Thermal protection coating as well as preparation method and application thereof

Abstract

The invention provides a thermal protection coating as well as a preparation method and application thereof. The thermal protection coating comprises a NiCoCrAlY first bonding layer, a NiCoCrAlY second bonding layer, a CeYSZ first ceramic layer and a GdYbYSZ second ceramic layer which are sequentially arranged on the surface of a base material, and the second NiCoCrAlY bonding layer is made of CeO2 (CeO2) and Al2O3 (Al2O3). According to the invention, a thermal protection coating structure with double bonding layers and double ceramic layers is constructed on the surface of the base material, and CeO2 and Al2O3 nano-particle reinforced phases are introduced, so that the use temperature of the thermal protection coating is increased, and the thermal strain tolerance, the crack resistance and the oxidation resistance are greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of metal surface treatment, in particular to the technical field of high-temperature thermal protective coatings, and in particular to a thermal protective layer and a preparation method and application thereof. Background Art

[0002] The inner wall of the engine combustion chamber faces extreme conditions of high temperature, high pressure and erosion. Taking a typical rotating detonation engine as an example, when working, the inner wall of the combustion chamber faces ablation of about 2000K high-temperature gas, and there are effects such as instantaneous temperature rise, large heat flux density, uneven heat distribution and pulse shock inside the combustion chamber, which have a strong thermal erosion effect on the inner wall of the combustion chamber. The existing technology mainly uses active cooling methods such as film cooling and pipeline water cooling for cooling, but the active cooling pipeline is complex, costly and difficult to maintain. Therefore, it is of great significance to prepare a thermal protective coating with low thermal conductivity, high bonding strength and high temperature erosion resistance on the inner wall of the engine combustion chamber that has similar working conditions to the typical rotating detonation engine.

[0003] Yttria-stabilized zirconia (YSZ) coating is the most commonly used and mature thermal barrier coating material. However, when the surface temperature of the YSZ thermal barrier coating exceeds 1200°C for a long time, the ceramic coating gradually densifies, causing the thermal conductivity to increase, and a large amount of thermally grown oxide (TGO) is generated at the metal bonding layer interface, resulting in degradation of the mechanical and thermal properties of the coating, and peeling due to stress adaptation problems. In addition, the engine combustion chamber has a small-sized internal pore structure, and spraying the coating on the inner wall of the combustion chamber has problems such as difficult jet control, large dust pollution, and uneven coating.

[0004] CN110144554A discloses a method for preparing a NiCrAlY / YSZ / laser modified YSZ thermal barrier coating on a high temperature alloy surface, comprising: preparing a NiCrAlY bonding layer on a cleaned high temperature alloy substrate by electron beam physical vapor deposition; preparing a YSZ ceramic layer on the NiCrAlY bonding layer by electron beam physical vapor deposition; laser remelting and modifying the surface of the YSZ ceramic layer to obtain a NiCrAlY / YSZ / laser modified YSZ thermal barrier coating. This technology reduces the diffusion of harmful gases, improves the high temperature oxidation resistance of the thermal barrier coating, and prolongs the service life of the thermal barrier coating by obtaining a YSZ / laser modified YSZ composite structure with a dense microstructure.

[0005] CN109207917A discloses a NiCrAlSi / CeO2 doped YSZ thermal barrier coating, which includes a CeO2 doped YSZ deposition layer, a NiCrAlSi bonding layer and a nickel-based high-temperature alloy layer from top to bottom. A peak array microstructure is formed at the junction of the NiCrAlSi bonding layer and the nickel-based high-temperature alloy layer, which increases the contact area between the NiCrAlSi bonding layer and the substrate, forms a micromechanical interlock, and improves the bonding strength between the NiCrAlSi bonding layer and the substrate. The concave and convex surfaces of the peak array microstructure can effectively prevent cracks from expanding at the interface under the action of the binding mechanism, making the coating more solid.

[0006] CN115449786A discloses a thermal barrier coating, comprising a YSZ base layer and a YSZ surface layer, wherein the YSZ base layer has a Y2O3 content of 6-8wt.%, and an Al2O3 content of 5-10wt.%; the YSZ surface layer has a Y2O3 content of 10-12wt.%, and an Al2O3 content of 5-10wt.%. The present invention can improve the Young's modulus, bending strength and fracture toughness of the YSZ base layer and the YSZ surface layer by limiting the content of dispersed phase Al2O3 and stabilizer Y2O3 in the YSZ base layer and the YSZ surface layer; at the same time, the structure of the YSZ surface layer is appropriately improved to improve the phase stability of ZrO2. This technology effectively improves the elastic modulus, fracture toughness and other defects of the thermal barrier coating.

[0007] In order to meet the thermal protection needs of engine nozzles with high heat, strong erosion and uneven temperature, it is of great significance to provide a thermal protection coating with higher temperature bearing capacity, better heat resistance, and better anti-erosion and anti-corrosion properties. Summary of the invention

[0008] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a thermal protective coating and a preparation method thereof. The present invention constructs a thermal protective coating structure with a double bonding layer and a double ceramic layer on the surface of the substrate, thereby improving the use temperature and thermal strain tolerance of the thermal protective coating, effectively preventing the problem of thermal protective coating peeling, so that each layer of coating can give full play to the material's superior performance and avoid inferior performance, and by introducing a nanoparticle reinforcement phase in the second bonding layer of NiCoCrAlY, the coating's crack resistance and oxidation resistance are greatly improved by utilizing the dispersion strengthening effect.

[0009] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0010] In a first aspect, the present invention provides a thermal protective coating, the thermal protective coating comprising a NiCoCrAlY first bonding layer, a NiCoCrAlY second bonding layer, a CeYSZ first ceramic layer and a GdYbYSZ second ceramic layer sequentially disposed on a surface of a substrate;

[0011] The material of the NiCoCrAlY second bonding layer includes NiCoCrAlY metal ceramic composite powder;

[0012] The NiCoCrAlY metal ceramic composite powder includes CeO2 and Al2O3.

[0013] The present invention introduces CeO2 and Al2O3 nanoparticle reinforcement phases into the NiCoCrAlY second bonding layer, which can hinder the generation of spinel oxides, effectively inhibit the generation of cracks, and prevent the expansion of cracks. The addition of CeO2 can inhibit the oxidation of the coating and improve the coating's antioxidant capacity. The GdYbYSZ second ceramic layer with stronger corrosion resistance and sintering resistance is used as the ceramic surface layer to improve the stability and corrosion resistance of the coating at high temperatures. The present invention improves the use temperature and thermal strain tolerance of the coating by constructing a coating structure of a double-layer bonding layer and a double-layer ceramic layer, effectively preventing the problem of coating peeling, so that each layer of coating can give full play to the material's superior performance and avoid inferior performance.

[0014] In the present invention, the thermal expansion coefficient of the NiCoCrAlY first bonding layer is 17×10 -6 / ℃-18×10 -6 / ℃, the thermal expansion coefficient of the second NiCoCrAlY bonding layer is 15×10 -6 / ℃-17×10 -6 / ℃, the thermal expansion coefficient of the first CeYSZ ceramic layer is 11×10 -6 / ℃-13×10 -6 / ℃, the thermal expansion coefficient of the second ceramic layer of GdYbYSZ is 9×10 -6 / ℃-11×10 -6 / ℃.

[0015] The present invention uses a CeYSZ first ceramic layer whose thermal expansion coefficient is closer to that of the NiCoCrAlY second bonding layer, which alleviates the stress mismatch problem caused by the large difference in thermal expansion coefficients. In addition, the dense structure of CeYSZ can block the diffusion of oxygen elements, inhibit the growth of TGO, and alleviate the problem of coating peeling during alternating thermal cycles, thereby improving the thermal shock resistance of the coating. The present invention constructs a coating structure with a layer-by-layer decreasing thermal expansion coefficient on the surface of the substrate, thereby increasing the use temperature and thermal strain tolerance of the coating, effectively preventing the coating from peeling off, and allowing each layer of the coating to give full play to the material's superior performance and avoid inferior performance.

[0016] In the NiCoCrAlY first bonding layer and the NiCoCrAlY second bonding layer, Co can improve the toughness and fatigue resistance of the bonding layer. If Co is too much, the oxidation resistance of the bonding layer will decrease and the hardness will decrease. If Co is too little, it will be unfavorable to improve the toughness of the bonding layer; Cr can improve the thermal corrosion resistance of the bonding layer. If Cr is too little, it will be unfavorable to improve the thermal corrosion resistance. If Cr is too much, the oxidation resistance of the coating will decrease; Al can improve the oxidation resistance of the bonding layer. If Al is too little, the oxidation resistance improvement is not ideal. If Al is too much, the mechanical properties will decrease and the thermal expansion coefficient will decrease; Y can promote the formation of a good bonding interface between the bonding layer and other layers, and improve the corrosion resistance and thermal shock resistance of the bonding layer. If Y is too little, it will be unfavorable to improve the thermal shock resistance of the coating. If Y is too much, it will increase the cost and reduce the mechanical properties; Ni can improve the oxidation resistance and fatigue resistance of the NiCoCrAlY first bonding layer.

[0017] Preferably, the NiCoCrAlY first bonding layer includes, by mass percentage, Co: 20%-26%, Cr: 15%-19%, Al: 11.5%-13.5%, Y: 0.2%-0.7%, and the balance is Ni.

[0018] The present invention increases the Al content in the first NiCoCrAlY bonding layer to 11.5%-13.5%. When applied to high temperature and high pressure conditions, sufficient Al preferentially generates alumina TGO to prevent the generation of cobalt oxide or chromium oxide with a spinel structure, which causes cracks in the coating, leading to degradation of the mechanical and thermal properties of the coating, and causing the coating to fall off from the substrate due to stress mismatch problems. If Al is too little, it is not conducive to improving the anti-oxidation performance, and if Al is too much, it will lead to a decrease in mechanical properties and a decrease in thermal expansion coefficient.

[0019] In the NiCoCrAlY first bonding layer, the mass percentage of Co is 20%-26%, for example, it can be 20%, 21%, 22%, 23%, 24%, 25% or 26%, the mass percentage of Cr is 15%-19%, for example, it can be 15%, 16%, 17%, 18% or 19%, the mass percentage of Al is 11.5%-13.5%, for example, it can be 11.5%, 11.7%, 11.9%, 12.1%, 12.3%, 12.5%, 12.7%, 12.9%, 13.1%, 13.3% or 13.5%, the mass percentage of Y is 0.2%-0.7%, for example, it can be 0.2%, 0.3%, 0.4%, 0.5%, 0.6% or 0.7%, and the mass percentages of the above components include but are not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0020] Preferably, the NiCoCrAlY metal ceramic composite powder includes, by mass percentage, Ni: 31%-32.5%, Cr: 20%-21.5%, Al: 8%-9%, Y: 0.5%-2%, CeO2: 0.5%-1.5%, Al2O3: 0.5%-1.5%, and the balance is Co.

[0021] In the NiCoCrAlY metal ceramic composite powder, the mass percentage of Ni is 31%-32.5%, for example, it can be 31%, 31.2%, 31.4%, 31.6%, 31.8%, 32%, 32.2%, 32.4% or 32.5%, the mass percentage of Cr is 20%-21.5%, for example, it can be 20%, 20.2%, 20.4%, 20.6%, 20.8%, 21%, 21.2%, 21.4% or 21.5%, the mass percentage of Al is 8%-9%, for example, it can be 8%, 8.2%, 8.4%, 8.6%, 8.8% or 9%, and the mass percentage of Y is 0. The mass percentage of CeO2 is 0.5wt%-1.5%, for example, it can be 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.2%, 1.4%, 1.6%, 1.8% or 2%, the mass percentage of CeO2 is 0.5wt%-1.5%, for example, it can be 0.5%, 0.7%, 0.9%, 1.1%, 1.3% or 1.5%, the mass percentage of Al2O3 is 0.5wt%-1.5%, for example, it can be 0.5%, 0.7%, 0.9%, 1.1%, 1.3% or 1.5%, the mass percentage of the above-mentioned components includes but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0022] In the first CeYSZ ceramic layer, ZrO2 can improve the thermal insulation performance of the first CeYSZ ceramic layer. If ZrO2 is insufficient, the thermal conductivity of the coating will increase, and the thermal insulation performance will not be effectively improved. If ZrO2 is excessive, the high-temperature phase stability of the coating will deteriorate. CeO2 can improve the thermal insulation performance, thermal expansion coefficient and thermal shock resistance of the first CeYSZ ceramic layer. If CeO2 is insufficient, the coating is prone to thermal expansion coefficient mismatch. If CeO2 is excessive, the mechanical properties of the coating will decrease and the cost will be too high. Y2O3 can improve the high-temperature phase stability of the first CeYSZ ceramic layer. If Y2O3 is insufficient, the improvement of high-temperature phase stability is not ideal. If Y2O3 is excessive, the thermal insulation performance will be reduced and the cost will be too high.

[0023] Preferably, the CeYSZ first ceramic layer comprises, by mass percentage, ZrO2: 72%-75%, CeO2: 23%-25% and Y2O3: 2%-3%.

[0024] In the first ceramic layer of CeYSZ, the mass percentage of ZrO2 is 72%-75%, the mass percentage of CeO2 is 23%-25%, for example, it can be 23%, 23.2%, 23.4%, 23.6%, 23.8%, 24%, 24.2%, 24.4%, 24.6%, 24.8% or 25%, the mass percentage of Y2O3 is 2%-3%, for example, it can be 2%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9% or 3%, and the mass percentages of the above-mentioned components include but are not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0025] In the second GdYbYSZ ceramic layer, ZrO2 can improve the thermal insulation performance of the second GdYbYSZ ceramic layer. If ZrO2 is insufficient, the thermal insulation performance of the coating is not ideal and will lead to thermal expansion coefficient mismatch. If ZrO2 is excessive, the high-temperature phase stability of the coating will deteriorate. Y2O3 can improve the high-temperature phase stability of the second GdYbYSZ ceramic layer. If Y2O3 is excessive, the thermal insulation performance of the second GdYbYSZ ceramic layer and the cohesive strength of the coating will deteriorate. If Y2O3 is insufficient, the high-temperature phase stability of the coating will not be improved ideally. Yb2 O3 can improve the thermal insulation performance of the second ceramic layer of GdYbYSZ. If Yb2O3 is insufficient, the lattice distortion of the coating will decrease, which will lead to a decrease in the thermal insulation performance of the coating. If Yb2O3 is excessive, it may cause a mismatch in the thermal expansion coefficient of the coating and an increase in cost. Gd2O3 can improve the thermal insulation and corrosion resistance of the second ceramic layer of GdYbYSZ. If Gd2O3 is insufficient, the high-temperature stability and CMAS (calcium magnesium aluminum silicate) corrosion resistance of the coating will deteriorate. If Gd2O3 is excessive, the coating cost will increase and even cause a mismatch in the thermal expansion coefficient of the coating.

[0026] Preferably, the GdYbYSZ second ceramic layer comprises, by mass percentage, ZrO2: 78%-82%, Y2O3: 8%-10%, Yb2O3: 5%-6% and Gd2O3: 5%-6%.

[0027] In the second GdYbYSZ ceramic layer, the mass percentage of ZrO2 is 78%-82%, for example, it can be 78%, 78.5%, 79%, 79.5%, 80%, 80.5%, 81%, 81.5% or 82%, the mass percentage of Y2O3 is 8%-10%, for example, it can be 8%, 8.2%, 8.4%, 8.6%, 8.8%, 9%, 9.2%, 9.4%, 9.6%, 9.8% or 10%, and the mass percentage of Yb2O3 is 5%-6%. , for example, it can be 5%, 5.1%, 5.2%, 5.3%, 5.4%, 5.5%, 5.6%, 5.7%, 5.8%, 5.9% or 6%, the mass percentage of Gd2O3 is 5%-6%, for example, it can be 5%, 5.1%, 5.2%, 5.3%, 5.4%, 5.5%, 5.6%, 5.7%, 5.8%, 5.9% or 6%, the mass percentage of the above components includes but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0028] In the present invention, in the thermal protection layer, the thickness between each layer affects the thermal insulation performance, bonding strength and thermal shock resistance of the coating. If the NiCoCrAlY first adhesive layer is too thick, the growth rate of TGO in the coating will be too fast under high temperature and high pressure conditions, thereby causing stress mismatch. The Al element in the first adhesive layer will diffuse into the TGO between the second adhesive layer and the ceramic layer at high temperature. If the NiCoCrAlY first adhesive layer is too thin, it cannot effectively insulate and cannot provide sufficient Al elements for the second adhesive layer, resulting in the generation of spinel structure TGO in the second adhesive layer, causing crack expansion; if the NiCoCrAlY second adhesive layer is too thick, the bonding strength of the coating will decrease. If it is too thin, the thermal shock resistance of the coating will decrease, and the coating will easily peel off; if the CeYSZ first ceramic layer is too thick, the bonding strength of the coating will also decrease. If it is too thin, a good thermal shock resistance effect cannot be achieved; if the GdYbYSZ second ceramic layer is too thick, the bonding strength of the coating will decrease. If it is too thin, the thermal insulation performance and corrosion resistance of the coating will decrease.

[0029] Preferably, the thickness of the NiCoCrAlY first binder layer is 10 μm-30 μm, for example, it can be 10 μm, 12 μm, 14 μm, 16 μm, 18 μm, 20 μm, 22 μm, 24 μm, 26 μm, 28 μm or 30 μm, including but not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0030] Preferably, the thickness of the NiCoCrAlY second bonding layer is 10 μm-30 μm, for example, it can be 10 μm, 12 μm, 14 μm, 16 μm, 18 μm, 20 μm, 22 μm, 24 μm, 26 μm, 28 μm or 30 μm, including but not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0031] Preferably, the thickness of the CeYSZ first ceramic layer is 30 μm-60 μm, for example, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm or 60 μm, including but not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0032] Preferably, the thickness of the GdYbYSZ second ceramic layer is 30 μm-60 μm, for example, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm or 60 μm, including but not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0033] Preferably, the porosity of the NiCoCrAlY first binder layer is 0.5%-5%, for example, it can be 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5% or 5%, including but not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0034] Preferably, the porosity of the NiCoCrAlY second bonding layer is 0.5%-5%, for example, it can be 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5% or 5%, including but not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0035] Preferably, the porosity of the CeYSZ first ceramic layer is 2%-7%, for example, it can be 2%, 3%, 4%, 5%, 6% or 7%, including but not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0036] Preferably, the porosity of the GdYbYSZ second ceramic layer is 2%-7%, for example, 2%, 3%, 4%, 5%, 6% or 7%, including but not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0037] In a second aspect, the present invention provides a method for preparing the thermal protective coating according to the first aspect, the preparation method comprising:

[0038] Spraying the first bonding layer material, the second bonding layer material, the first ceramic layer material and the second ceramic layer material on the surface of the substrate in sequence to form a NiCoCrAlY first bonding layer, a NiCoCrAlY second bonding layer, a CeYSZ first ceramic layer and a GdYbYSZ second ceramic layer in sequence;

[0039] The second bonding layer material includes NiCoCrAlY metal ceramic composite powder;

[0040] The NiCoCrAlY metal ceramic composite powder includes CeO2 and Al2O3.

[0041] The method for preparing the thermal protective coating provided by the present invention further comprises pre-treating the surface of the substrate before spraying, wherein the pre-treatment comprises sandblasting and ultrasonic cleaning.

[0042] Preferably, the sandblasting includes selecting dry, high hardness, multi-angular sand with a particle size of 16-22 meshes. For example, the particle size of the sand can be 16 mesh, 17 mesh, 18 mesh, 19 mesh, 20 mesh, 21 mesh or 22 mesh, including but not limited to the listed values. The sand can be any one of brown corundum sand, copper ore sand or steel sand, or a combination of at least two of them.

[0043] Use clean compressed air filtered through oil and water for sandblasting, the sandblasting pressure is not less than 0.7MPa, for example, it can be 0.7MPa, 0.8MPa, 0.9MPa, 1MPa or 1.2MPa, the sandblasting angle is usually 65°-75°, for example, it can be 65°, 67°, 69°, 71°, 73° or 75°, the above sandblasting process parameters include but are not limited to the listed values, and other values ​​not listed in the numerical range are also applicable. In order to avoid work hardening, the sandblasting time should not be too long. After sandblasting pretreatment, the oil and rust layer on the surface of the substrate should be completely removed to expose the fresh surface. The roughness of the metal surface after sandblasting should reach Sa2.5 level or above.

[0044] The ultrasonic cleaning comprises placing the sandblasted substrate into anhydrous ethanol, ultrasonically cleaning for 2-5 minutes, and then taking it out. For example, the ultrasonic cleaning time can be 2 minutes, 3 minutes, 4 minutes or 5 minutes, and then naturally air-drying.

[0045] Preferably, in terms of mass percentage, the first bonding layer material includes Co: 20%-26%, Cr: 15%-19%, Al: 11.5%-13.5%, Y: 0.2%-0.7%, and the balance is Ni.

[0046] In the first bonding layer material, the mass percentage of Co is 20%-26%, for example, it can be 20%, 21%, 22%, 23%, 24%, 25% or 26%, the mass percentage of Cr is 15%-19%, for example, it can be 15%, 16%, 17%, 18% or 19%, the mass percentage of Al is 11.5%-13.5%, for example, it can be 11.5%, 11.7%, 11.9%, 12.1%, 12.3%, 12.5%, 12.7%, 12.9%, 13.1%, 13.3% or 13.5%, the mass percentage of Y is 0.2%-0.7%, for example, it can be 0.2%, 0.3%, 0.4%, 0.5%, 0.6% or 0.7%, and the mass percentages of the above components include but are not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0047] Preferably, the second bonding layer material comprises NiCoCrAlY metal ceramic composite powder.

[0048] Preferably, the method for preparing the NiCoCrAlY metal ceramic composite powder comprises:

[0049] The raw material of NiCoCrAlY metal ceramic composite powder is wet ball-milled to obtain NiCoCrAlY composite slurry, which is spray-dried to obtain NiCoCrAlY composite powder, and the NiCoCrAlY composite powder is sintered to obtain NiCoCrAlY metal ceramic composite powder.

[0050] In the present invention, wet ball milling and spray drying are both existing technologies, and the corresponding process parameters are not particularly limited.

[0051] The present invention adopts a combination of ball milling, spray granulation and sintering to prepare NiCoCrAlY metal ceramic composite powder. On the one hand, the prepared NiCoCrAlY metal ceramic composite powder has low oxygen content, high sphericity and uniform composition. On the other hand, it can improve the ability of the NiCoCrAlY second bonding layer to resist the stress mismatch between the NiCoCrAlY first bonding layer with a higher thermal expansion coefficient and the CeYSZ first ceramic layer with a lower thermal expansion coefficient.

[0052] Preferably, the method for preparing the NiCoCrAlY metal ceramic composite powder further comprises screening the sintered NiCoCrAlY metal ceramic composite powder using a sieve with a mesh size of 300 or larger, for example, 300 mesh, 400 mesh, 500 mesh, 600 mesh, 700 mesh, 800 mesh, 900 mesh or 1000 mesh can be used.

[0053] Preferably, in terms of mass percentage, the raw materials of the NiCoCrAlY metal ceramic composite powder include Ni: 31%-32.5%, Cr: 20%-21.5%, Al: 8%-9%, Y: 0.5%-2%, CeO2: 0.5%-1.5%, Al2O3: 0.5%-1.5%, and the balance is Co.

[0054] In the NiCoCrAlY metal ceramic composite powder, the mass percentage of Ni is 31%-32.5%, for example, it can be 31%, 31.2%, 31.4%, 31.6%, 31.8%, 32%, 32.2%, 32.4% or 32.5%, the mass percentage of Cr is 20%-21.5%, for example, it can be 20%, 20.2%, 20.4%, 20.6%, 20.8%, 21%, 21.2%, 21.4% or 21.5%, the mass percentage of Al is 8%-9%, for example, it can be 8%, 8.2%, 8.4%, 8.6%, 8.8% or 9%, and the mass percentage of Y is 0 .5%-2%, for example, it can be 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.2%, 1.4%, 1.6%, 1.8% or 2%, the mass percentage of CeO2 is 0.5wt%-1.5%, for example, it can be 0.5%, 0.7%, 0.9%, 1.1%, 1.3% or 1.5%, the mass percentage of Al2O3 is 0.5wt%-1.5%, for example, it can be 0.5%, 0.7%, 0.9%, 1.1%, 1.3% or 1.5%, the mass percentage of the above-mentioned components includes but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0055] Preferably, in terms of mass percentage, the first ceramic layer material includes ZrO2: 72%-75%, CeO2: 23%-25% and Y2O3: 2%-3%.

[0056] In the first ceramic layer material, the mass percentage of ZrO2 is 72%-75%, for example, it can be 72%, 72.5%, 73%, 73.5%, 74%, 74.5% or 75%, the mass percentage of CeO2 is 23%-25%, for example, it can be 23%, 23.2%, 23.4%, 23.6%, 23.8%, 24%, 24.2%, 24.4%, 24.6%, 24.8% or 25%, the mass percentage of Y2O3 is 2%-3%, for example, it can be 2%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9% or 3%, the mass percentages of the above components include but are not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0057] Preferably, in terms of mass percentage, the second ceramic layer material comprises: ZrO2: 78%-82%, Y2O3: 8%-10%, Yb2O3: 5%-6% and Gd2O3: 5%-6%.

[0058] In the second ceramic layer material, the mass percentage of ZrO2 is 78%-82%, for example, it can be 78%, 78.5%, 79%, 79.5%, 80%, 80.5%, 81%, 81.5% or 82%, the mass percentage of Y2O3 is 8%-10%, for example, it can be 8%, 8.2%, 8.4%, 8.6%, 8.8%, 9%, 9.2%, 9.4%, 9.6%, 9.8% or 10%, and the mass percentage of Yb2O3 is 5%-6%, for example It can be 5%, 5.1%, 5.2%, 5.3%, 5.4%, 5.5%, 5.6%, 5.7%, 5.8%, 5.9% or 6%. The mass percentage of Gd2O3 is 5%-6%, for example, it can be 5%, 5.1%, 5.2%, 5.3%, 5.4%, 5.5%, 5.6%, 5.7%, 5.8%, 5.9% or 6%. The mass percentages of the above components include but are not limited to the listed values, and other unlisted values ​​within the numerical range are equally applicable.

[0059] Preferably, the spraying method includes supersonic plasma spraying.

[0060] According to the special structural characteristics of the engine, the inner wall of the combustion chamber is a narrow inner hole space with a small size. Conventional plasma spraying and vapor deposition cannot prepare a uniform coating. Supersonic plasma spraying is used to prepare the thermal protection layer, and the process parameters of supersonic plasma spraying are optimized to ensure that the prepared thermal protection coating has a uniform size.

[0061] Preferably, the angle between the spray gun and the substrate surface is 60°-70°, for example, it can be 60°, 61°, 62°, 63°, 64°, 65°, 66°, 67°, 68°, 69° or 70°, including but not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0062] Preferably, during the spraying process, the movement speed of the spray gun is 12 mm / s-20 mm / s, for example, it can be 12 mm / s, 14 mm / s, 16 mm / s, 18 mm / s, 19 mm / s or 20 mm / s, including but not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0063] Preferably, before spraying, the substrate is also preheated.

[0064] In the present invention, a single pass of the spray gun over the entire substrate is considered as one pass. Before spraying, the substrate is preheated using a plasma flame flow along the spraying path for 2 to 5 times, for example, 2, 3, 4 or 5 times, with an interval of 1s to 3s each time, for example, 1s, 2s or 3s. After the preheating is completed, the first bonding layer material is sprayed.

[0065] The preparation method provided by the present invention also includes, before spraying, setting a cleaning gas that moves with the gun at the mouth of the spray gun, and adding a dust collector with strong suction power under the substrate to prevent dust from contaminating the coating.

[0066] Preferably, the purge gas pressure is 0.2 MPa-0.5 MPa, for example, 0.2 MPa, 0.3 MPa, 0.4 MPa or 0.5 MPa, including but not limited to the listed values.

[0067] Preferably, during the spraying process, cooling gas is provided behind the substrate, and the cooling gas pressure is 0.4 MPa-0.8 MPa, for example, it can be 0.4 MPa, 0.5 MPa, 0.6 MPa, 0.7 MPa, or 0.8 MPa, including but not limited to the listed values.

[0068] Preferably, the number of times the first bonding layer material and the second bonding layer material are sprayed is independently 2 to 5 times, for example, 2, 3, 4 or 5 times, and the interval between each spraying is 5s to 15s, for example, 5s, 6s, 7s, 8, 9s, 10s, 11s, 12s, 13s, 14s or 15s, including but not limited to the listed values, to ensure that the substrate and the coating are sufficiently cooled to prevent excessive thermal stress from causing the coating to fall off.

[0069] Preferably, the interval time between spraying the first bonding layer material and spraying the second bonding layer material is less than or equal to 10 minutes, for example, it can be 10 minutes, 9 minutes, 8 minutes, 7 minutes, 6 minutes or 5 minutes, including but not limited to the listed values. If the interval time is too long, the substrate will cool down and the quenching stress of the NiCoCrAlY second bonding layer will increase.

[0070] Preferably, the power of spraying the first bonding layer material and the power of spraying the second bonding layer material are independently 48kW-52kW, for example, 48kW, 49kW, 50kW, 51kW or 52kW, including but not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0071] Preferably, the powder feeding rates for spraying the first bonding layer material and spraying the second bonding layer material are independently 5g / min-10g / min, for example, 5g / min, 6g / min, 7g / min, 8g / min, 9g / min or 10g / min, including but not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0072] Preferably, the main gas for spraying the first bonding layer material and the second bonding layer material is Ar, and the secondary gas is H2.

[0073] Preferably, the main air flow rate for spraying the first bonding layer material and the second bonding layer material is independently 80L / min-120L / min, for example, it can be 80L / min, 90L / min, 100L / min, 110L / min or 120L / min, including but not limited to the listed values, and the secondary air flow rate is 10L / min-20L / min, for example, it can be 10L / min, 12L / min, 14L / min, 16L / min, 18L / min or 20L / min, including but not limited to the listed values.

[0074] Preferably, the powder feeding gas pressures for spraying the first bonding layer material and the second bonding layer material are independently 0.3MPa-0.7MPa, for example, 0.3MPa, 0.4MPa, 0.5MPa, 0.6MPa or 0.7MPa, including but not limited to the values ​​listed above.

[0075] Preferably, the power of spraying the first ceramic layer material and the power of spraying the second ceramic layer material are each independently 60kW-65kW, for example, it can be 60kW, 61kW, 62kW, 63kW, 64kW or 65kW, including but not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0076] Preferably, the powder feeding rates for spraying the first ceramic layer material and spraying the second ceramic layer material are independently 3g / min-8g / min, for example, 3g / min, 4g / min, 5g / min, 6g / min, 7g / min or 8g / min, including but not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0077] Preferably, the main gas for spraying the first ceramic layer material and the second ceramic layer material is Ar, and the secondary gas is H2.

[0078] Preferably, the main air flow rate for spraying the first ceramic layer material and the second ceramic layer material is independently 60L / min-70L / min, for example, it can be 60L / min, 62L / min, 64L / min, 66L / min, 68L / min or 120L / min, including but not limited to the listed values, and the secondary air flow rate is 15L / min-25L / min, for example, it can be 15L / min, 17L / min, 19L / min, 21L / min, 23L / min or 25L / min, including but not limited to the listed values.

[0079] Preferably, the powder feeding air flow rate for spraying the first ceramic layer material and the second ceramic layer material is independently 3L / min-7L / min, for example, it can be 3L / min, 4L / min, 5L / min, 6L / min or 7L / min, including but not limited to the listed values, and the powder feeding pressure is 0.4MPa-0.8MPa, for example, it can be 0.4MPa, 0.5MPa, 0.6MPa, 0.7MPa or 0.8MPa, including but not limited to the listed values.

[0080] Preferably, the powder delivery gas flow rates for spraying the first ceramic layer material and spraying the second ceramic layer material are each independently 8L / min-12L / min, for example, 7L / min, 9L / min, 10L / min, 11L / min or 12L / min, including but not limited to the listed values, and the powder delivery pressure is 0.5MPa-0.9MPa, for example, 0.5MPa, 0.6MPa, 0.7MPa, 0.8MPa or 0.9MPa, including but not limited to the listed values.

[0081] Preferably, the number of times the first ceramic layer material and the second ceramic layer material are sprayed is independently 8-12 times, for example, 8 times, 9 times, 10 times, 11 times or 12 times, and the interval between each spraying is 3s-8s, for example, 3s, 4s, 5s, 6, 7s or 8s, including but not limited to the listed values, and spraying is continued after a pause of 30s every 4-6 times.

[0082] In a third aspect, the present invention provides an application of the thermal protection coating as described in the first aspect, wherein the thermal protection coating is applied in the field of engines.

[0083] Compared with the prior art, the present invention has the following beneficial effects:

[0084] (1) The present invention improves the use temperature and thermal strain tolerance of the coating by constructing a coating structure of a double-layer adhesive layer and a double-layer ceramic layer, effectively preventing the problem of coating peeling, so that each layer of coating can give full play to the material's superior performance and avoid inferior performance.

[0085] (2) The present invention introduces CeO2 and Al2O3 nanoparticle reinforcement phases into the second bonding layer of NiCoCrAlY, which can hinder the formation of spinel oxides, effectively inhibit the generation of cracks, and prevent the expansion of cracks. In addition, the addition of CeO2 can inhibit the oxidation of the coating and improve the oxidation resistance of the coating.

[0086] (3) The present invention uses the GdYbYSZ second ceramic layer as the ceramic surface layer, which significantly improves the stability and corrosion resistance of the coating at high temperatures. BRIEF DESCRIPTION OF THE DRAWINGS

[0087] Figure 1 This is a process flow chart of the preparation of the thermal protective coating provided in Example 1.

[0088] Figure 2 This is the SEM image of the NiCoCrAlY metal ceramic composite powder prepared in Example 1.

[0089] Figure 3 This is a SEM image of a cross section of the thermal protection coating provided in Example 1.

[0090] Figure 4 This is the tensile load-displacement curve of the thermal protective coating provided in Example 1. DETAILED DESCRIPTION

[0091] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0092] Example 1

[0093] The present embodiment provides a thermal protective coating, comprising a NiCoCrAlY first bonding layer with a thickness of 20 μm and a porosity of 3.5%, a NiCoCrAlY second bonding layer with a thickness of 25 μm and a porosity of 4%, a CeYSZ first ceramic layer with a thickness of 40 μm and a porosity of 5%, and a GdYbYSZ second ceramic layer with a thickness of 45 μm and a porosity of 4.5%, which are sequentially arranged on the surface of a substrate.

[0094] In terms of mass percentage, the NiCoCrAlY first bonding layer includes Co: 23%, Cr: 17%, Al: 12.5%, Y: 0.5% and Ni: 47%, the NiCoCrAlY second bonding layer is sprayed with NiCoCrAlY metal ceramic composite powder consisting of Ni: 31%, Cr: 20%, Al: 8%, Y: 1%, CeO2: 1%, Al2O3: 0.5% and Co: 38.5%, the CeYSZ first ceramic layer includes ZrO2: 72.5%, CeO2: 25% and Y2O3: 2.5%; the GdYbYSZ second ceramic layer includes ZrO2: 79.8%, Y2O3: 9%, Yb2O3: 5.7% and Gd2O3: 5.5%.

[0095] The preparation process of the thermal protective coating is shown in Figure 1 , the preparation method comprises:

[0096] (1) Preparation of NiCoCrAlY metal ceramic composite powder. Metal powders were weighed according to the mass ratio of Ni: 31%, Cr: 20%, Al: 8%, Y: 1%, CeO2: 1%, Al2O3: 0.5% and Co: 38.5%, and water was used as the medium, polyvinyl alcohol was used as the binder, polyethylene glycol was used as the dispersant, and Φ7 yttrium oxide ceramic balls were used. The ball-to-material ratio was 1:5 and the rotation speed was 500 rpm for 3 hours to prepare a NiCoCrAlY composite slurry with a solid content of 50%, wherein the mass percentage of polyvinyl alcohol was 10% and the mass percentage of polyethylene glycol was 1%. The NiCoCrAlY composite slurry was spray granulated to obtain NiCoCrAlY composite powder, with a feeding rate of 75 mL / min, an air inlet temperature of 250°C, and an air outlet temperature of 120°C; the NiCoCrAlY composite powder was sintered under argon protection at a sintering temperature of 1050°C and a sintering time of 3 hours to obtain NiCoCrAlY metal ceramic composite powder, which was sieved using a 600-mesh screen. The SEM image of the NiCoCrAlY metal ceramic composite powder prepared in this embodiment is shown in FIG. Figure 2 .

[0097] (2) Pre-treat the surface of the substrate. Use brown corundum sand with a particle size of 18 mesh and clean compressed air filtered through oil and water for sandblasting. The sandblasting pressure is 0.8 MPa and the sandblasting angle is 70°. Sandblasting is stopped when the roughness of the metal surface reaches Sa2.5. Put the sandblasted substrate into anhydrous ethanol, ultrasonically clean it for 3 minutes, then take it out and air dry it naturally.

[0098] (3) Spraying thermal protective coating. Before spraying, set the purge gas pressure at 0.3 MPa at the spray gun port, and add a dust collector with strong suction under the substrate. Set the angle between the spray gun and the substrate surface to 65°, the spray gun movement speed to 15 mm / s, and use the plasma flame flow to preheat the substrate three times, with an interval of 2 seconds each time.

[0099] The main gas is Ar with a flow rate of 90L / min, and the secondary gas is H2 with a flow rate of 15L / min. The spraying power is set to 50kW and the powder feeding rate is 7.5g / min. The powder feeding gas pressure is 0.5MPa, and the first bonding layer material composed of Co: 23%, Cr: 17%, Al: 12.5%, Y: 0.5% and Ni: 47% is sprayed on the surface of the substrate three times in sequence, with an interval of 10s between each spraying, to obtain a NiCoCrAlY first bonding layer. During the spraying process, a cooling gas of 0.6MPa is set behind the substrate. After the spraying of the NiCoCrAlY first bonding layer is completed, the NiCoCrAlY metal ceramic composite powder prepared in step (1) is sprayed on the surface of the first bonding layer three times with an interval of 6min using the same spraying process, with an interval of 10s each time, to obtain a NiCoCrAlY second bonding layer.

[0100] With Ar as the main gas with a flow rate of 65L / min and H2 as the secondary gas with a flow rate of 20L / min, the spraying power is set to 63kW, and the powder feeding rate is 6g / min; the upper powder feeding gas flow rate is 5L / min, the upper powder feeding pressure is 0.6MPa, the lower powder feeding gas flow rate is 10L / min, and the lower powder feeding pressure is 0.8MPa. The first ceramic layer material is sprayed on the surface of the second bonding layer of NiCoCrAlY 5 times in sequence, with an interval of 5s between each spraying, and after a pause of 30s, it is sprayed again for 5 times with a composition of ZrO2:72.5%, CeO2 :25% and Y2O3:2.5%, with an interval of 5s between each spraying and a total of 10 sprayings to obtain a CeYSZ first ceramic layer. During the spraying process, a cooling gas of 0.6MPa was set behind the substrate. After the spraying of the CeYSZ first ceramic layer was completed, a second ceramic layer material composed of ZrO2:79.8%, Y2O3:9%, Yb2O3:5.7% and Gd2O3:5.5% was sprayed on the surface of the CeYSZ first ceramic layer 10 times using the same spraying process to obtain a GdYbYSZ second ceramic layer.

[0101] The SEM image of the cross section of the thermal protection coating prepared in this embodiment is shown in Figure 3 .

[0102] Example 2

[0103] The present embodiment provides a thermal protective coating, comprising a NiCoCrAlY first bonding layer with a thickness of 10 μm and a porosity of 0.5%, a NiCoCrAlY second bonding layer with a thickness of 10 μm and a porosity of 1%, a CeYSZ first ceramic layer with a thickness of 30 μm and a porosity of 2%, and a GdYbYSZ second ceramic layer with a thickness of 30 μm and a porosity of 2.5%, which are sequentially arranged on the surface of a substrate.

[0104] In terms of mass percentage, the NiCoCrAlY first bonding layer includes Co: 20%, Cr: 15%, Al: 11.5%, Y: 0.2% and Ni: 53.3%, the NiCoCrAlY second bonding layer is sprayed with NiCoCrAlY metal ceramic composite powder consisting of Ni: 32%, Cr: 21%, Al: 8.5%, Y: 0.5%, CeO2: 1.5%, Al2O3: 1.5% and Co: 35%, the CeYSZ first ceramic layer includes ZrO2: 73%, CeO2: 24% and Y2O3: 3%; the GdYbYSZ second ceramic layer includes ZrO2: 82%, Y2O3: 8%, Yb2O3: 5% and Gd2O3: 5%.

[0105] The preparation method of the thermal protective coating comprises:

[0106] (1) Preparation of NiCoCrAlY metal ceramic composite powder. The process is the same as step (1) of Example 1 except that metal powders are weighed according to the mass ratio of Ni: 32%, Cr: 21%, Al: 8.5%, Y: 0.5%, CeO2: 1.5%, Al2O3: 1.5% and Co: 35%.

[0107] (2) Pre-treating the surface of the substrate, wherein the pre-treatment method is the same as that in Example 1.

[0108] (3) Spraying thermal protective coating. Before spraying, set the purge gas pressure at 0.2MPa at the spray gun port, and add a dust collector with strong suction under the substrate. Set the angle between the spray gun and the substrate surface to 60°, the spray gun movement speed to 12mm / s, and use the plasma flame flow to preheat the substrate 4 times, with an interval of 3s each time.

[0109] The main gas is Ar with a flow rate of 80L / min, the secondary gas is H2 with a flow rate of 10L / min, the spraying power is set to 48kW, and the powder feeding rate is 5g / min; the powder feeding gas pressure is 0.3MPa, and the first bonding layer material with a composition of Co: 20%, Cr: 15%, Al: 11.5%, Y: 0.2% and Ni: 53.3% is sprayed on the surface of the substrate twice in sequence, with an interval of 5s between each spraying, to obtain a NiCoCrAlY first bonding layer. During the spraying process, a cooling gas of 0.4MPa is set behind the substrate; after the spraying of the NiCoCrAlY first bonding layer is completed, the NiCoCrAlY metal ceramic composite powder prepared in step (1) is sprayed on the surface of the first bonding layer twice with an interval of 10min using the same spraying process, with an interval of 5s each time, to obtain a NiCoCrAlY second bonding layer.

[0110] With Ar as the main gas with a flow rate of 60L / min and H2 as the secondary gas with a flow rate of 15L / min, the spraying power is set to 60kW, and the powder feeding rate is 3g / min; the upper powder feeding gas flow rate is 3L / min, the upper powder feeding pressure is 0.4MPa, the lower powder feeding gas flow rate is 8L / min, and the lower powder feeding pressure is 0.5MPa. The first ceramic layer material is sprayed on the surface of the second bonding layer of NiCoCrAlY 4 times in sequence, with an interval of 3s between each spraying, and after a pause of 30s, the first ceramic layer material is sprayed 4 times with a composition of ZrO2:73%, C The first ceramic layer material of CeYSZ is composed of ZrO2: 24% and Y2O3: 3%, and each spraying interval is 3s, and it is sprayed 8 times in total to obtain the first ceramic layer of CeYSZ. During the spraying process, a cooling gas of 0.4MPa is set behind the substrate. After the spraying of the first ceramic layer of CeYSZ is completed, the second ceramic layer material composed of ZrO2: 82%, Y2O3: 8%, Yb2O3: 5% and Gd2O3: 5% is sprayed on the surface of the first ceramic layer of CeYSZ 8 times with the same spraying process to obtain the second ceramic layer of GdYbYSZ.

[0111] Example 3

[0112] The present embodiment provides a thermal protective coating, comprising a NiCoCrAlY first bonding layer with a thickness of 30 μm and a porosity of 5%, a NiCoCrAlY second bonding layer with a thickness of 30 μm and a porosity of 4.5%, a CeYSZ first ceramic layer with a thickness of 60 μm and a porosity of 7%, and a GdYbYSZ second ceramic layer with a thickness of 60 μm and a porosity of 7%, which are sequentially arranged on the surface of a substrate.

[0113] In terms of mass percentage, the NiCoCrAlY first bonding layer includes Co: 26%, Cr: 19%, Al: 13.5%, Y: 0.7% and Ni: 40.8%, the NiCoCrAlY second bonding layer is sprayed with NiCoCrAlY metal ceramic composite powder consisting of Ni: 32.5%, Cr: 21.5%, Al: 9%, Y: 2%, CeO2: 0.5%, Al2O3: 1% and Co: 33.5%, the CeYSZ first ceramic layer includes ZrO2: 72%, CeO2: 25% and Y2O3: 3%; the GdYbYSZ second ceramic layer includes ZrO2: 78%, Y2O3: 10%, Yb2O3: 6% and Gd2O3: 6%.

[0114] The preparation method of the thermal protective coating comprises:

[0115] (1) Preparation of NiCoCrAlY metal ceramic composite powder. The process is the same as step (1) of Example 1 except that metal powders are weighed according to the mass ratio of Ni: 32.5%, Cr: 21.5%, Al: 9%, Y: 2%, CeO2: 0.5%, Al2O3: 1% and Co: 33.5%.

[0116] (2) Pre-treating the surface of the substrate, wherein the pre-treatment method is the same as that in Example 1.

[0117] (3) Spraying thermal protective coating. Before spraying, set the purge gas pressure at 0.5 MPa at the spray gun port, and add a dust collector with strong suction under the substrate. Set the angle between the spray gun and the substrate surface to 68°, the spray gun movement speed to 20 mm / s, and use the plasma flame flow to preheat the substrate 5 times, with an interval of 1 second each time.

[0118] The main gas is Ar with a flow rate of 120L / min, and the secondary gas is H2 with a flow rate of 20L / min. The spraying power is set to 52kW and the powder feeding rate is set to 10g / min. The powder feeding gas pressure is 0.7MPa, and the first bonding layer material with a composition of Co: 26%, Cr: 19%, Al: 13.5%, Y: 0.7% and Ni: 40.8% is sprayed on the surface of the substrate 5 times in sequence, with an interval of 15s between each spraying, to obtain a NiCoCrAlY first bonding layer. During the spraying process, a cooling gas of 0.8MPa is set behind the substrate. After the spraying of the NiCoCrAlY first bonding layer is completed, the NiCoCrAlY metal ceramic composite powder prepared in step (1) is sprayed on the surface of the first bonding layer 4 times with an interval of 8min using the same spraying process, with an interval of 12s each time, to obtain a NiCoCrAlY second bonding layer.

[0119] With Ar as the main gas with a flow rate of 70L / min and H2 as the secondary gas with a flow rate of 25L / min, the spraying power is set to 65kW and the powder feeding rate is 8g / min; the upper powder feeding gas flow rate is 7L / min, the upper powder feeding pressure is 0.8MPa, the lower powder feeding gas flow rate is 12L / min, and the lower powder feeding pressure is 0.9MPa. The first ceramic layer material with a composition of ZrO2:72%, CeO2:25% and Y2O3:3% is sprayed on the surface of the second bonding layer of NiCoCrAlY 6 times in sequence, with an interval of 8 seconds between each spraying. s, after pausing for 30s, continue spraying the first ceramic layer material 6 times, with an interval of 8s between each spraying, and spraying 12 times in total to obtain a CeYSZ first ceramic layer. During the spraying process, a cooling gas of 0.8MPa is set behind the substrate; after the spraying of the CeYSZ first ceramic layer is completed, the second ceramic layer material with a composition of ZrO2:78%, Y2O3:10%, Yb2O3:6% and Gd2O3:6% is sprayed on the surface of the CeYSZ first ceramic layer 12 times using the same spraying process to obtain a GdYbYSZ second ceramic layer.

[0120] Example 4

[0121] The present embodiment provides a thermal protective coating, comprising a NiCoCrAlY first bonding layer with a thickness of 22 μm and a porosity of 4.5%, a NiCoCrAlY second bonding layer with a thickness of 28 μm and a porosity of 3%, a CeYSZ first ceramic layer with a thickness of 45 μm and a porosity of 5.5%, and a GdYbYSZ second ceramic layer with a thickness of 45 μm and a porosity of 4.5%, which are sequentially arranged on the surface of a substrate.

[0122] In terms of mass percentage, the NiCoCrAlY first bonding layer includes Co: 23.5%, Cr: 17.5%, Al: 13%, Y: 0.4% and Ni: 45.6%, the NiCoCrAlY second bonding layer is sprayed with NiCoCrAlY metal ceramic composite powder consisting of Ni: 31.5%, Cr: 20.5%, Al: 8%, Y: 1%, CeO2: 1%, Al2O3: 0.5% and Co: 37.5%, the CeYSZ first ceramic layer includes ZrO2: 73.5%, CeO2: 24.3% and Y2O3: 2.2%; the GdYbYSZ second ceramic layer includes ZrO2: 79%, Y2O3: 10%, Yb2O3: 5.8% and Gd2O3: 5.2%.

[0123] The preparation method of the thermal protective coating includes the following steps: except for step (1), weighing metal powders according to the mass ratio of Ni: 31.5%, Cr: 20.5%, Al: 8%, Y: 1%, CeO2: 1%, Al2O3: 0.5% and Co: 37.5%, the first bonding layer material composition is Co: 23.5%, Cr: 17.5%, Al: 13%, Y: 0.4% and Ni: 45.6%, the first ceramic layer material composition is ZrO2: 72%, CeO2: 25% and Y2O3: 3%, the second ceramic layer material composition is ZrO2: 78%, Y2O3: 10%, Yb2O3: 6% and Gd2O3: 6%, and the rest is the same as Example 1.

[0124] Example 5

[0125] The present embodiment provides a thermal protective coating, comprising a NiCoCrAlY first bonding layer with a thickness of 27 μm and a porosity of 2.5%, a NiCoCrAlY second bonding layer with a thickness of 23 μm and a porosity of 3.3%, a CeYSZ first ceramic layer with a thickness of 50 μm and a porosity of 6.5%, and a GdYbYSZ second ceramic layer with a thickness of 55 μm and a porosity of 6.5%, which are sequentially arranged on the surface of a substrate.

[0126] In terms of mass percentage, the NiCoCrAlY first bonding layer includes Co: 24.5%, Cr: 18.5%, Al: 12%, Y: 0.3% and Ni: 44.7%, the NiCoCrAlY second bonding layer is sprayed with NiCoCrAlY metal ceramic composite powder consisting of Ni: 32%, Cr: 21%, Al: 8.3%, Y: 1.3%, CeO2: 1.1%, Al2O3: 0.7% and Co: 35.6%, the CeYSZ first ceramic layer includes ZrO2: 72.6%, CeO2: 24.6% and Y2O3: 2.8%; the GdYbYSZ second ceramic layer includes ZrO2: 80%, Y2O3: 9.1%, Yb2O3: 5.3% and Gd2O3: 5.6%.

[0127] The preparation method of the thermal protective coating includes the following steps: except for step (1) weighing metal powders according to the mass ratio of Ni: 31.5%, Cr: 20.5%, Al: 8%, Y: 1%, CeO2: 1%, Al2O3: 0.5% and Co: 37.5%, the first bonding layer material composition is Co: 24.5%, Cr: 18.5%, Al: 12%, Y: 0.3% and Ni: 44.7%, the first ceramic layer material composition is ZrO2: 72.6%, CeO2: 24.6% and Y2O3: 2.8%, the second ceramic layer material composition is ZrO2: 80%, Y2O3: 9.1%, Yb2O3: 5.3% and Gd2O3: 5.6%, and the rest are the same as Example 1.

[0128] Example 6

[0129] This embodiment provides a thermal protection coating, which is the same as Embodiment 1 except that the mass percentage of Co in the NiCoCrAlY first bonding layer is 18% and the mass percentage of Ni is adaptively adjusted to 52%.

[0130] The preparation method of the thermal protection coating is the same as that of Example 1, except that the mass percentage of Co in the first bonding layer material is adjusted to 18%, and the mass percentage of Ni is adaptively adjusted to 52%.

[0131] Example 7

[0132] This embodiment provides a thermal protection coating, which is the same as Embodiment 1 except that the mass percentage of Co in the NiCoCrAlY first bonding layer is 30% and the mass percentage of Ni is adaptively adjusted to 40%.

[0133] The preparation method of the thermal protection coating is the same as that of Example 1, except that the mass percentage of Co in the first bonding layer material is adjusted to 30%, and the mass percentage of Ni is adaptively adjusted to 40%.

[0134] Example 8

[0135] This embodiment provides a thermal protection coating, which is the same as Embodiment 1 except that the mass percentage of Cr in the NiCoCrAlY first bonding layer is 12% and the mass percentage of Ni is adaptively adjusted to 52%.

[0136] The preparation method of the thermal protection coating is the same as that of Example 1, except that the mass percentage of Cr in the first bonding layer material is adjusted to 12% and the mass percentage of Ni is adaptively adjusted to 52%.

[0137] Example 9

[0138] This embodiment provides a thermal protection coating, which is the same as Embodiment 1 except that the mass percentage of Cr in the NiCoCrAlY first bonding layer is 21% and the mass percentage of Ni is adaptively adjusted to 43%.

[0139] The preparation method of the thermal protection coating is the same as that of Example 1, except that the mass percentage of Cr in the first bonding layer material is adjusted to 21%, and the mass percentage of Ni is adaptively adjusted to 43%.

[0140] Example 10

[0141] This embodiment provides a thermal protection coating, which is the same as the embodiment except that in the NiCoCrAlY first bonding layer, the mass percentage of Al is 10%, and the mass percentage of Ni is adjusted to 49.5%.

[0142] The preparation method of the thermal protection coating is the same as that of Example 1, except that the mass percentage of Al in the first bonding layer material is 10% and the mass percentage of Ni is 49.5%.

[0143] Embodiment 11

[0144] This embodiment provides a thermal protection coating, which is the same as the embodiment except that in the NiCoCrAlY first bonding layer, the mass percentage of Al is 15%, and the mass percentage of Ni is adjusted to 44.5%.

[0145] The preparation method of the thermal protection coating is the same as that of Example 1, except that the mass percentage of Al and the mass percentage of Ni in the first bonding layer material is 15% and 44.5%, respectively.

[0146] Example 12

[0147] This embodiment provides a thermal protection coating, which is the same as Embodiment 1 except that the mass percentage of Y in the NiCoCrAlY first bonding layer is 0.1% and the mass percentage of Ni is adaptively adjusted to 47.4%.

[0148] The preparation method of the thermal protection coating is the same as that of Example 1, except that the mass percentage of Y in the first bonding layer material is adjusted to 0.1% and the mass percentage of Ni is adaptively adjusted to 47.4%.

[0149] Embodiment 13

[0150] This embodiment provides a thermal protection coating, which is the same as that of Embodiment 1 except that the mass percentage of Y in the NiCoCrAlY first bonding layer is 1% and the mass percentage of Ni is adaptively adjusted to 46.5%.

[0151] The preparation method of the thermal protection coating is the same as that of Example 1, except that the mass percentage of Cr in the first bonding layer material is adjusted to 0.1%, and the mass percentage of Ni is adaptively adjusted to 46.5%.

[0152] Embodiment 14

[0153] This embodiment provides a thermal protection coating, which is the same as Embodiment 1 except that the mass percentage of Ni in the metal-ceramic composite powder forming the NiCoCrAlY second bonding layer is 28%, and the mass percentage of Co is adaptively adjusted to 41.5%.

[0154] The preparation method of the thermal protective coating is the same as that of Example 1, except that the mass percentage of Ni in the metal powder weighed in step (1) is adjusted to 0.1%, and the mass percentage of Co is adaptively adjusted to 47.4%.

[0155] Embodiment 15

[0156] This embodiment provides a thermal protection coating, which is the same as Embodiment 1 except that the mass percentage of Ni in the metal-ceramic composite powder forming the NiCoCrAlY second bonding layer is 35%, and the mass percentage of Co is adaptively adjusted to 34.5%.

[0157] The preparation method of the thermal protective coating is the same as that of Example 1, except that the mass percentage of Ni in the metal powder weighed in step (1) is adjusted to 35%, and the mass percentage of Co is adaptively adjusted to 34.5%.

[0158] Example 16

[0159] This embodiment provides a thermal protection coating, which is the same as Embodiment 1 except that the mass percentage of Cr in the metal-ceramic composite powder forming the NiCoCrAlY second bonding layer is 15%, and the mass percentage of Co is adaptively adjusted to 43.5%.

[0160] The preparation method of the thermal protective coating is the same as that of Example 1, except that the mass percentage of Cr in the metal powder weighed in step (1) is adjusted to 15%, and the mass percentage of Co is adaptively adjusted to 23.5%.

[0161] Embodiment 17

[0162] This embodiment provides a thermal protection coating, which is the same as Embodiment 1 except that the mass percentage of Cr in the metal-ceramic composite powder forming the NiCoCrAlY second bonding layer is 25%, and the mass percentage of Co is adaptively adjusted to 33.5%.

[0163] The preparation method of the thermal protective coating is the same as that of Example 1, except that the mass percentage of Cr in the metal powder weighed in step (1) is adjusted to 25%, and the mass percentage of Co is adaptively adjusted to 33.5%.

[0164] Embodiment 18

[0165] This embodiment provides a thermal protection coating, which is the same as Embodiment 1 except that the mass percentage of Al in the metal-ceramic composite powder forming the NiCoCrAlY second bonding layer is 6%, and the mass percentage of Co is adaptively adjusted to 40.5%.

[0166] The preparation method of the thermal protective coating is the same as that of Example 1, except that the mass percentage of Al in the metal powder weighed in step (1) is adjusted to 6%, and the mass percentage of Co is adaptively adjusted to 40.5%.

[0167] Embodiment 19

[0168] This embodiment provides a thermal protection coating, which is the same as Embodiment 1 except that the mass percentage of Al in the metal-ceramic composite powder forming the NiCoCrAlY second bonding layer is 12% and the mass percentage of Co is adaptively adjusted to 34.5%.

[0169] The preparation method of the thermal protective coating is the same as that of Example 1, except that the mass percentage of Al in the metal powder weighed in step (1) is adjusted to 12%, and the mass percentage of Co is adaptively adjusted to 35.5%.

[0170] Embodiment 20

[0171] This embodiment provides a thermal protection coating, which is the same as Embodiment 1 except that the mass percentage of Y in the metal-ceramic composite powder forming the NiCoCrAlY second bonding layer is 0.2% and the mass percentage of Co is adaptively adjusted to 39.3%.

[0172] The preparation method of the thermal protective coating is the same as that of Example 1, except that the mass percentage of Y in the metal powder weighed in step (1) is adjusted to 0.2%, and the mass percentage of Co is adaptively adjusted to 39.3%.

[0173] Embodiment 21

[0174] This embodiment provides a thermal protection coating, which is the same as Embodiment 1 except that the mass percentage of Y in the metal-ceramic composite powder forming the NiCoCrAlY second bonding layer is 2.5%, and the mass percentage of Co is adaptively adjusted to 37%.

[0175] The preparation method of the thermal protective coating is the same as that of Example 1, except that the mass percentage of Y in the metal powder weighed in step (1) is adjusted to 1.5%, and the mass percentage of Co is adaptively adjusted to 37%.

[0176] Embodiment 22

[0177] This embodiment provides a thermal protection coating, which is the same as Embodiment 1 except that the mass percentage of CeO2 in the CeYSZ first ceramic layer is 20% and the mass percentage of ZrO2 is adjusted to 77.5%.

[0178] The preparation method of the thermal protection coating is the same as that of Example 1 except that the mass percentage of CeO2 in the first ceramic layer material is adjusted to 20% and the mass percentage of ZrO2 is adjusted to 77.5%.

[0179] Embodiment 23

[0180] This embodiment provides a thermal protection coating, which is the same as Embodiment 1 except that the mass percentage of CeO2 in the CeYSZ first ceramic layer is 28% and the mass percentage of ZrO2 is adjusted to 69.5%.

[0181] The preparation method of the thermal protection coating is the same as that of Example 1 except that the mass percentage of CeO2 in the first ceramic layer material is adjusted to 28% and the mass percentage of ZrO2 is adjusted to 69.5%.

[0182] Embodiment 24

[0183] This embodiment provides a thermal protection coating, which is the same as Embodiment 1 except that the mass percentage of Y2O3 in the first CeYSZ ceramic layer is 1% and the mass percentage of ZrO2 is adjusted to 74.5%.

[0184] The preparation method of the thermal protection coating is the same as that of Example 1, except that the mass percentage of Y2O3 in the first ceramic layer material is adjusted to 1% and the mass percentage of ZrO2 is adjusted to 74%.

[0185] Embodiment 25

[0186] This embodiment provides a thermal protection coating, which is the same as Embodiment 1 except that the mass percentage of Y2O3 in the CeYSZ first ceramic layer is 4% and the mass percentage of ZrO2 is adjusted to 71.5%.

[0187] The preparation method of the thermal protection coating is the same as that of Example 1, except that the mass percentage of Y2O3 in the first ceramic layer material is adjusted to 4% and the mass percentage of ZrO2 is adjusted to 71%.

[0188] Embodiment 26

[0189] This embodiment provides a thermal protection coating, which is the same as Embodiment 1 except that the mass percentage of Y2O3 in the second GdYbYSZ ceramic layer is 6% and the mass percentage of ZrO2 is adjusted to 82.8%.

[0190] The preparation method of the thermal protection coating is the same as that of Example 1, except that the mass percentage of Y2O3 in the second ceramic layer material is adjusted to 6% and the mass percentage of ZrO2 is adjusted to 82.8%.

[0191] Embodiment 27

[0192] This embodiment provides a thermal protection coating, which is the same as Embodiment 1 except that the mass percentage of Y2O3 in the second GdYbYSZ ceramic layer is 12% and the mass percentage of ZrO2 is adjusted to 76.8%.

[0193] The preparation method of the thermal protection coating is the same as that of Example 1, except that the mass percentage of Y2O3 in the second ceramic layer material is adjusted to 12% and the mass percentage of ZrO2 is adjusted to 76.8%.

[0194] Embodiment 28

[0195] This embodiment provides a thermal protection coating, which is the same as Embodiment 1 except that the mass percentage of Yb2O3 in the second GdYbYSZ ceramic layer is 4% and the mass percentage of ZrO2 is adjusted to 81.5%.

[0196] The preparation method of the thermal protection coating is the same as that of Example 1, except that the mass percentage of Yb2O3 in the second ceramic layer material is adjusted to 4% and the mass percentage of ZrO2 is adjusted to 81.5%.

[0197] Embodiment 29

[0198] This embodiment provides a thermal protection coating, which is the same as Embodiment 1 except that the mass percentage of Yb2O3 in the second GdYbYSZ ceramic layer is 7% and the mass percentage of ZrO2 is adjusted to 78.5%.

[0199] The preparation method of the thermal protection coating is the same as that of Example 1, except that the mass percentage of Yb2O3 in the second ceramic layer material is adjusted to 7% and the mass percentage of ZrO2 is adjusted to 78.5%.

[0200] Embodiment 30

[0201] This embodiment provides a thermal protection coating, which is the same as Embodiment 1 except that the mass percentage of Gd2O3 in the GdYbYSZ second ceramic layer is 4% and the mass percentage of ZrO2 is adjusted to 81.3%.

[0202] The preparation method of the thermal protection coating is the same as that of Example 1, except that the mass percentage of Gd2O3 in the second ceramic layer material is adjusted to 4% and the mass percentage of ZrO2 is adjusted to 81.3%.

[0203] Embodiment 31

[0204] This embodiment provides a thermal protection coating, which is the same as Embodiment 1 except that the mass percentage of Gd2O3 in the GdYbYSZ second ceramic layer is 7% and the mass percentage of ZrO2 is adjusted to 78.3%.

[0205] The preparation method of the thermal protection coating is the same as that of Example 1, except that the mass percentage of Gd2O3 in the second ceramic layer material is adjusted to 7% and the mass percentage of ZrO2 is adjusted to 78.3%.

[0206] Embodiment 32

[0207] This embodiment provides a thermal protection coating, which is the same as that of Embodiment 1 except that the thickness of the NiCoCrAlY first bonding layer is 5 μm.

[0208] Embodiment 33

[0209] This embodiment provides a thermal protection coating, which is the same as that of Embodiment 1 except that the thickness of the NiCoCrAlY first bonding layer is 35 μm.

[0210] Embodiment 34

[0211] This embodiment provides a thermal protection coating, which is the same as that of Embodiment 1 except that the thickness of the NiCoCrAlY second bonding layer is 5 μm.

[0212] Embodiment 35

[0213] This embodiment provides a thermal protection coating, which is the same as that of Embodiment 1 except that the thickness of the NiCoCrAlY second bonding layer is 35 μm.

[0214] Embodiment 36

[0215] This embodiment provides a thermal protection coating, which is the same as that of Embodiment 1 except that the thickness of the first CeYSZ ceramic layer is 20 μm.

[0216] Embodiment 37

[0217] This embodiment provides a thermal protection coating, which is the same as that of Embodiment 1 except that the thickness of the first CeYSZ ceramic layer is 70 μm.

[0218] Embodiment 38

[0219] This embodiment provides a thermal protection coating, which is the same as that of Embodiment 1 except that the thickness of the second GdYbYSZ ceramic layer is 20 μm.

[0220] Embodiment 39

[0221] This embodiment provides a thermal protection coating, which is the same as that of Embodiment 1 except that the thickness of the second GdYbYSZ ceramic layer is 70 μm.

[0222] Embodiment 40

[0223] This embodiment provides a thermal protection coating, which is the same as that of Embodiment 1 except that the porosity of the NiCoCrAlY first bonding layer is 0.2%.

[0224] Embodiment 41

[0225] This embodiment provides a thermal protection coating, which is the same as that of Embodiment 1 except that the porosity of the NiCoCrAlY first bonding layer is 7%.

[0226] Embodiment 42

[0227] This embodiment provides a thermal protection coating, which is the same as that of Embodiment 1 except that the porosity of the NiCoCrAlY second bonding layer is 0.2%.

[0228] Embodiment 43

[0229] This embodiment provides a thermal protection coating, which is the same as that of Embodiment 1 except that the porosity of the NiCoCrAlY second bonding layer is 7%.

[0230] Embodiment 44

[0231] This embodiment provides a thermal protection coating, which is the same as that of Embodiment 1 except that the porosity of the CeYSZ first ceramic layer is 1%.

[0232] Embodiment 45

[0233] This embodiment provides a thermal protection coating, which is the same as that of Embodiment 1 except that the porosity of the first CeYSZ ceramic layer is 9%.

[0234] Embodiment 46

[0235] This embodiment provides a thermal protection coating, which is the same as that of Embodiment 1 except that the porosity of the second GdYbYSZ ceramic layer is 1%.

[0236] Embodiment 47

[0237] This embodiment provides a thermal protection coating, which is the same as that of Embodiment 1 except that the porosity of the GdYbYSZ second ceramic layer is 9%.

[0238] Embodiment 48

[0239] This embodiment provides a thermal protective coating. The preparation method of the thermal protective coating is the same as that of Embodiment 1 except that the substrate is not preheated in step (3).

[0240] Comparative Example 1

[0241] This comparative example provides a thermal protection coating, which is the same as Example 1 except that the CeYSZ first ceramic layer is replaced by a YSZ ceramic layer.

[0242] The preparation method of the thermal protection coating is the same as that of Example 1 except that CeO2 is not added to the second ceramic coating material.

[0243] Comparative Example 2

[0244] This comparative example provides a thermal protection coating, which is the same as the embodiment except that the NiCoCrAlY second bonding layer is not provided.

[0245] The preparation method of the thermal protective coating is the same as that of Example 1 except that the NiCoCrAlY second bonding layer is not prepared.

[0246] Comparative Example 3

[0247] This comparative example provides a thermal protection coating, which is the same as the embodiment except that the NiCoCrAlY first bonding layer is not provided.

[0248] The preparation method of the thermal protective coating is the same as that of Example 1 except for preparing the NiCoCrAlY first bonding layer.

[0249] Comparative Example 4

[0250] This comparative example provides a thermal protection coating, which is the same as Example 1 except that CeO2 and Al2O3 are not added to the metal ceramic composite powder forming the NiCoCrAlY second bonding layer, and the mass percentage of Co is adaptively adjusted to 40%.

[0251] The preparation method of the thermal protective coating is the same as that of Example 1, except that CeO 2 and Al 2 O 3 are not added to the metal powder weighed in step (1), and the mass percentage of Co is adaptively adjusted to 40%.

[0252] Comparative Example 5

[0253] This comparative example provides a thermal protection coating, which is the same as Example 1 except that the mass percentage of CeO2 in the metal-ceramic composite powder forming the NiCoCrAlY second bonding layer is 0.2% and the mass percentage of Co is adaptively adjusted to 39.3%.

[0254] The preparation method of the thermal protective coating is the same as that of Example 1, except that the mass percentage of CeO2 in the metal powder weighed in step (1) is changed to 0.2% and the mass percentage of Co is adaptively adjusted to 39.3%.

[0255] Comparative Example 6

[0256] This comparative example provides a thermal protection coating, which is the same as Example 1 except that the mass percentage of CeO2 in the metal ceramic composite powder forming the NiCoCrAlY second bonding layer is 2% and the mass percentage of Co is adaptively adjusted to 37.5%.

[0257] The preparation method of the thermal protective coating is the same as that of Example 1, except that the mass percentage of CeO2 in the metal powder weighed in step (1) is changed to 1% and the mass percentage of Co is adaptively adjusted to 37.5%.

[0258] Comparative Example 7

[0259] This comparative example provides a thermal protection coating, which is the same as Example 1 except that the mass percentage of Al2O3 in the metal-ceramic composite powder forming the NiCoCrAlY second bonding layer is 0.2% and the mass percentage of Co is adaptively adjusted to 38.8%.

[0260] The preparation method of the thermal protective coating is the same as that of Example 1, except that the mass percentage of CeO2 in the metal powder weighed in step (1) is changed to 0.2% and the mass percentage of Co is adaptively adjusted to 38.8%.

[0261] Comparative Example 8

[0262] This comparative example provides a thermal protection coating, which is the same as Example 1 except that the mass percentage of Al2O3 in the metal-ceramic composite powder forming the NiCoCrAlY second bonding layer is 2% and the mass percentage of Co is adaptively adjusted to 37%.

[0263] The preparation method of the thermal protective coating is the same as that of Example 1, except that the mass percentage of CeO2 in the metal powder weighed in step (1) is changed to 2% and the mass percentage of Co is adaptively adjusted to 37%.

[0264] Performance Test:

[0265] The tensile bonding strength of the thermal protective coatings in all the above embodiments and comparative examples was determined using the national standard GB8642-2002. To avoid accidental experimental factors, 5 coating samples were measured for each test and the average value was taken. The test results are shown in Table 1. The tensile load displacement curve of the thermal protective coating in Example 1 is shown in Table 1. Figure 4 .

[0266] The thermal shock resistance of the thermal protective coatings in all the above embodiments and comparative examples was tested. The test method was as follows: the test piece sprayed with the thermal protective coating was placed in an electric furnace at 1100°C for 5 minutes, then taken out and quickly placed in 30°C water for cooling, which was recorded as one thermal shock. When the coating peeling area reached 30%, it was considered to be completely failed. The number of thermal shocks for complete failure is shown in Table 1.

[0267] The thermal conductivity of the thermal protection coatings in all the above embodiments and comparative examples was tested using a laser thermal conductivity meter at 1200° C. The test results are shown in Table 1.

[0268] Table 1

[0269]

[0270]

[0271]

[0272] According to the test data of Examples 1 to 5, the bonding strength of the thermal protection coating provided by the present invention is above 57MPa, which meets the thermal protection requirements of the engine nozzle facing high heat, strong erosion, and uneven temperature, which is borne by the inner wall of the combustion chamber of a typical rotating detonation engine, and the coating fails completely after more than 158 thermal shock cycles, which also meets similar high temperature and high pressure conditions. The thermal conductivity of the coating at 1200°C is 1.1W / (m*k), and the thermal conductivity of the coating does not fluctuate significantly as the temperature rises.

[0273] According to the test results of Example 1 and Example 6 to Example 31, when the composition of any one layer of the thermal protective coating does not meet the requirements of the present invention, the performance of the thermal protective coating will be reduced.

[0274] According to the test results of Example 1 and Example 32-Example 39, when the thickness of the thermal protection layer is too large or too small, it will affect the bonding strength of the coating and cause the performance of the thermal protection coating to decrease.

[0275] According to the test results of Example 1 and Examples 40 to 47, when the porosity of the thermal protection layer is too large or too small, it will affect the bonding strength and thermal insulation performance of the coating, thereby causing the performance of the thermal protection coating to deteriorate.

[0276] According to the test results of Example 1 and Example 48, the present invention is more conducive to preparing a coating with uniform quality and improving the performance of the thermal protective coating by preheating the substrate.

[0277] The test results of Example 1 and Comparative Example 1 prove that the present invention selects CeYSZ with a higher thermal expansion coefficient than YSZ as the first ceramic layer, so that the thermal expansion coefficient of the first ceramic layer is closer to the bonding layer material, which is more conducive to improving the performance of the thermal protection layer.

[0278] According to the data results of Example 1 and Comparative Examples 2 and 3, the present invention effectively prevents the formation of spinel oxides and cracks by using a NiCoCrAlY first bonding layer with a high Al content and a NiCoCrAlY first bonding layer with a low Al content, reduces the stress between the bonding layer and the ceramic layer, and improves the performance of the thermal protection layer.

[0279] According to the data results of Example 1 and Comparative Examples 4 to 8, if CeO2 and Al2O3 nanoparticle reinforcement phases are not added to the NiCoCrAlY second bonding layer or are not added in the mass percentage specified in the present invention, it is impossible to effectively hinder the formation of spinel oxides, inhibit the generation of cracks, prevent the expansion of cracks, and improve the oxidation resistance of the coating, thereby resulting in a decrease in the performance of the thermal protective coating.

[0280] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A thermal protective coating, characterized in that: The thermal protection coating comprises a NiCoCrAlY first bonding layer, a NiCoCrAlY second bonding layer, a CeYSZ first ceramic layer and a GdYbYSZ second ceramic layer which are sequentially arranged on the surface of the substrate; The material of the NiCoCrAlY second bonding layer includes NiCoCrAlY metal ceramic composite powder; The NiCoCrAlY metal ceramic composite powder includes CeO2 and Al2O3.

2. The thermal protection coating according to claim 1, characterized in that The NiCoCrAlY first bonding layer includes, by mass percentage, Co: 20%-26%, Cr: 15%-19%, Al: 11.5%-13.5%, Y: 0.2%-0.7%, and the balance is Ni; Preferably, the NiCoCrAlY metal ceramic composite powder includes, by mass percentage, Ni: 31%-32.5%, Cr: 20%-21.5%, Al: 8%-9%, Y: 0.5%-2%, CeO2: 0.5%-1.5%, Al2O3: 0.5%-1.5%, and the balance is Co.

3. The thermal protective coating according to claim 1 or 2, characterized in that: The CeYSZ first ceramic layer comprises, by mass percentage, 72%-75% ZrO2, 23%-25% CeO2 and 2%-3% Y2O3; Preferably, the GdYbYSZ second ceramic layer comprises, by mass percentage, ZrO2: 78%-82%, Y2O3: 8%-10%, Yb2O3: 5%-6% and Gd2O3: 5%-6%.

4. The thermal protective coating according to any one of claims 1 to 3, characterized in that: The thickness of the NiCoCrAlY first binder layer is 10 μm-30 μm; Preferably, the thickness of the NiCoCrAlY second bonding layer is 10 μm-30 μm; Preferably, the thickness of the CeYSZ first ceramic layer is 30 μm-60 μm; Preferably, the thickness of the GdYbYSZ second ceramic layer is 30 μm-60 μm.

5. The thermal protective coating according to any one of claims 1 to 4, characterized in that: The porosity of the NiCoCrAlY first binder layer is 0.5%-5%; Preferably, the porosity of the NiCoCrAlY second bonding layer is 0.5%-5%; Preferably, the porosity of the CeYSZ first ceramic layer is 2%-7%; Preferably, the porosity of the GdYbYSZ second ceramic layer is 2%-7%.

6. A method for preparing a thermal protective coating according to any one of claims 1 to 5, characterized in that: The preparation method comprises: Spraying the first bonding layer material, the second bonding layer material, the first ceramic layer material and the second ceramic layer material on the surface of the substrate in sequence to form a NiCoCrAlY first bonding layer, a NiCoCrAlY second bonding layer, a CeYSZ first ceramic layer and a GdYbYSZ second ceramic layer in sequence; The second bonding layer material includes NiCoCrAlY metal ceramic composite powder; The NiCoCrAlY metal ceramic composite powder includes CeO2 and Al2O3.

7. The preparation method according to claim 6, characterized in that: In terms of mass percentage, the first bonding layer material includes Co: 20%-26%, Cr: 15%-19%, Al: 11.5%-13.5%, Y: 0.2%-0.7%, and the balance is Ni; Preferably, the method for preparing the NiCoCrAlY metal ceramic composite powder comprises: Wet-milling the raw material of NiCoCrAlY metal ceramic composite powder to obtain NiCoCrAlY composite slurry, spray drying to obtain NiCoCrAlY composite powder, and sintering the NiCoCrAlY composite powder to obtain NiCoCrAlY metal ceramic composite powder; Preferably, the raw materials of the NiCoCrAlY metal ceramic composite powder include, by mass percentage, Ni: 31%-32.5%, Cr: 20%-21.5%, Al: 8%-9%, Y: 0.5%-2%, CeO2: 0.5%-1.5%, Al2O3: 0.5%-1.5%, and the balance is Co; Preferably, in terms of mass percentage, the first ceramic layer material comprises ZrO2: 72%-75%, CeO2: 23%-25% and Y2O3: 2%-3%; Preferably, in terms of mass percentage, the second ceramic layer material comprises: ZrO2: 78%-82%, Y2O3: 8%-10%, Yb2O3: 5%-6% and Gd2O3: 5%-6%.

8. The preparation method according to claim 6 or 7, characterized in that: The spraying method includes supersonic plasma spraying; Preferably, the angle between the spray gun and the substrate surface is 60°-70°; Preferably, during the spraying process, the movement speed of the spray gun is 12 mm / s-20 mm / s; Preferably, before spraying, the substrate is also preheated.

9. The preparation method according to any one of claims 6 to 8, characterized in that: The power of spraying the first bonding layer material and the power of spraying the second bonding layer material are independently 48Kw-52kW; Preferably, the powder feeding rates of spraying the first bonding layer material and spraying the second bonding layer material are independently 5 g / min-10 g / min; Preferably, the power of spraying the first ceramic layer material and the power of spraying the second ceramic layer material are each independently 60kW-65kW; Preferably, the powder feeding rates for spraying the first ceramic layer material and spraying the second ceramic layer material are independently 3 g / min-8 g / min.

10. An application of the thermal protection coating according to any one of claims 1 to 5, characterized in that: The thermal protection coating is applied in the field of engines.

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