阅读说明：本技术 一种多层结构钡长石环境屏障涂层及其用途和制备方法 (Multi-layer structural celsian environment barrier coating and application and preparation method thereof ) 是由 张晰 张紫琦 刘典 李建章 成来飞 于 2020-12-30 设计创作，主要内容包括：本发明涉及一种耐高温耐腐蚀涂层,具体涉及一种多层结构钡长石环境屏障涂层及其用途和制备方法,以解决现有技术中存在的硅基非氧化物陶瓷的环境屏障涂层材料层间热膨胀系数不匹配,易引起贯穿裂纹、开裂和剥落现象,导致涂层失效、基体材料氧化的问题。该涂层包括粘结层、组合中间层和面层,粘结层为覆盖在基体表面的硅层,组合中间层包括覆盖在硅层上的莫来石层,以及覆盖在莫来石层上的莫来石和掺锶钡长石混合层,面层为覆盖在莫来石和掺锶钡长石混合层上的掺锶钡长石层；粘结层厚度为90-120μm,组合中间层厚度为90-140μm,面层厚度为120-160μm,涂层总厚度≥300μm。该涂层所使用的基体材料为SiC基体、C/SiC复合材料基体或SiC/SiC复合材料基体。(The invention relates to a high-temperature-resistant corrosion-resistant coating, in particular to a barium feldspar environmental barrier coating with a multilayer structure, and application and a preparation method thereof, and aims to solve the problems that the thermal expansion coefficients of material layers of the environmental barrier coating of silicon-based non-oxide ceramic are not matched, through cracks, cracks and peeling phenomena are easily caused, the coating is ineffective, and a base material is oxidized in the prior art. The coating comprises a bonding layer, a combined middle layer and a surface layer, wherein the bonding layer is a silicon layer covering the surface of a substrate, the combined middle layer comprises a mullite layer covering the silicon layer, and a mixed layer of mullite and strontium-doped celsian covering the mullite layer, and the surface layer is a strontium-doped barium feldspar long stone layer covering the mixed layer of mullite and strontium-doped celsian; the thickness of the bonding layer is 90-120 μm, the thickness of the combined intermediate layer is 90-140 μm, the thickness of the surface layer is 120-160 μm, and the total thickness of the coating is more than or equal to 300 μm. The matrix material used by the coating is a SiC matrix, a C/SiC composite matrix or a SiC/SiC composite matrix.)

1. The barium feldspar environment barrier coating with the multilayer structure is characterized in that:

comprises a bonding layer, a combined middle layer and a surface layer;

the bonding layer is a silicon layer covered on the surface of the substrate;

the combined middle layer comprises a mullite layer covered on the silicon layer and a mixed layer of mullite and strontium-doped celsian covered on the mullite layer;

the surface layer is a strontium-doped barium feldspar long stone layer covering the mullite and strontium-doped barium feldspar mixed layer;

the thickness of the bonding layer is 90-120 μm, the thickness of the combined intermediate layer is 90-140 μm, the thickness of the surface layer is 120-160 μm, and the total thickness of the coating is more than or equal to 300 μm.

2. The multi-layer celsian environmental barrier coating of claim 1, wherein:

the material of the mullite and strontium-doped celsian mixed layer is mullite and strontium-doped celsian mixed powder, wherein the mass ratio of the mullite to the strontium-doped celsian is 1: 1-1.2.

3. The multi-layer celsian environmental barrier coating of claim 2, wherein:

in the mullite and strontium-doped celsian mixed powder, the mass ratio of mullite to strontium-doped celsian is 1: 1.

4. the multi-layer celsian environmental barrier coating of any of claims 1 to 3, wherein:

the thickness of the bonding layer is 90-100 μm, the thickness of the combined intermediate layer is 90-110 μm, the thickness of the surface layer is 140 μm, and the total thickness of the coating is 350 μm and 300-.

5. Use of a multi-layer celsian environmental barrier coating according to any of claims 1 to 4, wherein:

the matrix material used is a SiC matrix, a C/SiC composite matrix or a SiC/SiC composite matrix.

6. A preparation method of a multilayer structure celsian environment barrier coating is characterized by comprising the following steps:

1) preparation of the Tie layer

Spraying silicon powder onto the substrate material by a plasma spraying method to form a silicon layer;

during spraying, the total gas amount of the plasma gas is 150-₂60-80% of the total weight of the composition, and H₂The proportion of Ar is 10-30%, and the sum of the three gas proportions is 100%; the carrier gas flow is 4-10 slpm; the spraying distance is 200-250 mm; the powder feeding speed is 30-95 g/min;

2) preparation of composite interlayers

2.1) spraying mullite powder on the silicon layer by adopting a plasma spraying method to form a mullite layer;

when spraying, the total gas amount of the plasma gas is 120-₂60-80% of the total weight of the composition, and H₂The proportion is 20-40%, and the sum of the proportion of the two gases is 100%; the carrier gas flow is 4-10 slpm; the spraying distance is 90-150 mm; the powder feeding speed is 90-155 g/min;

2.2) spraying the mixed powder of the mullite and the strontium-doped celsian on the mullite layer by adopting a plasma spraying method to form a mixed layer of the mullite and the strontium-doped celsian;

when spraying, the total gas amount of the plasma gas is 120-₂60-80% of the total weight of the composition, and H₂The proportion is 20-40%, and the sum of the proportion of the two gases is 100%; the carrier gas flow is 4-10 slpm; the spraying distance is 120-180 mm; the powder feeding speed is 90-155 g/min;

3) preparation of the Top layer

Spraying strontium-doped barium feldspar powder onto the mixed layer of mullite and strontium-doped barium feldspar by adopting a plasma spraying method to form a strontium-doped barium feldspar layer;

when spraying, the total gas amount of the plasma gas is 120-₂60-80% of the total weight of the composition, and H₂The proportion is 20-40%, and the sum of the proportion of the two gases is 100%; the carrier gas flow is 4-10 slpm; the spraying distance is 120-180 mm; the powder feeding rate is 90-155 g/min.

7. The preparation method of the multilayer structure celsian environment barrier coating of claim 6, wherein the preparation method comprises the following steps:

in the step 1), the powder granularity of the silicon powder is 200-600 meshes;

in the step 2.1), the powder granularity of the mullite powder is 200-600 meshes;

in the step 2.2), the powder granularity of the mullite and strontium-doped celsian mixed powder is 400-600 meshes;

in the step 3), the powder granularity of the strontium-doped barium feldspar powder is 200-600 meshes.

8. The method for preparing the multilayer-structure celsian environment barrier coating according to claim 7, wherein the method comprises the following steps:

in the step 1), the total gas amount of the plasma gas is 180-₂70% of H₂The proportion of Ar is 10 percent and 20 percent; the powder feeding rate is 70-90 g/min;

in step 2.1), the total gas amount of the plasma gas is 150-₂70-75% of the total weight of the composition, and H₂The proportion is 25-30%; the powder feeding rate is 120-150 g/min;

in step 2.2), the total gas amount of the plasma gas is 150-₂70-75% of the total weight of the composition, and H₂The proportion is 25-30%; the powder feeding rate is 120-150 g/min;

in step 3), the total gas amount of the plasma gas is 150-₂70-75% of the total weight of the composition, and H₂The proportion is 25-30%; the powder feeding rate is 120-150 g/min.

9. The method for preparing the multilayer-structure celsian environment barrier coating according to claim 8, wherein the method comprises the following steps:

in the step 1), the total gas amount of the plasma gas is 200 lpm; the carrier gas flow was 7 slpm; the powder feeding rate is 85 g/min;

in the step 2.1), the total gas amount of the plasma gas is 170 lpm; the carrier gas flow was 9 slpm; the powder feeding rate is 140 g/min;

in the step 2.2), the total gas amount of the plasma gas is 170 lpm; the carrier gas flow was 8 slpm; the powder feeding rate is 130 g/min;

in the step 3), the total gas amount of the plasma gas is 170 lpm; the carrier gas flow rate was 6 slpm; the powder feeding rate was 105 g/min.

10. The method for preparing the multilayer structure celsian environment barrier coating according to any one of claims 6 to 9, wherein the method comprises the following steps:

in the step 2.2), the mullite and strontium-doped celsian mixed powder is prepared by dry ball milling for 2 hours.

Technical Field

The invention relates to a high-temperature-resistant corrosion-resistant coating, in particular to a multilayer-structure celsian environment barrier coating, and application and a preparation method thereof.

Background

With the trend of development of aero-engines towards high thrust, high efficiency and low oil consumption, the environmental conditions of the aero-engines in service are more severe. In order to realize the breakthrough of the aircraft engine in high thrust-weight ratio and high efficiency, the temperature of the gas in the engine must be increased, and the increase of the temperature of the gas will result in the increase of the surface temperature of the hot-end component of the high-pressure turbine, and at the same time, more severe tests are proposed on the material of the hot-end component of the aircraft engine.

In view of the characteristics that the hot end of the aeroengine is in service in high-temperature and water-oxygen corrosion environments and needs to meet the requirements of fatigue load, ultra-long service life and the like, for the hot end component material of the traditional high-temperature alloy, Thermal Barrier Coatings (TBCs) are often used for carrying out high-temperature protection on the hot end component material, and for a new generation hot end component material, namely ceramic-based composite materials, Environmental Barrier Coatings (EBCs) are adopted to protect the hot end component material from being corroded by water vapor, molten salt, volcanic ash and other environmental factors. The environment barrier coating is an important thermal spraying functional coating, can establish a barrier between a high-temperature structural material and the severe environment (such as corrosive medium, high-speed airflow scouring and the like) of an engine, plays a role in protecting a base material in the severe environment of the engine so as to prevent or reduce the influence of the environment of the engine on the performance of the ceramic matrix composite material, is widely applied to the field of aero-engines, and has important significance for improving the efficiency of the engine, increasing the thrust-weight ratio and further improving the overall performance of the engine.

At present, aiming at the environmental barrier coating of silicon-based non-oxide ceramic, a double-layer coating structure of a mullite bottom layer and a zirconia (YSZ) top layer with yttria partially stabilized is mostly adopted in a working environment with the temperature not higher than 1200 ℃, although the zirconia with yttria partially stabilized has excellent resistance to water-oxygen erosion and can protect the mullite layer, because the thermal expansion coefficient of the coating is about twice of that of the mullite, the coating material has the problem of unmatched thermal expansion coefficients between layers in the actual service process, through cracks are easy to generate, and further, cracking and peeling phenomena are generated, so that the coating fails and the base material is oxidized.

Disclosure of Invention

The invention aims to solve the problems that the thermal expansion coefficients of the material layers of the environment barrier coating of silicon-based non-oxide ceramic are not matched, and the phenomena of through cracks, cracking and peeling are easily caused, so that the coating fails and the base material is oxidized in the prior art, and provides a multilayer-structure celsian environment barrier coating, and application and a preparation method thereof.

The technical scheme adopted by the invention is as follows:

a multilayer structure celsian environment barrier coating is characterized in that:

comprises a bonding layer, a combined middle layer and a surface layer;

the bonding layer is a silicon layer covered on the surface of the substrate;

the combined middle layer comprises a mullite layer covered on the silicon layer and a mixed layer of mullite and strontium-doped celsian covered on the mullite layer;

the surface layer is a strontium-doped barium feldspar long stone layer covering the mullite and strontium-doped barium feldspar mixed layer;

the thickness of the bonding layer is 90-120 μm, the thickness of the combined intermediate layer is 90-140 μm, the thickness of the surface layer is 120-160 μm, and the total thickness of the coating is more than or equal to 300 μm.

Further, the material of the mullite and strontium-doped celsian mixed layer is mullite and strontium-doped celsian mixed powder, wherein the mass ratio of the mullite to the strontium-doped celsian is 1: 1-1.2.

Further, in the mullite and strontium-doped celsian mixed powder, the mass ratio of the mullite to the strontium-doped celsian is 1: 1.

furthermore, the thickness of the bonding layer is 90-100 μm, the thickness of the combined intermediate layer is 90-110 μm, the thickness of the surface layer is 140 μm and the total thickness of the coating is 350 μm and 300-.

The application of the multilayer-structure celsian environment barrier coating is characterized in that:

the matrix material used is a SiC matrix, a C/SiC composite matrix or a SiC/SiC composite matrix.

The preparation method of the multilayer-structure celsian environment barrier coating is characterized by comprising the following steps of:

1) preparation of the Tie layer

Spraying silicon powder onto the substrate material by a plasma spraying method to form a silicon layer;

during spraying, the total gas amount of the plasma gas is 150-₂60-80% of the total weight of the composition, and H₂The proportion of Ar is 10-30%, and the sum of the three gas proportions is 100%; the carrier gas flow is 4-10 slpm; the spraying distance is 200-250 mm; the powder feeding speed is 30-95 g/min;

2) preparation of composite interlayers

2.1) spraying mullite powder on the silicon layer by adopting a plasma spraying method to form a mullite layer;

when spraying, the total gas amount of the plasma gas is 120-₂60-80% of the total weight of the composition, and H₂The proportion is 20-40%, and the sum of the proportion of the two gases is 100%; the carrier gas flow is 4-10 slpm; the spraying distance is 90-150 mm; the powder feeding speed is 90-155 g/min;

2.2) spraying the mixed powder of the mullite and the strontium-doped celsian on the mullite layer by adopting a plasma spraying method to form a mixed layer of the mullite and the strontium-doped celsian;

when spraying, the total gas amount of the plasma gas is 120-₂60-80% of the total weight of the composition, and H₂The proportion is 20-40%, and the sum of the proportion of the two gases is 100%; the carrier gas flow is 4-10 slpm; the spraying distance is 120-180 mm; the powder feeding speed is 90-155 g/min;

3) preparation of the Top layer

Spraying strontium-doped barium feldspar powder onto the mixed layer of mullite and strontium-doped barium feldspar by adopting a plasma spraying method to form a strontium-doped barium feldspar layer;

when spraying, the total gas amount of the plasma gas is 120-₂60-80% of the total weight of the composition, and H₂The proportion is 20-40%, and the sum of the proportion of the two gases is 100%; the carrier gas flow is 4-10 slpm; the spraying distance is 120-180 mm; the powder feeding rate is 90-155 g/min.

Further, in the step 1), the powder particle size of the silicon powder is 200-600 meshes;

in the step 2.1), the powder granularity of the mullite powder is 200-600 meshes;

in the step 2.2), the powder granularity of the mullite and strontium-doped celsian mixed powder is 400-600 meshes;

in the step 3), the powder granularity of the strontium-doped barium feldspar powder is 200-600 meshes.

Further, in step 1), the total gas amount of the plasma gas is 180-₂70% of H₂The proportion of Ar is 10 percent and 20 percent; the powder feeding rate is 70-90 g/min;

in step 2.1), the total gas amount of the plasma gas is 150-₂70-75% of the total weight of the composition, and H₂The proportion is 25-30%; the powder feeding rate is 120-150 g/min;

in step 2.2), the total gas amount of the plasma gas is 150-₂70-75% of the total weight of the composition, and H₂The proportion is 25-30%; the powder feeding rate is 120-150 g/min;

in step 3), the total gas amount of the plasma gas is 150-₂70-75% of the total weight of the composition, and H₂The proportion is 25-30%; the powder feeding rate is 120-150 g/min.

Further, in the step 1), the total gas amount of the plasma gas is 200 lpm; the carrier gas flow was 7 slpm; the powder feeding rate is 85 g/min;

in the step 2.1), the total gas amount of the plasma gas is 170 lpm; the carrier gas flow was 9 slpm; the powder feeding rate is 140 g/min;

in the step 2.2), the total gas amount of the plasma gas is 170 lpm; the carrier gas flow was 8 slpm; the powder feeding rate is 130 g/min;

in the step 3), the total gas amount of the plasma gas is 170 lpm; the carrier gas flow rate was 6 slpm; the powder feeding rate was 105 g/min.

Further, in the step 2.2), the mullite and strontium-doped celsian mixed powder is prepared by dry ball milling for 2 hours.

Compared with the prior art, the invention has the beneficial effects that:

(1) the multilayer-structure celsian environment barrier coating provided by the invention can be used in a working environment at a temperature of not higher than 1200 ℃, the coating material is well combined with a base material, the thermal shock resistance is excellent, and the coating is not easy to crack or peel under the working condition of air-cooling thermal cycle at a temperature of 1200-room temperature;

(2) according to the invention, the silicon layer, the mullite and strontium-doped barium feldspar mixed layer and the strontium-doped barium feldspar long stone layer are respectively used as the bonding layer, the combined middle layer and the surface layer, on one hand, because the thermal expansion coefficients of silicon and the matrix, mullite and silicon, mullite and strontium-doped barium feldspar are similar, the interlayer is not easy to crack due to thermal matching instability; on the other hand, the mullite and strontium-doped celsian mixed layer is prepared between the mullite layer and the strontium-doped barium feldspar layer for transition, so that the thermal expansion coefficient between the layers is in smooth transition, and the phenomenon of cracking and peeling between the coating layers can be effectively avoided; meanwhile, the strontium-doped barium feldspar layer is used as a surface layer, so that the water and oxygen erosion resistance is good, and the overall performance of the coating can be effectively improved;

(3) the moderate total thickness of the coating can not only effectively resist the corrosion of the severe service environment to the surface of the substrate, but also effectively control the defects and the porosity inside the coating;

(4) the coating is prepared on the SiC matrix, the C/SiC composite material matrix or the SiC/SiC composite material matrix, can be used for hot end parts of aero-engines and turbine gas turbines, and effectively improves the overall performance of the engines and the gas turbines.

Detailed Description

The present invention will be described in detail with reference to the following embodiments.

Example one

Preparing a multilayer-structure celsian environment barrier coating on a C/SiC matrix, which comprises the following steps:

1) preparation of the Tie layer

Spraying silicon powder with the powder granularity of 300 meshes onto a base material by adopting a plasma spraying method to form a silicon layer;

when spraying, the total gas amount of the plasma gas is 200lpm, wherein N₂70% of H₂The proportion of Ar is 10 percent and 20 percent; the carrier gas flow was 7 slpm; the spraying distance is 235 mm; the powder feeding rate is 85 g/min; when in useWhen the thickness of the silicon layer reaches 90 mu m, stopping spraying;

2) preparation of composite interlayers

2.1) spraying mullite powder with the powder granularity of 400 meshes onto the silicon layer by adopting a plasma spraying method to form a mullite layer;

when spraying, the total gas amount of the plasma gas is 150lpm, wherein N₂70% of H₂The proportion is 30 percent; the carrier gas flow was 4 slpm; the spraying distance is 130 mm; the powder feeding rate is 150 g/min; when the thickness of the mullite layer reaches 60 mu m, stopping spraying;

2.2) spraying the mixed powder of the mullite and the strontium-doped celsian with the powder granularity of 600 meshes onto the mullite layer by adopting a plasma spraying method to form a mullite and strontium-doped celsian mixed layer; the mullite-strontium-doped celsian mixed powder is prepared by dry ball milling for 2 hours, wherein the mass ratio of the mullite to the strontium-doped celsian is 1: 1;

when spraying, the total gas amount of the plasma gas is 120lpm, wherein N₂60% by weight, H₂The proportion is 40 percent; the carrier gas flow was 8 slpm; the spraying distance is 180 mm; the powder feeding rate is 90 g/min; when the thickness of the mullite and strontium-doped celsian mixed layer reaches 30 mu m, stopping spraying;

3) preparation of the Top layer

Spraying strontium-doped barium feldspar powder with the powder granularity of 350 meshes onto the mixed layer of mullite and strontium-doped barium feldspar by adopting a plasma spraying method to form a strontium-doped barium feldspar layer;

when spraying, the total gas amount of the plasma gas is 170lpm, wherein N₂80% of the total weight of the composition, H₂20 percent of the total weight; the carrier gas flow was 5 slpm; the spraying distance is 135 mm; the powder feeding rate is 100 g/min; and when the thickness of the strontium-doped celsian layer reaches 120 mu m, stopping spraying.

The multilayer-structure celsian environment barrier coating prepared in the embodiment is subjected to thermal shock testing, a sample is placed in a high-temperature test furnace, the temperature is increased to 1200 ℃ along with the furnace, the temperature is kept for 10 minutes, then heating is stopped, the sample is taken out and placed at room temperature, observation is carried out after the temperature of the sample is reduced to the room temperature, the thermal shock times when bubbling, cracking and peeling of the coating occur are recorded, and the test is stopped after the cycle is repeated until the coating peels off. The test results are: when the coating is thermally shocked for 100 times, the coating structure is still complete, and the phenomena of cracking and peeling are not generated, thereby meeting the quality requirement of the coating.

Example two

The preparation method of the multilayer-structure celsian environment barrier coating on the SiC substrate comprises the following specific steps:

1) preparation of the Tie layer

Spraying silicon powder with the powder granularity of 600 meshes onto a base material by adopting a plasma spraying method to form a silicon layer;

when spraying, the total gas amount of the plasma gas is 150lpm, wherein N₂60% by weight, H₂The proportion of Ar is 30 percent and 10 percent; the carrier gas flow was 10 slpm; the spraying distance is 200 mm; the powder feeding rate is 45 g/min; when the thickness of the silicon layer reaches 120 mu m, stopping spraying;

2) preparation of composite interlayers

2.1) spraying mullite powder with the powder granularity of 200 meshes onto the silicon layer by adopting a plasma spraying method to form a mullite layer;

when spraying, the total gas amount of the plasma gas is 120lpm, wherein N₂60% by weight, H₂The proportion is 40 percent; the carrier gas flow was 9 slpm; the spraying distance is 180 mm; the powder feeding rate is 130 g/min; when the thickness of the mullite layer reaches 80 mu m, stopping spraying;

2.2) spraying the mixed powder of the mullite and the strontium-doped celsian with the powder granularity of 400 meshes onto the mullite layer by adopting a plasma spraying method to form a mullite and strontium-doped celsian mixed layer; the mullite-strontium-doped celsian mixed powder is prepared by dry ball milling for 2 hours, wherein the mass ratio of the mullite to the strontium-doped celsian is 1: 1.1;

when spraying, the total gas amount of the plasma gas is 200lpm, wherein N₂80% of the total weight of the composition, H₂The proportion is 20 percent; the carrier gas flow was 5 slpm; the spraying distance is 120 mm; the powder feeding rate is 115 g/min; when the thickness of the mullite and strontium-doped celsian mixed layer reaches 60 mu m, stopping spraying;

3) preparation of the Top layer

Spraying strontium-doped barium feldspar powder with the powder granularity of 500 meshes onto the mixed layer of mullite and strontium-doped barium feldspar by adopting a plasma spraying method to form a strontium-doped barium feldspar layer;

during spraying, the total gas amount of the plasma gas is 140lpm, wherein N₂70% of H₂Accounts for 30 percent; the carrier gas flow was 8 slpm; the spraying distance is 165 mm; the powder feeding rate is 155 g/min; and when the thickness of the strontium-doped celsian layer reaches 160 mu m, stopping spraying.

The multilayer-structure celsian environment barrier coating prepared in the embodiment is subjected to thermal shock testing, a sample is placed in a high-temperature test furnace, the temperature is increased to 1200 ℃ along with the furnace, the temperature is kept for 10 minutes, then heating is stopped, the sample is taken out and placed at room temperature, observation is carried out after the temperature of the sample is reduced to the room temperature, the thermal shock times when bubbling, cracking and peeling of the coating occur are recorded, and the test is stopped after the cycle is repeated until the coating peels off. The test results are: when the coating is thermally shocked for 100 times, the coating structure is still complete, and the phenomena of cracking and peeling are not generated, thereby meeting the quality requirement of the coating.

EXAMPLE III

The preparation method of the multilayer-structure celsian environment barrier coating on the SiC/SiC matrix comprises the following specific steps:

1) preparation of the Tie layer

Spraying silicon powder with the powder granularity of 400 meshes onto a base material by adopting a plasma spraying method to form a silicon layer;

during spraying, the total gas amount of the plasma gas is 190lpm, wherein N₂70% of H₂The proportion of Ar is 20 percent and 10 percent; the carrier gas flow was 5 slpm; the spraying distance is 250 mm; the powder feeding rate is 55 g/min; when the thickness of the silicon layer reaches 100 mu m, stopping spraying;

2) preparation of composite interlayers

2.1) spraying mullite powder with the powder granularity of 350 meshes onto the silicon layer by adopting a plasma spraying method to form a mullite layer;

when spraying, the total gas amount of the plasma gas is 120lpm, wherein N₂65% of the total weight of the composition, H₂The proportion is 35 percent; carrier gas flow of 9slpm(ii) a The spraying distance is 125 mm; the powder feeding rate is 140 g/min; when the thickness of the mullite layer reaches 20 mu m, stopping spraying;

2.2) spraying the mixed powder of the mullite and the strontium-doped celsian with the powder granularity of 500 meshes onto the mullite layer by adopting a plasma spraying method to form a mixed layer of the mullite and the strontium-doped celsian; the mullite-strontium-doped celsian mixed powder is prepared by dry ball milling for 2 hours, wherein the mass ratio of the mullite to the strontium-doped celsian is 1: 1.2, the spraying effect is influenced by the over-high proportion of the strontium-doped celsian;

when spraying, the total gas amount of the plasma gas is 120lpm, wherein N₂80% of the total weight of the composition, H₂The proportion is 20 percent; the carrier gas flow was 5 slpm; the spraying distance is 160 mm; the powder feeding rate is 110 g/min; when the thickness of the mullite and strontium-doped celsian mixed layer reaches 90 mu m, stopping spraying;

3) preparation of the Top layer

Spraying strontium-doped barium feldspar powder with the powder granularity of 600 meshes onto the mixed layer of mullite and strontium-doped barium feldspar by adopting a plasma spraying method to form a strontium-doped barium feldspar layer;

during spraying, the total gas amount of the plasma gas is 160lpm, wherein N₂75% of the total weight of the composition, H₂Accounting for 25 percent; the carrier gas flow rate was 6 slpm; the spraying distance is 130 mm; the powder feeding rate is 120 g/min; and when the thickness of the strontium-doped celsian layer reaches 140 mu m, stopping spraying.

The multilayer-structure celsian environment barrier coating prepared in the embodiment is subjected to thermal shock testing, a sample is placed in a high-temperature test furnace, the temperature is increased to 1200 ℃ along with the furnace, the temperature is kept for 10 minutes, then heating is stopped, the sample is taken out and placed at room temperature, observation is carried out after the temperature of the sample is reduced to the room temperature, the thermal shock times when bubbling, cracking and peeling of the coating occur are recorded, and the test is stopped after the cycle is repeated until the coating peels off. The test results are: when the coating is thermally shocked for 100 times, the coating structure is still complete, and the phenomena of cracking and peeling are not generated, thereby meeting the quality requirement of the coating.