic field of 0.3-0.5 T; the holding temperature of the heat treatment is 400-600° C.; and the holding time of the heat treatment is ≥1 hour.

2. The preparation method according to claim 1, wherein The atomic ratio of Fe, Co, Ni, Mn and Al in the metal precursor powder is 1:1:1:1:0.5, and the specific surface area is greater than 50m 2 / g; The temperature of the coprecipitation reaction is 60-80°C; The coprecipitation reaction is assisted by stirring at a stirring speed of 400-500 r / min; The aging time of the coprecipitation reaction is ≥2h.

3. The preparation method according to claim 1, wherein The mass percentage of the binder in the slurry is 1-2%; The mass percentage of the dispersant in the slurry is 0.5-1%; The viscosity of the slurry is 200-300 mPa·s; The atomizer speed in the spray granulation is 18000-20000 r / min; The feed rate of the spray granulation is 20-30 mL / min; The feed inlet temperature of the spray granulation is 220-250°C; The discharge port temperature of the spray granulation is 90-100°C.

4. The preparation method according to claim 1, wherein The sintering atmosphere of the reduction sintering includes: hydrogen; The gas flow rate for forming the sintering atmosphere during the reduction sintering is 4-6 L / min; The temperature rise process of the reduction sintering is: when the temperature is less than 600°C, the temperature rise rate is 4-6°C / min; when the temperature is greater than 600°C, the temperature rise rate is 10-12°C / min; The holding time of the reduction sintering is ≥3h; After the reduction sintering, the FeCoNiMnAl high entropy alloy powder is obtained by cooling in the furnace.

5. The preparation method according to claim 1, wherein The FeCoNiMnAl high entropy alloy powder has a Hall flow rate of 22-26s / 50g, an oxygen mass percentage of ≤0.3%, and a sphericity of >90%.

6. The preparation method according to claim 1, wherein The surface roughness Ra of the substrate used in the plasma spraying is 5-7 μm; The FeCoNiMnAl high entropy alloy powder used in the plasma spraying has a D50 particle size of 15-45 μm and a sphericity greater than 90%.

7. The preparation method according to claim 1, wherein The power of the plasma spraying is 35-50kW; The main gas flow rate of the plasma spraying is 40-50SLPM; The auxiliary gas flow rate of the plasma spraying is 10-15 SLPM; The scanning speed of the plasma spraying is 120-180 m / min; The powder feeding rate of the plasma spraying is 20-40 g / min; The distance between the spray gun nozzle and the substrate surface during the plasma spraying is 100-150 mm; The temperature of the substrate surface during the plasma spraying is 50-150°C.

Images