Thermal / environmental barrier coating and preparation method thereof

Abstract

The invention relates to a thermal / environmental barrier coating and a preparation method thereof. The coating is of a three-layer structure and sequentially comprises a silicon bonding layer, an ytterbium silicate environment barrier layer and a (RE1xRE21-x) 3TaO7 thermal barrier surface layer from inside to outside. The ytterbium silicate environmental barrier layer is formed by mixing Yb2SiO5 and Yb2Si2O7; a (RE1xRE21-x) 3TaO7 thermal barrier surface layer, wherein x is more than or equal to 0.5 and less than 1; in the preparation method, the high-performance thermal / environmental barrier coating is efficiently prepared by adopting the scheme of synthesizing target powder through a solid-phase reaction, preparing a spraying feed through spray granulation and depositing the coating layer by layer through plasma spraying and utilizing the mechanisms of synergistic improvement of functions of the multi-layer coating, doping modification of rare earth elements and the like. The thermal / environmental barrier coating disclosed by the invention has the advantages of excellent CMAS corrosion resistance, good thermal insulation effect and high layer-to-layer thermal matching, and the service life of the SiCf / SiC composite material can be prolonged under the temperature condition of 1500 DEG C by the thermal / environmental barrier coating.

Description

Technical Field

[0001] The present invention belongs to the field of thermal / environmental barrier coatings, and particularly relates to a thermal / environmental barrier coating and a preparation method thereof. Background Art

[0002] SiC f / SiC composites have the advantages of high temperature resistance, low density, high toughness, high specific strength and specific modulus, etc., and are expected to be applied to the hot-end components of aero-engines with higher thrust-to-weight ratio, lower fuel consumption rate and higher stability. However, SiC f / SiC composites are severely damaged in a high-temperature gas environment containing a large amount of water vapor. The application of environmental barrier coatings (EBCs) on the surface of SiC f / SiC composites can effectively improve their high-temperature water and oxygen corrosion resistance. At present, environmental barrier coatings have developed to the third generation, that is, with silicon as the bonding layer, mullite as the intermediate layer, and rare-earth silicate as the environmental barrier surface layer. With the service combat requirements across the entire territory and all time domains, the high-temperature CMAS corrosion caused by the engine inhaling volcanic ash will generate corrosion products that damage the coating structure of the environmental barrier coating, and at the same time produce local cracks, exacerbating the high-temperature water and oxygen corrosion. High-temperature water and oxygen corrosion and high-temperature CMAS corrosion have become major common problems endangering the safety of aero-engines.

[0003] Based on the severe challenges such as high-temperature water and oxygen corrosion and high-temperature CMAS corrosion faced by current aero-engines, the third-generation environmental barrier coatings can no longer meet the design requirements of new-generation aero-engines. In recent years, researchers committed to seeking breakthroughs have proposed the concept of thermal / environmental barrier coatings, that is, on the basis of the research on the third-generation environmental barrier coatings, a thermal barrier surface layer (TBC) with low thermal conductivity, high melting point, and excellent high-temperature CMAS corrosion resistance is designed and prepared to achieve a breakthrough in the high-temperature CMAS corrosion performance of traditional environmental barrier coatings. Yttria-stabilized zirconia (YSZ), as a typical thermal barrier layer material, has limitations. One is that phase transformation occurs during high-temperature application, resulting in local stress generation and a decrease in fracture toughness; the other is that there is a high-temperature sintering phenomenon, resulting in an increase in grain size, an increase in thermal conductivity, and a decrease in strain tolerance.

[0004] In recent years, new thermal barrier coating materials such as rare-earth zirconates, rare-earth hafniates, rare-earth stannates, rare-earth cerates, rare-earth tantalates, magnetoplumbite structure compounds, garnet structure compounds, etc. have received extensive attention. At present, some researchers have carried out research on using new thermal barrier coating materials as the thermal barrier surface layer materials of thermal / environmental barrier coatings. W.B. Chen et al.

J.Eur.Ceram.Soc.(2022)42:3297-3304

Failure mechanisms of(Gb 0.9 Yb 0.1 ) 2 Zr 2O 7 / Yb 2 SiO 5 / Si thermal / environmental barrier coatings during thermal exposure at 1300℃ / 1400℃

Ceram. Int. (2023) 49:28130-28141

Influence of postheat treatment on the high-temperature performances of multi-layered thermal / environmental barrier coatings on SiC-based composites

[0005] As a new type of thermal barrier coating material, rare-earth tantalates have been systematically studied on their thermophysical properties of rare-earth tantalate bulk materials (RETaO 4 , RE 3 TaO 7 , RETa 3 O 9 ) by L. Chen et al.

Prog. Mater Sci. (2024) 144:101265

Rare-earth tantalates for next-generation thermal barrier coatings

[0006] In summary, for aeroengine SiC fThe third-generation environmental barrier coatings currently applied to the hot-end components of CMCs have the problem of poor resistance to CMAS corrosion. The research on the thermal / environmental barrier coating system designed based on the third-generation environmental barrier coatings is in its infancy. There is little research on high-temperature corrosion resistance, and there are problems such as complex preparation processes, high thermal conductivity, low strain tolerance, low fracture toughness, and thermal mismatch with the environmental barrier layer. Summary of the Invention

[0007] The object of the present invention is to provide a thermal / environmental barrier coating and its preparation method in view of the limitations existing in the current technology. A three-layer thermal / environmental barrier coating is designed and prepared with rare-earth modified tantalate as the thermal barrier surface layer material. The material composition of the thermal barrier surface layer is (RE1 x RE2 1-x ) 3 TaO 7 . In the preparation method, a scheme of synthesizing the target powder by solid-phase reaction, preparing the spraying feed by spray granulation, and depositing the coating layer by layer by plasma spraying is adopted. The mechanisms such as the synergistic improvement of the functions of the multi-layer coating and the doping modification of rare-earth elements are utilized to realize the efficient preparation of a thermal / environmental barrier coating with excellent high-temperature water and oxygen corrosion resistance and high-temperature CMAS corrosion resistance. The present invention has the advantages of excellent CMAS corrosion resistance, good heat insulation effect, and high thermal matching between layers, and can extend the service life of SiC f / SiC composites under the temperature condition of 1500 °C, thereby improving the service stability of the hot-end components of SiC f / SiC composites in aeroengines.

[0008] The technical solution of the present invention is as follows:

[0009] A thermal / environmental barrier coating, the coating has a three-layer structure, and sequentially includes a silicon bonding layer, a ytterbium silicate environmental barrier layer, and (RE1 x RE2 1-x ) 3 TaO 7 thermal barrier surface layer from inside to outside;

[0010] The ytterbium silicate environmental barrier layer is mixed by Yb 2 SiO 5 and Yb 2 Si 2 O 7 The mass ratio of Yb 2 SiO 5 to Yb 2 Si 2 O 7 is 0.25:0.75 to 0.75:0.25;

[0011] The (RE1 x RE21-x ) 3 TaO 7 Thermal barrier coating layer, where 0.5 ≤ x < 1, where RE1 is one of La and Nd, and RE2 is one of Sm, Eu, Gd, Dy, and Ho;

[0012] The thickness of the silicon bonding layer is 50 - 100 μm, the thickness of the ytterbium silicate environmental barrier coating layer is 100 - 150 μm, and the (RE1 x RE2 1-x ) 3 TaO 7 The thickness of the thermal barrier coating layer is 100 - 150 μm.

[0013] The preparation method of the thermal / environmental barrier coating, which comprises the following steps:

[0014] S1. Prepare a slurry by mixing silicon powder with deionized water, binder, and dispersant in proportion, and then prepare spherical powder A by spray drying. Deposit spherical powder A on the SiC f / SiC composite material surface to obtain a silicon bonding layer;

[0015] Among them, the mass ratio is silicon powder: binder: dispersant = 100: 0.4 - 0.6: 1 - 1.5; 50 - 60 g of silicon powder is added to every 100 mL of deionized water;

[0016] S2. According to the atomic ratio in the structural formula Yb 2 SiO 5 , take Yb 2 O 3 and SiO 2 powders and perform ball milling and powder mixing through a planetary ball mill to obtain mixed powder A. Carry out solid-phase reaction of mixed powder A at 1300 - 1400 °C under non-pressure conditions for 1 - 3 h to obtain Yb 2 SiO 5 powder;

[0017] In addition, according to the atomic ratio in the structural formula Yb 2 Si 2 O 7 , weigh Yb 2 O 3 and SiO 2 powders and perform ball milling and powder mixing through a planetary ball mill to obtain mixed powder B. Carry out solid-phase reaction of mixed powder B at 1300 - 1400 °C under non-pressure conditions for 1 - 3 h to obtain Yb 2 Si 2 O 7 powder;

[0018] S3. Take the Yb obtained in step S22 SiO 5 With Yb 2 Si 2 O 7 The powder is in the mass ratio of Yb 2 SiO 5 :Yb 2 Si 2 O 7 =0.25:0.75~0.75:0.25 are mixed, and ball milled by a planetary ball mill to obtain a mixed powder C of 1~5μm;

[0019] S4, preparing a slurry with the mixed powder C in step S3, deionized water, a binder, and a dispersant in proportion, and then preparing a spherical powder B by a spray drying method, and depositing the spherical powder B on the silicon bonding layer in step S1 by a plasma spraying method to obtain an environmental barrier layer;

[0020] The mass ratio is mixed powder: binder: dispersant = 100: 0.4-0.6: 1-1.5; 55-60 g of mixed powder is added to every 100 mL of deionized water;

[0021] S5, according to the molar ratio, RE1 2 O 3 :Ta 2 O 5 :RE2 2 O 3 =2.7~1.5:1:0.3~1.5Weigh RE1 2 O 3 、 2 O 5 and RE2 2 O 3 (RE1 is one of La and Nd, RE2 is one of Sm, Eu, Gd, Dy, and Ho) the powders are ball-milled and mixed by a planetary ball mill to obtain a mixed powder C;

[0022] S6, the mixed powder C in step S5 is subjected to solid phase reaction at 1600-1700°C under pressureless conditions for 2-4 hours, and crushed by a planetary ball mill to obtain 1-5 μm (RE1 x RE2 1-x ) 3 TaO 7 Powder; 0.5≤x<1;

[0023] S7, the step S6 (RE1 x RE2 1-x ) 3 TaO 7The powder is prepared into a slurry with deionized water, a binder, and a dispersant in proportion, and then made into spherical powder C by spray drying. The spherical powder C is deposited on the upper layer of the environmental barrier layer in S5 by plasma spraying to obtain a thermal barrier coating layer.

[0024] Among them, the mass ratio is (RE1 x RE2 1-x ) 3 TaO 7 powder: binder: dispersant = 100: 0.4 - 0.6: 1 - 1.5; 55 - 60 g of (RE1 x RE2 1-x ) 3 TaO 7 powder is added to every 100 mL of deionized water;

[0025] Furthermore, in the above step S1, the process parameters of the spray drying method are: the inlet air temperature is 200 - 400 °C, the outlet air temperature is 100 - 250 °C, the peristaltic pump speed is 30 - 40 revolutions per minute, and the process parameters of the plasma spraying method are: the powder feeding gas is argon, the powder feeding gas flow rate is 3 - 6 L / min, the spraying power is 25 - 35 kW, and the spray gun distance is 80 - 120 mm.

[0026] Furthermore, in the above step S5, the process parameters of the spray drying method are: the inlet air temperature is 200 - 400 °C, the outlet air temperature is 100 - 250 °C, the peristaltic pump speed is 30 - 40 revolutions per minute, and the process parameters of the plasma spraying method are: the powder feeding gas is argon, the powder feeding gas flow rate is 3 - 6 L / min, the spraying power is 35 - 40 kW, and the spray gun distance is 80 - 120 mm.

[0027] Furthermore, in the above step S8, the process parameters of the spray drying method are: the inlet air temperature is 200 - 400 °C, the outlet air temperature is 100 - 250 °C, the peristaltic pump speed is 30 - 40 revolutions per minute, and the process parameters of the plasma spraying method are: the powder feeding gas is argon, the powder feeding gas flow rate is 6 - 9 L / min, the spraying power is 35 - 45 kW, and the spray gun distance is 80 - 120 mm.

[0028] The substantial features of the present invention are:

[0029] What this patent proposes is a thermal barrier coating layer of (RE1 x RE2 1-x ) 3 TaO 7 , Yb 2 SiO 5 and Yb 2 Si 2 O 7Hybrid environmental barrier layer, Si bonding layer. The thermal barrier coating layer and the environmental barrier layer are both prepared by plasma spraying. The spraying powder is prepared through processes such as ball milling and mixing powders, solid-phase reaction, ball milling and crushing, and spray granulation. The Si bonding layer is also prepared by plasma spraying, and its spraying powder is prepared by spray granulating commercial Si powder. The innovation of this patent compared with the closest prior art is as follows: Using (RE1 x RE2 1-x ) 3 TaO 7 as the thermal barrier coating layer material, and there is no relevant literature or patent using this material system for thermal / environmental barrier coatings. The improvements of this patent compared with the closest prior art are as follows: 1. The material selected for the thermal barrier coating is a tantalate material with good thermodynamic and mechanical properties, having a low thermal conductivity and a high strain tolerance at the same time. 2. The composition of the environmental barrier coating selects Yb 2 SiO 5 mixed with Yb 2 Si 2 O 7 , Yb 2 SiO 5 has a thermal expansion coefficient similar to that of the thermal barrier coating layer, and Yb 2 Si 2 O 7 has a thermal expansion coefficient similar to that of the Si bonding layer. By adjusting the ratio of the two, the environmental barrier layer has a moderate thermal expansion coefficient, alleviating the overall thermal mismatch problem of the coating during high-temperature use.

[0030] The beneficial effects of the present invention are as follows:

[0031] 1. Based on the severe challenges such as high-temperature water-oxygen corrosion and high-temperature CMAS corrosion faced by current aeroengines, the present invention provides a thermal / environmental barrier coating. This thermal / environmental barrier coating uses doped tantalate as the thermal barrier coating layer. RE 3 TaO 7 type tantalate has low thermal conductivity, excellent high-temperature phase stability and mechanical properties, and high resistance to CMAS corrosion in new thermal barrier coating materials. By introducing a second rare earth element for doping modification, the strain tolerance and heat insulation performance of the thermal barrier coating layer can be effectively improved. This thermal / environmental barrier layer uses Yb 2 SiO 5 mixed with Yb 2 Si 2 O 7 as the environmental barrier layer. The thermal expansion coefficient of Yb 2 Si 2 O 7 is similar to that of the substrate, and the thermal expansion coefficient of Yb 2 SiO 5 is similar to that of the thermal barrier coating layer, and Yb 2 SiO 5It has excellent water and oxygen corrosion resistance and other characteristics. Yb 2 SiO 5 and Yb 2 Si 2 O 7 are mixed in the proportion of the present invention as the environmental barrier layer. While having good water and oxygen corrosion resistance, it can also effectively alleviate the thermal mismatch problems between the thermal barrier layer and the environmental barrier layer, and between the environmental barrier layer and the bonding layer.

[0032] 2. The present invention provides a method for preparing a thermal / environmental barrier coating. The present invention prepares the spraying feedstocks for the thermal barrier layer, the environmental barrier layer and the bonding layer by means of high-energy ball milling, solid-phase reaction, spraying granulation and other methods for the raw material powders, and obtains the three-layer thermal / environmental barrier coating by plasma spraying layer by layer. The preparation method of this thermal / environmental barrier coating has technical advantages such as simple preparation process, low preparation cost, short preparation time, etc. The prepared thermal / environmental barrier coating has a high-temperature water and oxygen corrosion resistance life of not less than 200 h under the conditions of 1500 °C, a water vapor environment of 90% H 2 0-10% O 2 , a pressure of 1 atm, and a gas flow rate of 8 cm 3 / s, and the number of thermal cycles is not less than 500 times under the conditions of 1450 °C, holding for 5 min, and air cooling for 5 min. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The present invention will be further described below with reference to the drawings and embodiments.

[0034] Figure 1 It is a schematic diagram of the thermal / environmental barrier coating of the thermal barrier layer prepared in Example 1.

[0035] Figure 2 It is the surface XRD pattern of the thermal / environmental barrier coating prepared in Example 1.

[0036] Figure 3 It is the cross-sectional SEM image of the thermal / environmental barrier coating prepared in Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0037] For the convenience of understanding the present invention, the specific implementation manners of the present invention will be further described in detail below in conjunction with the embodiments of the present invention. The described embodiments are part of the embodiments of the present invention, rather than all of the embodiments.

[0038] Figure 1 For the thermal / environmental barrier coating prepared on the surface of the SiC f / SiC composite matrix. As shown in the figure, the coating has a three-layer structure, and sequentially includes a silicon bonding layer 2, a ytterbium silicate environmental barrier layer 3, and (RE1 f / SiC composite matrix 1 from the outside. xRE2 1-x ) 3 TaO 7 Thermal barrier coating layer 4; wherein:

[0039] The ytterbium silicate environmental barrier coating is composed of Yb 2 SiO 5 and Yb 2 Si 2 O 7 mixed, wherein the mass ratio of Yb 2 SiO 5 to Yb 2 Si 2 O 7 is 0.25:0.75 to 0.75:0.25; the (RE1 x RE2 1-x ) 3 TaO 7 thermal barrier coating layer, where 0.5 ≤ x < 1, where RE1 is one of La and Nd, and RE2 is one of Sm, Eu, Gd, Dy, and Ho.

[0040] The described SiC f / SiC composite material is a silicon carbide fiber-reinforced silicon carbide composite material, which is a well-known material, but not limited thereto.

[0041] Example 1

[0042] (1) Prepare SiC f / SiC composite material, the matrix size is 20mm × 20mm × 5mm, ultrasonically clean it with ethanol for 20min, and dry it in an oven at 120°C for 1.5h;

[0043] (2) Select commercially available silicon powder and prepare a slurry with deionized water, binder, and dispersant in proportion. Among them, the mass ratio is silicon powder: binder: dispersant = 100:0.5:1. Add 50g of silicon powder to every 100mL of deionized water, and prepare spherical silicon powder by spray granulation method. Adjust the spray granulation parameters as follows: the inlet air temperature is 250°C, the outlet air temperature is 120°C, and the peristaltic pump speed is 35 revolutions per minute. The particle size of the obtained spherical silicon powder is 30 - 90μm.

[0044] (3) Using atmospheric plasma spraying technology, with spherical silicon powder as the spraying feedstock, prepare a silicon bonding layer on the surface of the SiC f / SiC composite material matrix. Adjust the spraying process parameters as follows: the powder feeding gas is argon, the powder feeding gas flow rate is 5L / min, the spraying power is 30kW, and the spraying distance is 90mm. Obtain a silicon bonding layer with a thickness of about 75μm.

[0045] (4) The raw material powder Yb 2 O 3With SiO 2 Weigh them according to the molar ratio of 1:1, mix them by high-energy ball milling, then heat them up to 1300 °C, keep the temperature for 2 h for solid-phase reaction of the mixed powder, and obtain Yb 2 SiO 5 powder. Then crush it by high-energy ball milling to obtain Yb 2 SiO 5 powder with a particle size of 1 - 5 μm; Weigh the raw material powder Yb 2 O 3 and SiO 2 according to the molar ratio of 1:2, mix them by high-energy ball milling, and carry out solid-phase reaction on the mixed powder at 1300 °C for 2 h to obtain Yb 2 Si 2 O 7 powder. Then crush it by high-energy ball milling to obtain Yb 2 Si 2 O 7 powder.

[0046] (5) Weigh and mix the above-mentioned Yb 2 SiO 5 and Yb 2 Si 2 O 7 according to the mass ratio of 1:1, and prepare them into a slurry with deionized water, binder, and dispersant in proportion. Among them, the mass ratio is Yb 2 SiO 5 -Yb 2 Si 2 O 7 mixed powder: binder: dispersant = 100:0.6:1.2. Add 55 g of Yb 2 SiO 5 -Yb 2 Si 2 O 7 mixed powder to every 100 mL of deionized water, and prepare spherical Yb 2 SiO 5 -Yb 2 Si 2 O 7 composite powder by spray granulation method. Adjust the spray granulation parameters as follows: the inlet air temperature is 250 °C, the outlet air temperature is 120 °C, and the peristaltic pump speed is 35 revolutions per minute. The obtained spherical Yb 2 SiO 5 -Yb 2 Si 2 O 7 composite powder has a particle size of 30 - 90 μm.

[0047] (6) Using atmospheric plasma spraying technology, spherical Yb 2 SiO 5 -Yb 2 Si 2 O 7 composite powder as the spraying feedstock, a ytterbium silicate environmental barrier layer is prepared on the surface of the bonding layer. The spraying process parameters are adjusted as follows: the powder feeding gas is argon, the powder feeding gas flow rate is 6 L / min, the spraying power is 35 kW, and the spraying distance is 80 mm, obtaining an environmental barrier layer with a thickness of about 130 μm.

[0048] (7) Weigh the raw material powders La 2 O 3 , Dy 2 O 3 and Ta 2 O 5 according to the molar ratio of 2.7:0.3:1, mix them by high-energy ball milling, and carry out solid-state reaction on the mixed powder at 1500 °C for 2 h to obtain (La 0.9 Dy 0.1 ) 3 TaO 7 powder, and then crush it by high-energy ball milling to obtain (La 0.9 Dy 0.1 ) 3 TaO 7 powder with a particle size of 1 - 5 μm.

[0049] (8) Prepare the above (La 0.9 Dy 0.1 ) 3 TaO 7 powder into a slurry with deionized water, binder, and dispersant in proportion. Among them, the mass ratio is (La 0.9 Dy 0.1 ) 3 TaO 7 : binder: dispersant = 100:0.5:1.2. Add 60 g of (La 0.9 Dy 0.1 ) 3 TaO 7 powder to every 100 mL of deionized water, and prepare spherical (La 0.9 Dy 0.1 ) 3 TaO 7 powder by spray granulation. Adjust the spray granulation parameters as follows: the inlet air temperature is 250 °C, the outlet air temperature is 120 °C, and the peristaltic pump speed is 35 revolutions per minute. The obtained spherical (La 0.9 Dy 0.1 ) 3 TaO 7 powder has a particle size of 30 - 90 μm.

[0050] (9) Using atmospheric plasma spraying technology, spherical (La 0.9 Dy 0.1 ) 3 TaO 7 powder is used as the spraying feedstock to prepare (La 0.9 Dy 0.1 ) 3 TaO 7 thermal barrier coating layer on the surface of the environmental barrier layer. The spraying process parameters are adjusted as follows: the powder feeding gas is argon, the powder feeding gas flow rate is 7 L / min, the spraying power is 40 kW, and the spraying distance is 80 mm, obtaining a thermal barrier coating layer with a thickness of about 130 μm.

[0051] The XRD pattern of the thermal / environmental barrier coating prepared in Example 1 is as Figure 2 shown. It can be seen that the product of the rare earth-doped modified tantalate thermal barrier coating layer is basically a pure phase.

[0052] The cross-sectional SEM image of the thermal / environmental barrier coating prepared in Example 1 is as Figure 3 shown. It can be seen that there are no obvious delamination cracks between the coatings and between the coating and the substrate, and the bonding is good. The porosity of the coating is 1.7%.

[0053] Perform high-temperature water-oxygen corrosion performance test on the thermal / environmental barrier coating in Example 1:

[0054] Among them, the high-temperature water-oxygen corrosion test conditions are: at 1500 °C, the water vapor environment is 90% H 2 0 - 10% O 2 , the pressure is 1 atm, the gas flow rate is 8 cm 3 / s, until the peeling area of the coating surface is greater than 10%, which is defined as failure. The results show that the high-temperature water-oxygen corrosion resistance life of the thermal / environmental barrier coating in Example 1 is not less than 200 hours.

[0055] Perform thermal cycle test on the thermal / environmental barrier coating in Example 1:

[0056] Among them, the thermal cycle test conditions are: keep warm for 5 min at 1450 °C and then cool naturally for 5 min until the peeling area of the coating surface is greater than 10%, which is defined as failure. The results show that the thermal cycle life of the thermal / environmental barrier coating in Example 1 is 521 times.

[0057] Example 2

[0058] The steps of Example 2 are basically the same as those of Example 1, and the differences are as follows:

[0059] In (7), the raw material powder La 2 O 3 , Dy2 O 3 With Ta 2 O 5 Weigh according to the molar ratio of 2.4:0.6:1, mix by high-energy ball milling, and carry out solid-phase reaction on the mixed powder at 1500 °C for 2 h to obtain (La 0.8 Dy 0.2 ) 3 TaO 7 powder, and then crush it by high-energy ball milling to obtain (La 0.8 Dy 0.2 ) 3 TaO 7 powder with a particle size of 1 - 5 μm.

[0060] In (8), prepare a slurry by mixing (La 0.8 Dy 0.2 ) 3 TaO 7 powder with deionized water, a dispersant, and a binder in a certain proportion. Among them, the mass ratio is (La 0.8 Dy 0.2 ) 3 TaO 7 : binder: dispersant = 100:0.5:1.2. Add 60 g of (La 0.8 Dy 0.2 ) 3 TaO 7 powder to every 100 mL of deionized water, and prepare spherical (La 0.8 Dy 0.2 ) 3 TaO 7 powder by spray granulation. Adjust the spray granulation parameters as follows: the inlet air temperature is 250 °C, the outlet air temperature is 120 °C, and the peristaltic pump speed is 35 revolutions per minute. The obtained spherical (La 0.8 Dy 0.2 ) 3 TaO 7 powder has a particle size of 30 - 90 μm.

[0061] In (9), adopt the atmospheric plasma spraying technology, use spherical (La 0.8 Dy 0.2 ) 3 TaO 7 powder as the spraying feedstock, and prepare (La 0.8 Dy 0.2 ) 3 TaO 7The thermal barrier coating layer, adjusting the spraying process parameters as follows: the powder feeding gas is argon, the powder feeding gas flow rate is 7 L / min, the spraying power is 40 kW, and the spraying distance is 80 mm, to obtain a thermal barrier coating layer with a thickness of about 130 μm.

[0062] Perform high-temperature water-oxygen corrosion performance tests on the thermal / environmental barrier coatings in Example 2:

[0063] Among them, the high-temperature water-oxygen corrosion test conditions are: at 1500 °C, the water vapor environment is 90% H 2 0 - 10% O 2 , the pressure is 1 atm, the gas flow rate is 8 cm 3 / s, until the peeling area on the coating surface is greater than 10%, which is defined as failure. The results show that the high-temperature water-oxygen corrosion resistance life of the thermal / environmental barrier coatings in Example 2 is not less than 200 hours.

[0064] Perform thermal cycle tests on the thermal / environmental barrier coatings in Example 2:

[0065] Among them, the thermal cycle test conditions are: keep warm for 5 min at 1450 °C and cool naturally for 5 min, until the peeling area on the coating surface is greater than 10%, which is defined as failure. The results show that the thermal cycle life of the thermal / environmental barrier coatings in Example 2 is 540 times.

[0066] Example 3

[0067] The steps of Example 3 are basically the same as those of Example 1, the differences are as follows:

[0068] In (7), weigh the raw material powders La 2 O 3 , Dy 2 O 3 and Ta 2 O 5 according to the molar ratio of 2.1:0.9:1, mix them by high-energy ball milling, and perform solid-phase reaction on the mixed powder at 1500 °C for 2 h to obtain (La 0.7 Dy 0.3 ) 3 TaO 7 powder, and then crush it by high-energy ball milling to obtain (La 0.7 Dy 0.3 ) 3 TaO 7 powder with a particle size of 1 - 5 μm.

[0069] In (8), use (La 0.7 Dy 0.3 ) 3 TaO 7The powder is prepared into a slurry with deionized water, a dispersant, and a binder in a certain proportion. Among them, the mass ratio is (La 0.7 Dy 0.3 ) 3 TaO 7 : binder: dispersant = 100:0.5:1.2. 60 g of (La 0.7 Dy 0.3 ) 3 TaO 7 powder is added to every 100 mL of deionized water, and spherical (La 0.7 Dy 0.3 ) 3 TaO 7 powder is prepared by spray granulation. The spray granulation parameters are adjusted as follows: the inlet air temperature is 250 °C, the outlet air temperature is 120 °C, and the peristaltic pump speed is 35 revolutions per minute. The obtained spherical (La 0.7 Dy 0.3 ) 3 TaO 7 powder has a particle size of 30 - 90 μm.

[0070] In (9) kinds, using the atmospheric plasma spraying technology, with spherical (La 0.7 Dy 0.3 ) 3 TaO 7 powder as the spraying feedstock, a (La 0.7 Dy 0.3 ) 3 TaO 7 thermal barrier coating is prepared on the surface of the environmental barrier layer. The spraying process parameters are adjusted as follows: the powder feeding gas is argon, the powder feeding gas flow rate is 7 L / min, the spraying power is 40 kW, and the spraying distance is 80 mm. A thermal barrier coating with a thickness of about 130 μm is obtained.

[0071] The high-temperature water-oxygen corrosion performance of the thermal / environmental barrier coating in Example 3 is tested:

[0072] Among them, the high-temperature water-oxygen corrosion test conditions are: at 1500 °C, the water vapor environment is 90% H 2 0 - 10% O 2 , the pressure is 1 atm, the gas flow rate is 8 cm 3 / s. Until the peeling area of the coating surface is greater than 10%, it is defined as failure. The results show that the high-temperature water-oxygen corrosion resistance life of the thermal / environmental barrier coating in Example 3 is not less than 200 hours.

[0073] The thermal cycle test of the thermal / environmental barrier coating in Example 3 is carried out:

[0074] Among them, the thermal cycle test conditions are as follows: keep warm at 1450 °C for 5 min, and then cool naturally for 5 min until the peeling area of the coating surface is greater than 10%, which is defined as failure. The results show that the thermal cycle life of the thermal / environmental barrier coating in Example 3 is 533 times.

[0075] Example 4 is basically the same as Example 1, except that:

[0076] In (7), weigh the raw material powders La 2 O 3 , Eu 2 O 3 and Ta 2 O 5 according to the molar ratio of 2.7:0.3:1, mix them by high-energy ball milling, and carry out solid-phase reaction on the mixed powder at 1500 °C for 2 h to obtain (La 0.9 Eu 0.1 ) 3 TaO 7 powder, and then crush it by high-energy ball milling to obtain (La 0.9 Eu 0.1 ) 3 TaO 7 powder with a particle size of 1-5 μm.

[0077] In (8), prepare a slurry from (La 0.9 Eu 0.1 ) 3 TaO 7 powder, deionized water, a dispersant, and a binder in proportion. Among them, the mass ratio is (La 0.9 Eu 0.1 ) 3 TaO 7 : binder: dispersant = 100:0.5:1.2. Add 60 g of (La 0.9 Eu 0.1 ) 3 TaO 7 powder to every 100 mL of deionized water, and prepare spherical (La 0.9 Eu 0.1 ) 3 TaO 7 powder by spray granulation. Adjust the spray granulation parameters as follows: the inlet air temperature is 250 °C, the outlet air temperature is 120 °C, and the peristaltic pump speed is 35 revolutions per minute. The obtained spherical (La 0.9 Eu 0.1 ) 3 TaO 7 powder has a particle size of 30-90 μm.

[0078] In (9), use atmospheric plasma spraying technology with spherical (La0.9 Eu 0.1 ) 3 TaO 7 The powder is used as the spraying feedstock to prepare (La 0.9 Eu 0.1 ) 3 TaO 7 thermal barrier coating layer on the surface of the environmental barrier layer. Adjust the spraying process parameters as follows: the powder feeding gas is argon, the powder feeding gas flow rate is 7 L / min, the spraying power is 40 kW, and the spraying distance is 80 mm, to obtain a thermal barrier coating layer with a thickness of about 130 μm.

[0079] Perform high-temperature water-oxygen corrosion performance test on the thermal / environmental barrier coating in Example 4:

[0080] Among them, the high-temperature water-oxygen corrosion test conditions are: at 1500 °C, the water vapor environment is 90% H 2 0 - 10% O 2 , the pressure is 1 atm, the gas flow rate is 8 cm 3 / s, until the peeling area of the coating surface is greater than 10%, which is defined as failure. The results show that the high-temperature water-oxygen corrosion resistance life of the thermal / environmental barrier coating in Example 4 is not less than 200 hours.

[0081] Perform thermal cycle test on the thermal / environmental barrier coating in Example 4:

[0082] Among them, the thermal cycle test conditions are: keep warm for 5 min at 1450 °C and then cool naturally for 5 min, until the peeling area of the coating surface is greater than 10%, which is defined as failure. The results show that the thermal cycle life of the thermal / environmental barrier coating in Example 4 is 518 times.

[0083] Example 5

[0084] The steps of Example 5 are basically the same as those of Example 1, the difference is:

[0085] In (7), weigh the raw material powders La 2 O 3 , Sm 2 O 3 and Ta 2 O 5 according to the molar ratio of 2.7:0.3:1, mix them by high-energy ball milling, and perform solid-phase reaction on the mixed powder at 1500 °C for 2 h to obtain (La 0.9 Sm 0.1 ) 3 TaO 7 powder, and then crush it by high-energy ball milling to obtain (La 0.9 Sm 0.1 ) 3 TaO with a particle size of 1 - 5 μm7 Powder

[0086] In (8), (La 0.9 Sm 0.1 ) 3 TaO 7 powder is prepared into a slurry with deionized water, a dispersant, and a binder in proportion. Among them, the mass ratio is (La 0.9 Sm 0.1 ) 3 TaO 7 : binder: dispersant = 100:0.5:1.2. 60 g of (La 0.9 Er 0.1 ) 3 TaO 7 powder is added to every 100 mL of deionized water. Spherical (La 0.9 Sm 0.1 ) 3 TaO 7 powder is prepared by spray granulation. The spray granulation parameters are adjusted as follows: the inlet air temperature is 250 °C, the outlet air temperature is 120 °C, and the peristaltic pump speed is 35 revolutions per minute. The obtained spherical (La 0.9 Sm 0.1 ) 3 TaO 7 powder has a particle size of 30 - 90 μm.

[0087] In (9), the atmospheric plasma spraying technology is adopted. Using spherical (La 0.9 Sm 0.1 ) 3 TaO 7 powder as the spraying feedstock, a (La 0.9 Sm 0.1 ) 3 TaO 7 thermal barrier coating layer is prepared on the surface of the environmental barrier layer. The spraying process parameters are adjusted as follows: the powder feeding gas is argon, the powder feeding gas flow rate is 7 L / min, the spraying power is 40 kW, and the spraying distance is 80 mm. A thermal barrier coating layer with a thickness of about 130 μm is obtained.

[0088] The high-temperature water-oxygen corrosion performance of the thermal / environmental barrier coating in Example 5 is tested:

[0089] Among them, the high-temperature water-oxygen corrosion test conditions are: at 1500 °C, the water vapor environment is 90% H 2 0 - 10% O 2 , the pressure is 1 atm, the gas flow rate is 8 cm 3 / s. Until the peeling area of the coating surface is greater than 10%, it is defined as failure. The results show that the high-temperature water-oxygen corrosion resistance life of the thermal / environmental barrier coating in Example 5 is not less than 200 hours.

[0090] Perform a thermal cycle test on the thermal / environmental barrier coating in Example 5:

[0091] Among them, the thermal cycle test conditions are: keep warm at 1450 °C for 5 minutes, and cool naturally for 5 minutes until the peeling area of the coating surface is greater than 10%, which is defined as failure. The results show that the thermal cycle life of the thermal / environmental barrier coating in Example 5 is 504 times.

[0092] Example 6

[0093] The steps of Example 6 are basically the same as those of Example 1, except that:

[0094] In (7), weigh the raw material powders La 2 O 3 , Gd 2 O 3 and Ta 2 O 5 according to the molar ratio of 2.7:0.3:1, mix them by high-energy ball milling, and carry out solid-phase reaction on the mixed powder at 1500 °C for 2 hours to obtain (La 0.9 Gd 0.1 ) 3 TaO 7 powder, and then crush it by high-energy ball milling to obtain (La 0.9 Gd 0.1 ) 3 TaO 7 powder with a particle size of 1 - 5 μm.

[0095] In (8), prepare a slurry from (La 0.9 Gd 0.1 ) 3 TaO 7 powder, deionized water, a dispersant, and a binder in proportion. Among them, the mass ratio is (La 0.9 Gd 0.1 ) 3 TaO 7 : binder: dispersant = 100:0.5:1.2. Add 60 g of (La 0.9 Gd 0.1 ) 3 TaO 7 powder to every 100 mL of deionized water, and prepare spherical (La 0.9 Gd 0.1 ) 3 TaO 7 powder by spray granulation. Adjust the spray granulation parameters as follows: the inlet air temperature is 250 °C, the outlet air temperature is 120 °C, and the peristaltic pump speed is 35 revolutions per minute to obtain spherical (La 0.9 Gd 0.1 )3 TaO 7 The particle size of the powder is 30 - 90 μm.

[0096] In (9) kinds, using atmospheric plasma spraying technology, with spherical (La 0.9 Gd 0.1 ) 3 TaO 7 powder as the spraying feedstock, a (La 0.9 Gd 0.1 ) 3 TaO 7 thermal barrier coating layer was prepared on the surface of the environmental barrier layer. The spraying process parameters were adjusted as follows: the powder feeding gas was argon, the powder feeding gas flow rate was 7 L / min, the spraying power was 40 kW, and the spraying distance was 80 mm, obtaining a thermal barrier coating layer with a thickness of about 130 μm.

[0097] The high-temperature water-oxygen corrosion performance of the thermal / environmental barrier coating in Example 6 was tested:

[0098] Among them, the high-temperature water-oxygen corrosion test conditions were: at 1500 °C, the water vapor environment was 90% H 2 0 - 10% O 2 , the pressure was 1 atm, the gas flow rate was 8 cm 3 / s, until the peeling area of the coating surface was greater than 10%, which was defined as failure. The results showed that the high-temperature water-oxygen corrosion resistance life of the thermal / environmental barrier coating in Example 6 was not less than 200 hours.

[0099] The thermal cycle test of the thermal / environmental barrier coating in Example 6 was carried out:

[0100] Among them, the thermal cycle test conditions were: heat preservation for 5 min at 1450 °C and natural cooling for 5 min, until the peeling area of the coating surface was greater than 10%, which was defined as failure. The results showed that the thermal cycle life of the thermal / environmental barrier coating in Example 6 was 514 times.

[0101] Example 7

[0102] Example 7 was basically the same as the steps of Example 1, the difference being that:

[0103] In (7), the raw material powders La 2 O 3 , Ho 2 O 3 and Ta 2 O 5 were weighed according to the molar ratio of 2.7:0.3:1, mixed by high-energy ball milling, and the solid-phase reaction was carried out on the mixed powder at 1500 °C for 2 h to obtain (La 0.9 Ho 0.1 ) 3TaO 7 powder, crushed by high - energy ball milling to obtain (La 0.9 Ho 0.1 ) 3 TaO 7 powder.

[0104] In (8), (La 0.9 Ho 0.1 ) 3 TaO 7 powder is prepared into a slurry with deionized water, a dispersant, and a binder in proportion. Among them, the mass ratio is (La 0.9 Ho 0.1 ) 3 TaO 7 : binder: dispersant = 100:0.5:1.2. 60 g of (La 0.9 Ho 0.1 ) 3 TaO 7 powder is added to every 100 mL of deionized water, and spherical (La 0.9 Ho 0.1 ) 3 TaO 7 powder is prepared by spray granulation. The spray granulation parameters are adjusted as follows: the inlet air temperature is 250 °C, the outlet air temperature is 120 °C, and the peristaltic pump speed is 35 revolutions per minute. The obtained spherical (La 0.9 Ho 0.1 ) 3 TaO 7 powder has a particle size of 30 - 90 μm.

[0105] In (9), the atmospheric plasma spraying technology is adopted, using spherical (La 0.9 Ho 0.1 ) 3 TaO 7 powder as the spraying feedstock to prepare a (La 0.9 Ho 0.1 ) 3 TaO 7 thermal barrier coating layer on the surface of the environmental barrier layer. The spraying process parameters are adjusted as follows: the powder - feeding gas is argon, the powder - feeding gas flow rate is 7 L / min, the spraying power is 40 kW, and the spraying distance is 80 mm. A thermal barrier coating layer with a thickness of about 130 μm is obtained.

[0106] Perform high - temperature water - oxygen corrosion performance tests on the thermal / environmental barrier coatings in Example 7:

[0107] Among them, the high - temperature water - oxygen corrosion test conditions are: at 1500 °C, the steam environment is 90% H 2 0 - 10% O 2, at a pressure of 1 atm and a gas flow rate of 8 cm 3 / s, until the exfoliation area on the coating surface is greater than 10%, which is defined as failure. The results show that the high-temperature water and oxygen corrosion resistance life of the thermal / environmental barrier coating in Example 7 is not less than 200 hours.

[0108] Perform a thermal cycle test on the thermal / environmental barrier coating in Example 7:

[0109] Among them, the thermal cycle test conditions are: keep warm at 1450 °C for 5 min and cool naturally for 5 min, until the exfoliation area on the coating surface is greater than 10%, which is defined as failure. The results show that the thermal cycle life of the thermal / environmental barrier coating in Example 7 is 522 times.

[0110] Example 8

[0111] Example 8 is basically the same as Example 1, except that:

[0112] In (7), weigh the raw material powders Nd 2 O 3 , Dy 2 O 3 and Ta 2 O 5 according to the molar ratio of 2.7:0.3:1, mix them by high-energy ball milling, and perform solid-phase reaction on the mixed powder at 1500 °C for 2 h to obtain (Nd 0.9 Dy 0.1 ) 3 TaO 7 powder, and then crush it by high-energy ball milling to obtain (Nd 0.9 Dy 0.1 ) 3 TaO 7 powder with a particle size of 1-5 μm.

[0113] In (8), prepare a slurry from (Nd 0.9 Dy 0.1 ) 3 TaO 7 powder, deionized water, a dispersant, and a binder. Among them, the mass ratio is (Nd 0.9 Dy 0.1 ) 3 TaO 7 : binder: dispersant = 100:0.5:1.2. Add 60 g of (Nd 0.9 Dy 0.1 ) 3 TaO 7 powder to every 100 mL of deionized water, and prepare spherical (Nd 0.9 Dy 0.1 )3 TaO 7 powder, adjust the spray granulation parameters as follows: the inlet air temperature is 250 °C, the outlet air temperature is 120 °C, and the peristaltic pump speed is 35 revolutions per minute. The obtained spherical (Nd 0.9 Dy 0.1 ) 3 TaO 7 powder has a particle size of 30 - 90 μm.

[0114] Among (9) types, using the atmospheric plasma spraying technology, with spherical (Nd 0.9 Dy 0.1 ) 3 TaO 7 powder as the spraying feedstock, prepare a (Nd 0.9 Dy 0.1 ) 3 TaO 7 thermal barrier coating on the surface of the environmental barrier layer. Adjust the spraying process parameters as follows: the powder feeding gas is argon, the powder feeding gas flow rate is 7 L / min, the spraying power is 40 kW, and the spraying distance is 80 mm. A thermal barrier coating with a thickness of about 130 μm is obtained.

[0115] Conduct a high-temperature water-oxygen corrosion performance test on the thermal / environmental barrier coating in Example 8:

[0116] Among them, the high-temperature water-oxygen corrosion test conditions are: at 1500 °C, the water vapor environment is 90% H 2 0 - 10% O 2 , the pressure is 1 atm, the gas flow rate is 8 cm 3 / s, until the peeling area of the coating surface is greater than 10%, which is defined as failure. The results show that the high-temperature water-oxygen corrosion resistance life of the thermal / environmental barrier coating in Example 7 is not less than 200 hours.

[0117] Conduct a thermal cycle test on the thermal / environmental barrier coating in Example 8:

[0118] Among them, the thermal cycle test conditions are: keep warm for 5 min at 1450 °C and then cool naturally for 5 min, until the peeling area of the coating surface is greater than 10%, which is defined as failure. The results show that the thermal cycle life of the thermal / environmental barrier coating in Example 7 is 546 times.

[0119] Comparative Example 1

[0120] Compare Comparative Example 1 with Example 1. By using the atmospheric plasma spraying technology, sequentially deposit a silicon bonding layer, Yb f / SiC composite material surface, an environmental barrier layer, and a La 2 SiO 5 environmental barrier layer and a La 3 TaO 7 thermal barrier coating, and the specific steps are as follows:

[0121] (1) Prepare SiC f / SiC composite matrix with a size of 20mm×20mm×5mm. Ultrasonically clean it with ethanol for 20 minutes and dry it in an oven at 120°C for 1.5 hours;

[0122] (2) Select commercially available silicon powder and prepare a slurry with deionized water, binder, and dispersant in proportion. Among them, the mass ratio is silicon powder: binder: dispersant = 100:0.5:1. Add 50g of silicon powder to every 100mL of deionized water and prepare spherical silicon powder by spray granulation. Adjust the spray granulation parameters as follows: inlet air temperature is 250°C, outlet air temperature is 120°C, peristaltic pump speed is 35 revolutions per minute, and the particle size of the obtained spherical silicon powder is 30 - 90μm.

[0123] (3) Adopt atmospheric plasma spraying technology, use spherical silicon powder as the spraying feedstock, and prepare a silicon bonding layer on the surface of the SiC f / SiC composite matrix. Adjust the spraying process parameters as follows: powder feeding gas is argon, powder feeding gas flow rate is 5L / min, spraying power is 30kW, spraying distance is 90mm, and obtain a silicon bonding layer with a thickness of about 75μm.

[0124] (4) Weigh the raw material powder Yb 2 O 3 and SiO 2 in a molar ratio of 1:1, mix them by high-energy ball milling, and carry out solid-phase reaction on the mixed powder at 1300°C for 2 hours to obtain Yb 2 SiO 5 powder, and then crush it by high-energy ball milling to obtain Yb 2 SiO 5 powder with a particle size of 1 - 5μm.

[0125] (5) Prepare a slurry with the above Yb 2 SiO 5 powder, deionized water, binder, and dispersant in proportion. Among them, the mass ratio is Yb 2 SiO 5 powder: binder: dispersant = 100:0.6:1.2. Add 55g of Yb 2 SiO 5 mixed powder to every 100mL of deionized water and prepare spherical Yb 2 SiO 5 powder by spray granulation. Adjust the spray granulation parameters as follows: inlet air temperature is 250°C, outlet air temperature is 120°C, peristaltic pump speed is 35 revolutions per minute, and the particle size of the obtained spherical Yb 2 SiO 5 powder is 30 - 90μm.

[0126] (6) The atmospheric plasma spraying technology is adopted, and spherical Yb 2 SiO 5 powder is used as the spraying feedstock to prepare a ytterbium silicate environmental barrier layer on the surface of the bonding layer. The spraying process parameters are adjusted as follows: the powder feeding gas is argon, the powder feeding gas flow rate is 6 L / min, the spraying power is 35 kW, and the spraying distance is 80 mm, obtaining an environmental barrier layer with a thickness of about 130 μm.

[0127] (7) The raw material powders La 2 O 3 and Ta 2 O 5 are weighed according to the molar ratio of 3:1 and mixed by high-energy ball milling. The mixed powder is subjected to solid-phase reaction at 1500 °C for 2 h to obtain La 3 TaO 7 powder, and then crushed by high-energy ball milling to obtain La 3 TaO 7 powder with a particle size of 1 - 5 μm.

[0128] (8) The above La 0.93 TaO 7 powder, deionized water, binder, and dispersant are prepared into a slurry according to a certain proportion. Among them, the mass ratio is La 3 TaO 7 : binder: dispersant = 100:0.5:1.2. 60 g of La 3 TaO 7 powder is added to every 100 mL of deionized water, and spherical La 3 TaO 7 powder is prepared by spray granulation. The spray granulation parameters are adjusted as follows: the inlet air temperature is 250 °C, the outlet air temperature is 120 °C, and the peristaltic pump speed is 35 revolutions per minute. The obtained spherical La 3 TaO 7 powder has a particle size of 30 - 90 μm.

[0129] (9) The atmospheric plasma spraying technology is adopted, and spherical La 3 TaO 7 powder is used as the spraying feedstock to prepare a La 3 TaO 7 thermal barrier coating layer on the surface of the environmental barrier layer. The spraying process parameters are adjusted as follows: the powder feeding gas is argon, the powder feeding gas flow rate is 7 L / min, the spraying power is 40 kW, and the spraying distance is 80 mm, obtaining a thermal barrier coating layer with a thickness of about 130 μm.

[0130] The high-temperature water and oxygen corrosion performance test is carried out on the thermal / environmental barrier coating in Comparative Example 1:

[0131] Among them, the high-temperature water and oxygen corrosion test conditions are as follows: at 1500 °C, the water vapor environment is 90% H 2 0 - 10% O 2 , the pressure is 1 atm, the gas flow rate is 8 cm 3 / s, until the peeling area of the coating surface is greater than 10%, which is defined as failure. The results show that the high-temperature water and oxygen corrosion resistance life of the thermal / environmental barrier coating in Comparative Example 1 is 50 hours.

[0132] The thermal cycle test is carried out on the thermal / environmental barrier coating in Comparative Example 1:

[0133] Among them, the thermal cycle test conditions are as follows: keep warm for 5 min at 1450 °C and cool naturally for 5 min until the peeling area of the coating surface is greater than 10%, which is defined as failure. The results show that the thermal cycle life of the thermal / environmental barrier coating in Comparative Example 1 is 237 times.

[0134] The thermal / environmental barrier coating prepared by the present invention has excellent high-temperature water and oxygen corrosion resistance and thermal cycle resistance under the same conditions.

[0135] The above are only the preferred embodiments of the present invention and cannot be considered as limiting the scope of implementation of the present invention. It should be pointed out that those of ordinary skill in the art in the field of the present technology can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

[0136] Matters not covered by the present invention are well-known technologies.

Claims

1. A thermal / environmental barrier coating, characterized in that the coating is a three-layer structure, which includes, from the inside to the outside, a silicon bonding layer, an ytterbium silicate environmental barrier layer, (RE1 x RE2 1-x )3TaO7 thermal barrier coating; The ytterbium silicate environmental barrier layer is formed by mixing Yb2SiO5 and Yb2Si2O7, wherein the mass ratio of Yb2SiO5 to Yb2Si2O7 is 0.25:0.75 to 0.75:0.25; The (RE1 x RE2 1-x )3TaO7 thermal barrier layer, wherein 0.5≤x<1, wherein RE1 is one of La and Nd, and RE2 is one of Sm, Eu, Gd, Dy, and Ho; The thickness of the silicon bonding layer is 50-100 μm, the thickness of the ytterbium silicate environmental barrier layer is 100-150 μm, and the (RE1 x RE2 1-x )3TaO7 thermal barrier layer thickness is 100~150μm.

2. The method for preparing a thermal / environmental barrier coating according to claim 1, characterized in that the method comprises the following steps: S1. Silicon powder is mixed with deionized water, a binder, and a dispersant in proportion to prepare a slurry, and then a spherical powder A is prepared by a spray drying method. The spherical powder A is deposited on a SiC substrate by a plasma spraying method. f / SiC composite material surface, obtaining a silicon bonding layer; The mass ratio is silicon powder: binder: dispersant = 100: 0.4-0.6: 1-1.5; 50-60 g silicon powder is added to every 100 mL of deionized water; S2. According to the atomic ratio of the structural formula Yb2SiO5, Yb2O3 and SiO2 powders are mixed by ball milling in a planetary ball mill to obtain a mixed powder A, and the mixed powder A is subjected to a solid phase reaction at 1300-1400° C. under pressureless conditions for 1-3 hours to obtain Yb2SiO5 powder; In addition, according to the atomic ratio in the structural formula Yb2Si2O7, Yb2O3 and SiO2 powders are weighed and mixed by ball milling in a planetary ball mill to obtain a mixed powder B, and the mixed powder B is subjected to a solid phase reaction at 1300-1400° C. under a pressureless condition for 1-3 hours to obtain a Yb2Si2O7 powder; S3, mixing the Yb2SiO5 and Yb2Si2O7 powders obtained in step S2 in a mass ratio of Yb2SiO5:Yb2Si2O7=0.25:0.75-0.75:0.25, and grinding them by a planetary ball mill to obtain a mixed powder C of 1-5 μm; S4, preparing a slurry with the mixed powder C in step S3, deionized water, a binder, and a dispersant in proportion, and then preparing a spherical powder B by a spray drying method, and depositing the spherical powder B on the silicon bonding layer in step S1 by a plasma spraying method to obtain an environmental barrier layer; The mass ratio is mixed powder: binder: dispersant = 100: 0.4-0.6: 1-1.5; 55-60 g of mixed powder B is added to every 100 mL of deionized water; S5. According to the molar ratio of RE12O3:Ta2O5:RE22O3=2.7-1.5:1:0.3-1.5, weigh RE12O3, Ta2O5 and RE22O3 (RE1 is one of La and Nd, RE2 is one of Sm, Eu, Gd, Dy and Ho) powders, and mix them by ball milling in a planetary ball mill to obtain mixed powder C; S6, the mixed powder C in step S5 is subjected to solid phase reaction at 1600-1700°C under pressureless conditions for 2-4 hours, and crushed by a planetary ball mill to obtain 1-5 μm (RE1 x RE2 1-x )3TaO7 powder; 0.5≤x<1; S7, the step S6 (RE1 x RE2 1-x )3TaO7 powder is mixed with deionized water, a binder and a dispersant in proportion to form a slurry, and then a spherical powder C is prepared by a spray drying method, and the spherical powder C is deposited on the upper layer of the environmental barrier layer in S5 by a plasma spraying method to obtain a thermal barrier surface layer; Among them, the mass ratio is, (RE1 x RE2 1-x )3TaO7 powder: binder: dispersant = 100: 0.4-0.6: 1-1.5; add 55-60g (RE1) per 100mL deionized water x RE2 1-x )3TaO7 powder.

3. The method for preparing the thermal / environmental barrier coating according to claim 2, characterized in that In the above step S1, the process parameters of the spray drying method are: the inlet air temperature is 200-400°C, the outlet air temperature is 100-250°C, the peristaltic pump speed is 30-40 rpm, and the process parameters of the plasma spraying method are: the powder feeding gas is argon, the powder feeding gas flow rate is 3-6L / min, the spraying power is 25-35kW, and the spray gun distance is 80-120mm.

4. The method for preparing a thermal / environmental barrier coating according to claim 2, characterized in that In the above step S4, the process parameters of the spray drying method are: the inlet air temperature is 200-400°C, the outlet air temperature is 100-250°C, the peristaltic pump speed is 30-40 rpm, and the process parameters of the plasma spraying method are: the powder feeding gas is argon, the powder feeding gas flow rate is 3-6L / min, the spraying power is 35-40kW, and the spray gun distance is 80-120mm.

5. The method for preparing the thermal / environmental barrier coating according to claim 2, characterized in that In the above step S7, the process parameters of the spray drying method are: the inlet air temperature is 200-400°C, the outlet air temperature is 100-250°C, the peristaltic pump speed is 30-40 rpm, and the process parameters of the plasma spraying method are: the powder feeding gas is argon, the powder feeding gas flow rate is 6-9L / min, the spraying power is 35-45kW, and the spray gun distance is 80-120mm.

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