An ultra-high-temperature oxidation-resistant ablation-resistant ceramic coating and a method for preparing the same

Abstract

The application provides an ultrahigh-temperature oxidation-resistant ablation-resistant ceramic coating and a preparation method thereof, and relates to the field of coating processing technology.The application is characterized in that a metal bonding layer, a ceramic inner layer, a ceramic transition layer and a ceramic outer layer are coated on the surface of a substrate in sequence;the thickness of the metal bonding layer is 0.05-0.20 mm;the thickness of the ceramic inner layer is 0.30-0.80 mm;the thickness of the ceramic transition layer is 0.05-0.30 mm;and the thickness of the ceramic outer layer is 0.20-0.80 mm.The raw material powder of the ceramic inner layer, the ceramic transition layer and the ceramic outer layer is subjected to densification treatment through an induction plasma spheroidization technology, and the powder after the densification treatment is sprayed on the substrate by using an atmospheric plasma spraying technology to form a multilayer ceramic coating, so that the high-temperature resistance, oxidation resistance and ablation resistance of the tungsten-copper substrate material are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of coating materials, in particular to a super-high-temperature oxidation-resistant and ablation-resistant ceramic coating and a preparation method thereof. BACKGROUND

[0002] Tungsten-copper alloy material has the characteristics of high melting point, high strength, low thermal expansion coefficient, high electrical conductivity and thermal conductivity, and sweating cooling, and is widely used in aerospace, national defense industry and many civil industrial fields. However, with the sweating and volatilization of copper in the tungsten-copper composite material, tungsten exposed to a high-temperature oxidation environment is severely oxidized and cracked, resulting in a significant decrease in the mechanical properties of the material and a significant decrease in the dimensional stability of the material. Preparing a coating with high-temperature oxidation resistance and ablation resistance on the surface of the tungsten-copper alloy material is one of the effective methods to solve this problem.

[0003] Ceramic materials are considered to be the most promising super-high-temperature protective coating materials due to their high melting point, excellent oxidation and ablation resistance, and other characteristics. Boride ceramics have high melting point, high hardness, high thermal conductivity, good oxidation resistance and thermal shock resistance, and many other advantages, and their oxidation product B2O3 has a low oxygen diffusion coefficient and good self-healing ability, making it one of the most promising thermal protection coating materials, and it has broad application prospects in thermal protection components. However, single-phase boride ceramic coatings have the disadvantages of high brittleness, sensitivity to cracks, and poor reliability.

[0004] By preparing a multi-layer and multi-functional coating on the surface of the tungsten-copper alloy material, oxygen infiltration can be effectively prevented, the oxidation rate of the substrate material can be reduced, and the thermal conductivity of the coating can also be reduced, thereby comprehensively improving the oxidation resistance and ablation resistance of the coating. The addition of SiC in the composite boride ceramic coating forms a glass protective layer under high-temperature oxidation and ablation conditions, thereby improving the thermal stability of the coating, and the oxidation of B2O3 and SiO2 can also form borosilicate glass to inhibit the evaporation of the glass phase and the diffusion of oxygen. In addition, the introduction of oxygen vacancies or lattice distortion and other point defects in the rare earth oxide after ion doping enhances the phonon scattering effect, effectively reduces the thermal conductivity of the sprayed material, and improves the thermal insulation performance of the coating. However, there are still technical difficulties in how to reduce the oxidation failure rate of ceramic materials under super-high-temperature conditions, how to fully utilize the low thermal conductivity of ceramic materials, and how to comprehensively improve the super-high-temperature oxidation resistance and ablation resistance of tungsten-copper composite materials. SUMMARY

[0005] Therefore, the application provides an ultrahigh-temperature oxidation-resistant and ablation-resistant ceramic coating and a preparation method thereof. The application is characterized in that a metal bonding layer, a ceramic inner layer, a ceramic transition layer and a ceramic outer layer are sequentially sprayed on the surface of a tungsten-copper base, wherein the raw material powder of the ceramic inner layer, the ceramic transition layer and the ceramic outer layer is subjected to densification treatment by an induction plasma spheroidization technology, and the powder after the densification treatment is sprayed on the base by an atmospheric plasma spraying technology to form a multilayer ceramic coating, so as to improve the high-temperature resistance, oxidation resistance and ablation resistance of the tungsten-copper composite material.

[0006] The application is implemented by using the following technical scheme:

[0007] An ultrahigh-temperature oxidation-resistant and ablation-resistant ceramic coating, wherein a metal bonding layer, a ceramic inner layer, a ceramic transition layer and a ceramic outer layer are sequentially sprayed on a base.

[0008] The thickness of the metal bonding layer is 0.05-0.20 mm; the thickness of the ceramic inner layer is 0.30-0.80 mm; the thickness of the ceramic transition layer is 0.05-0.30 mm; and the thickness of the ceramic outer layer is 0.20-0.80 mm.

[0009] Preferably, the raw material in the metal bonding layer is one of tungsten powder or tantalum-tungsten alloy powder; the mass percentage of tantalum in the tantalum-tungsten alloy powder is 85%-98%, and the mass percentage of tungsten is 2%-15%.

[0010] Preferably, the raw material powder required for preparing the ceramic inner layer is prepared by the following steps:

[0011] S1-1, ZrO2 and rare earth oxide powder for spraying with a particle size of 20-100 μm are mixed according to a mass ratio of 30-95:5-70 to obtain mixed powder;

[0012] S1-2, the mixed powder is calcined in a high-temperature furnace at 1000-1600 ℃ for 10-80 hours, and the furnace is cooled to room temperature, and the powder is taken out and ball milled for 4-10 hours to less than 5 μm to obtain ball milled powder;

[0013] S1-3, the mixed powder after ball milling in step S1-2 is mixed with water and polyvinyl alcohol to obtain a slurry, wherein the mass ratio of the ball milled powder in the slurry is 30%-50%, and the mass ratio of polyvinyl alcohol in the slurry is 0.2-0.6%;

[0014] S1-4, the slurry is stirred by a ball mill for 0.5-6 hours, and then taken out and subjected to spray drying treatment, and the particles with a particle size of 20-100 μm are obtained after atomization and granulation and sieving, and the process parameters of the spray drying are as follows: the inlet temperature is 200-280 ℃, the outlet temperature is 100-120 ℃, the frequency of a peristaltic pump is 30-50 Hz, and the frequency of an atomization disc is 20-50 Hz.

[0015] S1-5, the particles are subjected to plasma spheroidization treatment, and the raw material powder required for the ceramic inner layer with a particle size of 30-60 μm is obtained by sieving; the process parameters of the plasma spheroidization are as follows: power is 20-30 kW, powder feeding rate is 2-6 RPM, auxiliary gas flow rate is 2-8 L / min, main gas flow rate is 40-60 L / min, carrier gas flow rate is 5-10 L / min, and reaction chamber pressure is 5-16 PSI.

[0016] Further preferably, the rare earth oxide in S1-1 is at least one of Y, La, Ce or Hf oxide.

[0017] Preferably, the raw material powder required for preparing the ceramic transition layer is prepared by the following steps:

[0018] S2-1, ZrB2 powder with a particle size of 1-3 μm, SiC powder with a particle size of 0.5-3 μm, polyvinyl alcohol and deionized water are selected to prepare a mixed slurry; the mass percentage of ZrB2 powder in the mixed slurry is 18%-45%; the mass percentage of SiC powder in the mixed slurry is 3%-20%; and the mass ratio of polyvinyl alcohol in the mixed slurry is 0.3-0.6%;

[0019] S2-2, the mixed slurry is taken out after being ball milled for 0.5-6 hours, and is subjected to spray drying treatment and then atomization granulation, and the ZrB2-SiC agglomerated composite powder with a particle size of 10-100 μm is obtained by sieving; the process parameters of the spray drying are as follows: inlet temperature is 200-380℃, outlet temperature is 100-150℃, peristaltic pump frequency is 30-50 Hz, and atomization disc frequency is 20-50 Hz;

[0020] S2-3, the ZrB2-SiC agglomerated composite powder is subjected to plasma spheroidization treatment, and the raw material powder required for the ceramic transition layer with a particle size of 30-60 μm is obtained by sieving; the process parameters of the plasma spheroidization are as follows: power is 20-30 kW, powder feeding rate is 2-6 RPM, auxiliary gas flow rate is 2-8 L / min, main gas flow rate is 40-60 L / min, carrier gas flow rate is 5-10 L / min, and reaction chamber pressure is 5-16 PSI.

[0021] Preferably, the raw material powder required for the ceramic outer layer is prepared by the following steps:

[0022] S3-1, ZrB2 powder with a particle size of 1-3 μm, silicide powder with a particle size of 0.5-3 μm, HfB2 powder with a particle size of 1-3 μm, polyvinyl alcohol and deionized water are configured into a mixed slurry; the mass percentage of ZrB2 powder in the mixed slurry is 9%-30%, the mass percentage of silicide powder in the mixed slurry is 1.5%-20%, the mass percentage of HfB2 powder in the mixed slurry is 4.5%-12.5%, and the mass percentage of polyvinyl alcohol in the mixed slurry is 0.3-0.5%; more preferably, the silicide powder is SiC powder or SiC-refractory metal silicide powder, and the refractory metal silicide powder is any one or more of ZrSi2, WSi2 or TaSi2.

[0023] S3-2, the mixed slurry is taken out after being ball milled for 0.5-6 hours, and then subjected to spray drying treatment, atomization granulation, and sieving to obtain ZrB2-HfB2-silicide agglomerated composite powder with a particle size of 10-100 μm; the process parameters of the spray drying are as follows: the inlet temperature is 200-380 ℃, the outlet temperature is 100-150 ℃, the frequency of the peristaltic pump is 30-50 Hz, and the frequency of the atomization disc is 20-50 Hz.

[0024] S3-3, the ZrB2-HfB2-silicide agglomerated composite powder is subjected to plasma spheroidization treatment, and sieving is performed to obtain raw material powder required for a ceramic outer layer with a particle size of 30-60 μm; the process parameters of the plasma spheroidization are as follows: the power is 20-30 kW, the powder feeding rate is 2-6 RPM, the auxiliary gas flow rate is 2-8 L / min, the main gas flow rate is 40-60 L / min, the carrier gas flow rate is 5-10 L / min, and the reaction chamber pressure is 5-16 PSI.

[0025] The application further provides a preparation method of the super-high-temperature oxidation-resistant ablation-resistant ceramic coating, comprising the following steps:

[0026] S1, pretreatment of the base material:

[0027] The tungsten-copper base material is subjected to cleaning treatment, and then subjected to sand blasting roughening treatment by using diamond sand, wherein the pressure is controlled to be 0.1-0.5 MPa, the sand blasting distance is 30-120 μm, and the sand blasting time is 3-10 min;

[0028] S2, spraying of the metal bonding layer:

[0029] The raw material powder of the metal bonding layer is weighed according to the proportion, and then subjected to atmospheric plasma spraying on the surface of the pretreated tungsten-copper alloy base material to form the metal bonding layer;

[0030] S3, spraying of the ceramic inner layer:

[0031] The raw material powder of the ceramic inner layer is weighed in proportion, and atmospheric plasma spraying is performed on the surface of the metal bonding layer to form the ceramic inner layer;

[0032] S4, spraying a ceramic transition layer:

[0033] The raw material powder of the ceramic transition layer is weighed in proportion, and atmospheric plasma spraying is performed on the surface of the ceramic inner layer to form the ceramic transition layer;

[0034] S5, spraying a ceramic outer layer:

[0035] The raw material powder of the ceramic outer layer is weighed in proportion, and atmospheric plasma spraying is performed on the surface of the ceramic transition layer to form the ceramic outer layer.

[0036] Preferably, step S1 is to clean the surface of the tungsten-copper alloy substrate with acetone.

[0037] Preferably, the particle size of the diamond sand in step S1 is 60-100 mu m.

[0038] Preferably, in steps S2, S3, S4 and S5, the spraying current is 500A-1000A, the main gas Ar flow rate is 40L / min-80L / min, the auxiliary gas H2 flow rate is 1L / min-10L / min, the carrier gas Ar flow rate is 1L / min-10L / min, the powder feeding rate is 10%-30%, and the spraying distance is 70mm-120mm.

[0039] Compared with the prior art, the present application has the following beneficial effects:

[0040] 1. In the present application, ZrB2 has high melting point, high stability, good thermal shock resistance and oxidation resistance, and is the material with the highest content in the ceramic outer layer, so that the ceramic outer layer has good ablation resistance; SiC generates a SiO2-based protective layer during oxidation, which inhibits oxygen diffusion and seals part of the coating defects, thereby improving the stability of the coating; HfB2 has high melting point, high thermal conductivity and other characteristics, and the HfO2 generated under the action of ultra-high temperature oxidation and ablation can form a dense oxide layer structure with ZrO2, effectively slowing down the penetration of oxygen; according to different requirements of tungsten-copper composite materials for oxidation resistance, ablation resistance and erosion resistance, the corresponding rare earth silicide can be selected; the rare earth oxide doped zirconia has excellent heat insulation performance and can effectively improve the ablation resistance of the composite coating; the metal bonding layer is composed of W or Ta-W, which can maintain the stability of the bonding layer and the interface between the tungsten-copper substrate, and maintain the sweating behavior of the copper phase by adjusting the porosity of the coating.

[0041] 2. The raw materials for the ceramic inner layer, the ceramic transition layer and the ceramic outer layer are densified by using the inductive plasma spheroidization technology in the present application. The high temperature generated by the plasma is used to consume the binder in the polymerized powder, and the powder particles are heated and condensed into spherical droplets, so as to reduce the internal pores of the agglomerated composite powder particles, increase the cohesive strength and density of the agglomerated composite powder particles, and improve the fluidity and bulk density of the agglomerated composite powder. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 Figure 6 is a surface scanning electron microscope image of the ZrB2-SiC powder after plasma spheroidization in Example 1;

[0043] Figure 2 Figure 7 is a cross-sectional scanning electron microscope image of the ZrB2-SiC powder after plasma spheroidization in Example 1;

[0044] Figure 3 Figure 8 is a cross-sectional scanning electron microscope image of the ceramic coating prepared in Example 1;

[0045] Figure 4 Figure 9 is a surface scanning electron microscope image of the ceramic coating prepared in Example 1 after high-temperature ablation;

[0046] Figure 5 Figure 10 is a surface morphology of the tungsten-copper composite material with a ceramic coating prepared in Example 2 after ablation. DETAILED DESCRIPTION

[0047] The present application will be further described below in combination with examples.

[0048] Example 1

[0049] A preparation method of an ultra-high-temperature oxidation-resistant and ablation-resistant ceramic coating, and the specific steps are as follows:

[0050] S1, pretreatment of the tungsten-copper alloy substrate:

[0051] The tungsten-copper alloy substrate is cleaned with acetone to remove oil stains on the surface of the substrate, and then sandblasting roughening treatment is performed using diamond sand (particle size of 50 μm), wherein the pressure is controlled to be 0.5 MPa, the sandblasting distance is 70 μm, and the sandblasting time is 3 min;

[0052] S2, spraying a metal bonding layer: tungsten powder is sprayed on the surface of the pretreated tungsten-copper alloy substrate by atmospheric plasma spraying to form a metal bonding layer with a thickness of 0.12 mm, wherein the spraying current is 550 A, the main gas Ar flow rate is 70 L / min, the auxiliary gas H2 flow rate is 5 L / min, the carrier gas Ar flow rate is 4 L / min, the powder feeding rate is 15%, and the spraying distance is 100 mm;

[0053] S3, spraying ceramic inner layer:

[0054] S3-1, preparing raw material powder of ceramic inner layer, the specific steps are as follows:

[0055] (1) selecting ZrO2 and rare earth oxide Y2O3 powder for spraying with particle size of 20-100 μm, mixing according to mass ratio of 43:7 to obtain mixed powder;

[0056] (2) calcining the mixed powder in a high-temperature furnace at 1500 ℃ for 12 hours, cooling to room temperature with the furnace, and taking out the powder to ball mill for 8 hours to obtain ball-milled powder;

[0057] (3) mixing the ball-milled mixed powder in step (2) with water and polyvinyl alcohol to obtain a slurry, the mass ratio of the ball-milled powder in the slurry is 49.9%; the mass ratio of polyvinyl alcohol in the slurry is 0.2%; (4) performing spray drying treatment on the slurry, and finally atomizing and granulating to obtain particles with particle size of 5 μm after sieving, the process parameters of spray drying are: inlet temperature is 240 ℃, outlet temperature is 100 ℃, frequency of peristaltic pump is 30 Hz, and frequency of atomizing disc is 30 Hz;

[0058] (5) performing plasma spheroidization treatment on the particles, and sieving to obtain raw material powder required for the ceramic inner layer with particle size of 30-60 μm; the process parameters of plasma spheroidization are as follows: power is 30 kW, powder feeding rate is 3 RPM, auxiliary gas flow rate is 4 L / min, main gas flow rate is 50 L / min, carrier gas flow rate is 6 L / min, and reaction chamber pressure is 10 PSI;

[0059] S3-2, performing atmospheric plasma spraying on the raw material powder of the ceramic inner layer on the surface of the metal bonding layer to form a ceramic inner layer with thickness of 0.55 mm; wherein the spraying current is 650 A, the main gas Ar flow rate is 50 L / min, the auxiliary gas H2 flow rate is 5 L / min, the carrier gas Ar flow rate is 4 L / min, the powder feeding rate is 20%, and the spraying distance is 100 mm;

[0060] S4, spraying ceramic transition layer:

[0061] S4-1, preparing raw material powder of ceramic transition layer, the specific steps are as follows:

[0062] (1) selecting ZrB2 powder with particle size of 1-3 μm, SiC powder with particle size of 0.5-3 μm, polyvinyl alcohol and deionized water to configure into a mixed slurry; the mass percentage of ZrB2 powder in the mixed slurry is 34.74%; the mass percentage of SiC powder in the mixed slurry is 5.19%; and the mass ratio of polyvinyl alcohol in the mixed slurry is 0.3%;

[0063] (2) the mixed slurry is taken out after ball milling for 4 hours, and then is subjected to spray drying treatment, atomization granulation, and sieving to obtain ZrB2-SiC agglomerated composite powder with a particle size of 10-100 μm; the process parameters of the spray drying are as follows: an inlet temperature of 300°C, an outlet temperature of 100°C, a peristaltic pump frequency of 45 Hz, and an atomization disc frequency of 30 Hz;

[0064] (3) the ZrB2-SiC agglomerated composite powder is subjected to plasma spheroidization treatment to obtain raw material powder for a ceramic transition layer, i.e., ZrB2-SiC plasma spheroidized powder, with a particle size of 30-60 μm; the process parameters of the plasma spheroidization are as follows: a power of 30 kW, a powder feeding rate of 3 RPM, an auxiliary gas flow rate of 8 L / min, a main gas flow rate of 60 L / min, a carrier gas flow rate of 10 L / min, and a reaction chamber pressure of 10 PSI.

[0065] S4-2, the raw material powder for the ceramic transition layer is subjected to atmospheric plasma spraying on the surface of the ceramic inner layer to form a ceramic transition layer with a thickness of 0.16 mm; the spraying current is 580 A, the main gas Ar flow rate is 45 L / min, the auxiliary gas H2 flow rate is 5 L / min, the carrier gas Ar flow rate is 4 L / min, the powder feeding rate is 20%, and the spraying distance is 100 mm;

[0066] S5, preparing a ceramic outer layer:

[0067] S5-1, preparing raw material powder for the ceramic outer layer:

[0068] (1) ZrB2 powder with a particle size of 1-3 μm, SiC powder with a particle size of 0.5-3 μm, HfB2 powder with a particle size of 1-3 μm, polyvinyl alcohol, and deionized water are configured into a mixed slurry; the mass percentage of the ZrB2 powder in the mixed slurry is 20.7%, the mass percentage of the SiC powder in the mixed slurry is 4.4%, the mass percentage of the HfB2 powder in the mixed slurry is 14.8%, and the mass percentage of the polyvinyl alcohol in the mixed slurry is 0.3%;

[0069] (2) the mixed slurry is taken out after ball milling for 4 hours, and then is subjected to spray drying treatment, atomization granulation, and sieving to obtain ZrB2-SiC-HfB2 agglomerated composite powder with a particle size of 10-100 μm; the process parameters of the spray drying are as follows: an inlet temperature of 300°C, an outlet temperature of 100°C, a peristaltic pump frequency of 45 Hz, and an atomization disc frequency of 30 Hz;

[0070] (3) The ZrB2-SiC-HfB2 agglomerated composite powder is subjected to plasma spheroidization treatment, and sieving is performed to obtain raw material powder required for the ceramic outer layer with a size of 30-60 μm; the process parameters of the plasma spheroidization are as follows: power is 30 kW, powder feeding rate is 2 RPM, auxiliary gas flow rate is 8 L / min, main gas flow rate is 60 L / min, carrier gas flow rate is 10 L / min, and reaction chamber pressure is 10 PSI.

[0071] S5-2, the raw material powder of the ceramic outer layer is subjected to atmospheric plasma spraying on the surface of the ceramic transition layer to form a ceramic outer layer with a thickness of 0.80 mm; wherein the spraying current is 900 A, the main gas Ar flow rate is 70 L / min, the auxiliary gas H2 flow rate is 10 L / min, the carrier gas Ar flow rate is 10 L / min, the powder feeding rate is 20%, and the spraying distance is 100 mm.

[0072] Example 2

[0073] A preparation method of an ultra-high-temperature oxidation-resistant ablation-resistant ceramic coating, and the specific steps are as follows:

[0074] S1, pretreatment of the tungsten-copper alloy substrate:

[0075] The tungsten-copper alloy substrate is cleaned with acetone to remove oil stains on the surface of the substrate; then sand blasting roughening treatment is performed with diamond sand with a particle size of 50 μm, wherein the pressure is controlled to be 0.5 MPa, the sand blasting distance is 70 μm, and the sand blasting time is 3 min;

[0076] S2, spraying a metal bonding layer: Ta10W alloy powder is subjected to atmospheric plasma spraying on the surface of the pretreated tungsten-copper alloy substrate to form a metal bonding layer with a thickness of 0.2 mm; wherein the spraying current is 550 A, the main gas Ar flow rate is 60 L / min, the auxiliary gas H2 flow rate is 1.5 L / min, the carrier gas Ar flow rate is 4 L / min, the powder feeding rate is 15%, and the spraying distance is 100 mm;

[0077] S3, spraying a ceramic inner layer:

[0078] S3-1, preparation of raw material powder for the ceramic inner layer, and the specific steps are as follows:

[0079] (1) ZrO2 and La2O3 powders with a particle size of 20-100 μm for spraying are mixed in a mass ratio of 88:12 to obtain a mixed powder;

[0080] (2) The mixed powder is calcined in a high-temperature furnace at 1500°C for 12 hours, and the furnace is cooled to room temperature; the powder is taken out and ball milled for 8 hours to below 5 μm to obtain a ball milled powder;

[0081] (3) mixing the mixed powder after ball milling in step (2) with water and polyvinyl alcohol to obtain a slurry, the mass ratio of the ball-milled powder in the slurry being 49.9%; the mass ratio of polyvinyl alcohol in the slurry being 0.2%;

[0082] (4) performing spray drying treatment on the slurry, and sieving the granules after final atomization and granulation to obtain granules with a particle size of 20-100 μm, the process parameters for spray drying being an inlet temperature of 240°C, an outlet temperature of 100°C, a peristaltic pump frequency of 30 Hz, and an atomization disc frequency of 30 Hz;

[0083] (5) performing plasma spheroidization treatment on the granules, and sieving to obtain raw material powder for a ceramic inner layer with a particle size of 30-60 μm; the process parameters for plasma spheroidization being a power of 30 kW, a powder feeding rate of 3 RPM, an auxiliary gas flow rate of 4 L / min, a main gas flow rate of 50 L / min, a carrier gas flow rate of 6 L / min, and a reaction chamber pressure of 10 PSI.

[0084] S3-2, performing atmospheric plasma spraying on the raw material powder of the ceramic inner layer on the surface of the metal bonding layer to form a ceramic inner layer with a thickness of 0.5 mm; wherein the spraying current is 650 A, the main gas Ar flow rate is 50 L / min, the auxiliary gas H2 flow rate is 7 L / min, the carrier gas Ar flow rate is 4 L / min, the powder feeding rate is 20%, and the spraying distance is 100 mm;

[0085] S4, preparing a ceramic transition layer:

[0086] S4-1, preparing raw material powder for the ceramic transition layer, the specific steps being as follows:

[0087] (1) selecting ZrB2 powder with a particle size of 1-3 μm, SiC powder with a particle size of 0.5-3 μm, polyvinyl alcohol, and deionized water to configure a mixed slurry; the mass ratio of ZrB2 powder in the mixed slurry being 34.74%; the mass ratio of SiC powder in the mixed slurry being 5.19%; the mass ratio of polyvinyl alcohol in the mixed slurry being 0.3%;

[0088] (2) taking out the mixed slurry after ball milling for 4 hours, performing spray drying treatment, atomization and granulation, and sieving to obtain ZrB2-SiC agglomerated composite powder with a particle size of 10-100 μm, i.e. ZrB2-SiC plasma spheroidized powder; the process parameters for spray drying being an inlet temperature of 300°C, an outlet temperature of 100°C, a peristaltic pump frequency of 45 Hz, and an atomization disc frequency of 30 Hz;

[0089] (3) the ZrB2-SiC-HfB2-TaSi2 agglomerated composite powder is subjected to plasma spheroidization treatment, and the raw material powder required for the ceramic outer layer with a particle size of 30-60 μm is obtained after sieving; the process parameters of the plasma spheroidization are as follows: power is 30 kW, powder feeding rate is 3 RPM, auxiliary gas flow is 8 L / min, main gas flow is 60 L / min, carrier gas flow is 8 L / min, and reaction chamber pressure is 12 PSI.

[0090] S4-2, the raw material powder of the ceramic transition layer is subjected to atmospheric plasma spraying on the surface of the ceramic inner layer to form a ceramic transition layer with a thickness of 0.15 mm; wherein the spraying current is 580 A, the main gas Ar flow is 45 L / min, the auxiliary gas H2 flow is 5 L / min, the carrier gas Ar flow is 4 L / min, the powder feeding rate is 20%, and the spraying distance is 100 mm;

[0091] S5, preparing a ceramic outer layer:

[0092] S5-1, preparing a raw material powder for the ceramic outer layer:

[0093] (1) selecting ZrB2 powder with a particle size of 1-3 μm, SiC powder with a particle size of 0.5-3 μm, HfB2 powder with a particle size of 1-3 μm, TaSi2 powder with a particle size of 0.5-3 μm, polyvinyl alcohol, and deionized water to configure a mixed slurry; the mass percentage of ZrB2 powder in the mixed slurry is 18%, the mass percentage of SiC powder in the mixed slurry is 4%, the mass percentage of HfB2 powder in the mixed slurry is 12.4%, and the mass percentage of TaSi2 powder in the mixed slurry is 5.6%; the mass percentage of polyvinyl alcohol in the mixed slurry is 0.3%;

[0094] (2) after the mixed slurry is ball milled for 4 hours, it is taken out, subjected to spray drying treatment, atomized and granulated, and sieved to obtain ZrB2-SiC-HfB2-TaSi2 agglomerated composite powder with a particle size of 10-100 μm; the process parameters of the spray drying are as follows: inlet temperature is 300°C, outlet temperature is 100°C, peristaltic pump frequency is 45 Hz, and atomizing disc frequency is 30 Hz;

[0095] (3) the ZrB2-SiC-HfB2-TaSi2 agglomerated composite powder is subjected to plasma spheroidization treatment, and the raw material powder required for the ceramic outer layer with a particle size of 30-60 μm is obtained after sieving; the process parameters of the plasma spheroidization are as follows: power is 30 kW, powder feeding rate is 3 RPM, auxiliary gas flow is 8 L / min, main gas flow is 60 L / min, carrier gas flow is 8 L / min, and reaction chamber pressure is 12 PSI.

[0096] S5-2, the raw material powder of the ceramic outer layer is sprayed on the surface of the ceramic transition layer by atmospheric plasma spraying to form a ceramic outer layer with a thickness of 0.80 mm. The spraying current is 950 A, the main gas Ar flow rate is 50 L / min, the auxiliary gas H2 flow rate is 10 L / min, the carrier gas Ar flow rate is 10 L / min, the powder feeding rate is 15%, and the spraying distance is 100 mm.

[0097] The above only describes the preferred embodiments of the present application, and it should be noted that those skilled in the art can make several improvements and refinements without departing from the principles of the present application, and these improvements and refinements should also be considered within the scope of protection of the present application.

Claims

1. A high-temperature oxidation-resistant and ablation-resistant ceramic coating, characterized in that, A metal bonding layer, a ceramic inner layer, a ceramic transition layer, and a ceramic outer layer are sequentially coated on the substrate surface. The thickness of the metal bonding layer is 0.05~0.20mm; the thickness of the inner ceramic layer is 0.30~0.80mm; the thickness of the ceramic transition layer is 0.05~0.30mm; and the thickness of the outer ceramic layer is 0.20~0.80mm. The raw material powder required for preparing the ceramic inner layer is prepared by the following steps: S1-1. Select ZrO2 for spraying with a particle size of 20~100μm and rare earth oxide powder and mix them at a mass ratio of 30~95:5~70 to obtain a mixed powder; S1-2. The mixed powder is calcined in a high-temperature furnace at 1000℃~1600℃ for 10~80 hours, cooled to room temperature with the furnace, and the powder is taken out and ball-milled for 4~10 hours to below 5μm to obtain ball-milled powder. S1-3. The ball-milled powder from step S1-2 is mixed with water and polyacrylamide to obtain a slurry. The mass ratio of the ball-milled powder in the slurry is 30%~50%, and the mass ratio of polyacrylamide in the slurry is 0.2%~0.6%. S1-4. The slurry is stirred in a ball mill for 0.5h to 6h and then taken out and spray dried. After atomization and granulation, it is sieved to obtain particles with a particle size of 20 to 100μm. The process parameters for spray drying are: inlet temperature of 200 to 280℃, outlet temperature of 100 to 120℃, peristaltic pump frequency of 30 to 50Hz, and atomizing disc frequency of 20 to 50Hz. S1-5. The particles are subjected to plasma spheroidization treatment and sieved to obtain the raw material powder required for the ceramic inner layer with a diameter of 30~60μm. The process parameters of plasma spheroidization are as follows: power of 20~30kW, powder feeding rate of 2~6RPM, auxiliary gas flow rate of 2~8 L / min, main gas flow rate of 40~60 L / min, carrier gas flow rate of 5~10 L / min, and reaction chamber pressure of 5~16PSI. The raw material powder required for preparing the ceramic transition layer is prepared by the following steps: S2-1. A mixed slurry is prepared by selecting ZrB2 powder with a particle size of 1~3μm, SiC powder with a particle size of 0.5~3μm, polyacrylamide, and deionized water; the mass percentage of ZrB2 powder in the mixed slurry is 18%~45%; the mass percentage of SiC powder in the mixed slurry is 3%~20%; and the mass percentage of polyacrylamide in the mixed slurry is 0.3~0.6%. S2-2. After ball milling the mixed slurry for 0.5 to 6 hours, remove it, spray dry it, and then atomize and granulate it. After sieving, ZrB2-SiC agglomerated composite powder with a particle size of 10 to 100 μm is obtained. The process parameters of the spray drying are: inlet temperature of 200 to 380℃, outlet temperature of 100 to 150℃, peristaltic pump frequency of 30 to 50 Hz, and atomizing disc frequency of 20 to 50 Hz. S2-3. The ZrB2-SiC agglomerated composite powder is subjected to plasma spheroidization treatment and sieved to obtain the raw material powder required for the ceramic transition layer with a thickness of 30~60μm. The process parameters of the plasma spheroidization are as follows: power of 20~30kW, powder feeding rate of 2~6RPM, auxiliary gas flow rate of 2~8 L / min, main gas flow rate of 40~60 L / min, carrier gas flow rate of 5~10 L / min, and reaction chamber pressure of 5~16PSI. The raw material powder required for the ceramic outer layer is prepared by the following steps: S3-1. A mixed slurry is prepared by selecting ZrB2 powder with a particle size of 1~3μm, silica powder with a particle size of 0.5~3μm, HfB2 powder with a particle size of 1~3μm, polyacrylamide, and deionized water; the mass percentage of ZrB2 powder in the mixed slurry is 9%~30%, the mass percentage of silica powder is 1.5%~20%, the mass percentage of HfB2 powder is 4.5%~12.5%, and the mass percentage of polyacrylamide is 0.3%~0.5%. S3-2. After ball milling the mixed slurry for 0.5 to 6 hours, remove it, spray dry it, and then atomize and granulate it. After sieving, ZrB2-HfB2-silicide agglomerated composite powder with a particle size of 10 to 100 μm is obtained. The process parameters of the spray drying are: inlet temperature of 200 to 380℃, outlet temperature of 100 to 150℃, peristaltic pump frequency of 30 to 50 Hz, and atomizing disc frequency of 20 to 50 Hz. S3-3. The ZrB2-HfB2-silicide agglomerated composite powder is subjected to plasma spheroidization treatment and sieved to obtain the raw material powder required for the ceramic outer layer with a thickness of 30~60μm. The process parameters of the plasma spheroidization are as follows: power of 20~30kW, powder feeding rate of 2~6RPM, auxiliary gas flow rate of 2~8 L / min, main gas flow rate of 40~60 L / min, carrier gas flow rate of 5~10 L / min, and reaction chamber pressure of 5~16PSI.

2. The ultra-high temperature anti-oxidation and ablation-resistant ceramic coating according to claim 1, characterized in that, The raw material in the metal bonding layer is either tungsten powder or tantalum-tungsten alloy powder; the tantalum-tungsten alloy powder contains 85% to 98% tantalum by mass and 2% to 15% tungsten by mass.

3. The ultra-high temperature anti-oxidation and ablation-resistant ceramic coating according to claim 1, characterized in that, The rare earth oxide is at least one oxide of Y, La, Ce or Hf.

4. The ultra-high temperature anti-oxidation and ablation-resistant ceramic coating according to claim 1, characterized in that, The silicide powder in step S3-1 is SiC powder or SiC-refractory metal silicide powder, wherein the refractory metal silicide powder is any one or more of ZrSi2, WSi2 or TaSi2.

5. The method for preparing the ultra-high temperature antioxidant and ablation-resistant ceramic coating according to any one of claims 1 to 4, characterized in that, Includes the following steps: S1. Pretreatment of matrix material: The tungsten copper matrix material is cleaned and then roughened by sandblasting with diamond sand. The pressure is controlled at 0.1~0.5MPa, the sandblasting distance is 30~120μm, and the sandblasting time is 3~10min. S2, Spraying metal bonding layer: Weigh the raw material powder of the metal bonding layer according to the proportion, and perform atmospheric plasma spraying on the surface of the pretreated tungsten copper alloy substrate to form a metal bonding layer. S3, Apply ceramic inner layer: Weigh the raw material powder of the ceramic inner layer according to the proportion, and perform atmospheric plasma spraying on the surface of the metal bonding layer to form the ceramic inner layer. S4. Apply ceramic transition layer: Weigh the raw material powder for the ceramic transition layer according to the specified ratio, and perform atmospheric plasma spraying on the surface of the inner ceramic layer to form the ceramic transition layer. S5. Spraying ceramic outer layer: Weigh the raw material powder for the ceramic outer layer according to the specified ratio, and perform atmospheric plasma spraying on the surface of the ceramic transition layer to form the ceramic outer layer.

6. The preparation method according to claim 5, characterized in that, Step S1 involves cleaning the surface of the tungsten-copper alloy substrate with acetone; the diamond abrasive in step S1 has a particle size of 60~100μm.

7. The preparation method according to claim 5, characterized in that, In steps S2, S3, S4, and S5, the spraying current is 500A~1000A, the main gas Ar flow rate is 40L / min~80L / min, the auxiliary gas H2 flow rate is 1L / min~10L / min, the carrier gas Ar flow rate is 1L / min~10L / min, the powder feeding rate is 10%~30%, and the spraying distance is 70mm~120mm.

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