A thermal barrier / environmental barrier integrated protective coating and a method of making the same

Abstract

The application discloses a thermal barrier / environment barrier integrated protective coating and a preparation method thereof, and belongs to the technical field of coating. Yb2SiO5 powder and Al2O3 powder are added into a silicon sol deionized water solution, and a slurry is obtained by stirring; the slurry is uniformly brushed on a substrate by using a wool brush, and the slurry is dried after being brushed on the substrate; S2 is repeated until the weight of the substrate with the slurry is set, and the substrate with the slurry is dried and solidified to obtain a Yb2SiO5-Al2O3 pre-coating layer on the surface of the substrate; the substrate with the Yb2SiO5-Al2O3 pre-coating layer is placed in a reducing atmosphere for heat treatment to obtain a Yb3Al5O 12 / Yb2SiO5 thermal barrier / environment barrier integrated coating. The thermal barrier / environment barrier integrated coating prepared by the preparation method is a Yb3Al5O 12 / Yb2SiO5 coating layer, and the Yb3Al5O 12 / Yb2SiO5 coating layer comprises an internal Yb2SiO5 layer and an external Yb3Al5O 12 layer. The above preparation method solves the technical problems that the existing coating preparation steps are complicated, the preparation period is long, and industrialized production application is difficult.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of coating, and particularly relates to a thermal barrier / environment barrier integrated protective coating and a preparation method thereof. BACKGROUND

[0002] The requirements of high thrust-to-weight ratio and high fuel efficiency of an aero turbine engine promote the development of the light weight, high strength and high temperature stability of the hot end components. Carbon / carbon (C / C) composite material has the unique advantages of low density (<2.0 g / cm 3 ), low thermal expansion coefficient (CTE, 1-2×10 -6 K -1 ) and mechanical properties that do not decrease but increase with the increase of temperature, and is an important candidate material for the turbine engine. The SiC coating based thereon can alleviate the high temperature oxidation problem of the C / C composite material, but when facing the corrosive media such as water vapor and oxygen in the harsh aero engine environment, the protective effect of the SiC coating is poor, so it is necessary to prepare an environmental barrier coating (EBC) to reduce the steam flux reaching the surface of the SiC coating. The durability of the EBC is closely related to the service temperature, and the ultra-high temperature environment (more than 1500℃) before the turbine will accelerate the steam volatilization of the EBC material and the thickening of the thermal growth layer (TGO) on the surface of the SiC, and when the EBC system undergoes high-low temperature steam circulation, the TGO layer will crack due to the continuous phase change of cristobalite and generate tensile stress, and finally lead to the failure of the EBC coating. A large number of studies have shown that the deposition of a low thermal conductivity thermal barrier coating (TBC) on the surface of the EBC can reduce the temperature of the EBC system and reduce the thickening rate of the TGO layer. Therefore, T / EBCs have also attracted extensive attention from researchers.

[0003] Ytterbium silicate (Yb2SiO5, Yb2Si2O7) has been applied to C / C composite EBC material due to its excellent water vapor corrosion resistance, low thermal conductivity (1.6-2.1 W / (m·K)). In addition, ytterbium aluminum garnet (Yb3Al5O 12 , YbAG) is one of the most promising TBC materials due to its low thermal conductivity (1.22 W / (m·K)), thermal expansion coefficient (7.5×10 -6 K -1 ) matched with the EBC material, and very excellent steam corrosion resistance.

[0004] At present, Yb3Al5O 12 / Yb2SiO5 or Yb3Al5O 12The preparation process of the / Yb2Si2O7 coating mainly includes: (1) preparing a ytterbia EBC layer by using atmospheric plasma spraying (APS) or plasma spraying-physical vapor deposition (PS-PVD) technology; (2) preparing an Al film on the surface of the EBC by using a vacuum magnetron sputtering method; and (3) performing multi-step heating treatment on the coating to obtain a Yb3Al5O 12 The TBC protective layer. Although the preparation technology improves the bonding strength between the TBC and the EBC, the preparation steps are complicated, the preparation period is prolonged, and the industrialized production application is not facilitated. SUMMARY

[0005] In order to overcome the shortcomings of the prior art, the purpose of the present application is to provide a thermal barrier / environment barrier integrated protective coating and a preparation method thereof, so as to solve the technical problems of complicated preparation steps, long preparation period and difficult industrialized production application of the existing coating.

[0006] In order to achieve the above purpose, the technical scheme is adopted as follows:

[0007] The present application provides a preparation method of a thermal barrier / environment barrier integrated protective coating, which comprises the following steps:

[0008] S1: adding Yb2SiO5 powder and Al2O3 powder into a silicon sol deionized water solution, and stirring to obtain a slurry;

[0009] S2: uniformly brushing the slurry on the substrate by using a wool brush, and drying after brushing a layer of the slurry;

[0010] S3: repeating S2 until the weight of the substrate with the slurry reaches a set weight, and drying and solidifying the substrate with the slurry to obtain a Yb2SiO5-Al2O3 pre-coating layer on the surface of the substrate;

[0011] S4: placing the substrate with the Yb2SiO5-Al2O3 pre-coating layer in a reducing atmosphere for heat treatment to obtain a Yb3Al5O 12 / Yb2SiO5 thermal barrier / environment barrier integrated coating.

[0012] In the specific implementation process, the Yb2SiO5 powder in the slurry accounts for 92-98% by mass percentage, the Al2O3 powder in the slurry accounts for 2-8% by mass percentage, and the sum of the mass percentages of the Yb2SiO5 powder and the Al2O3 powder in the slurry is 100%.

[0013] In the specific implementation process, the average particle size of the Yb2SiO5 powder is 10 μm, and the average particle size of the Al2O3 powder is 300 nm.

[0014] In the specific implementation process, the mass concentration of the silica sol deionized water solution is 10-50%; the silica sol in the silica sol deionized water solution is an alkaline SiO2 solution, and the mass fraction of SiO2 in the alkaline SiO2 solution is 30%.

[0015] In the specific implementation process, the substrate is a C / C composite material embedded with a SiC coating.

[0016] In the specific implementation process, the drying temperature is 60-80℃, and the drying time is 3-5min.

[0017] The drying and curing temperature is 60-80℃, and the drying and curing time is 12-24h.

[0018] In the specific implementation process, the set weight is 10-15% of the original weight of the substrate.

[0019] In the specific implementation process, the reducing atmosphere is argon or vacuum; the heat treatment temperature is 1500-1580℃, and the heat treatment holding time is 1-3h.

[0020] The application also provides a thermal barrier / environment barrier integrated protective coating.

[0021] In the specific implementation process, the thermal barrier / environment barrier integrated coating is a Yb3Al5O 12 / Yb2SiO5 coating. 12 The overall thickness of the Yb3Al5O 12 / Yb2SiO5 coating is 70-90μm.

[0022] The Yb3Al5O 12 / Yb2SiO5 coating comprises an inner Yb2SiO5 layer and an outer Yb3Al5O 12 layer.

[0023] Compared with the prior art, the application has the following beneficial effects:

[0024] The application provides a preparation method of a thermal barrier / environment barrier integrated protective coating. 12 / Yb2SiO5 powder doped with Al2O3 on the surface of a substrate by using a silica sol as a binder, and then performing heat treatment. 12, the integrated protective coating of internal Yb2SiO5, which greatly shortens the preparation period of T / EBCs. The preparation method provided by the application avoids harmful decomposition products introduced by excessively high spraying temperature and crack defects caused by excessively fast cooling rate of the thermal spraying coating, improves the bonding strength between the environmental barrier coating and the thermal barrier coating and between the environmental barrier coating and the internal coating, and simultaneously provides a new preparation approach for the T / EBCs system.

[0025] Further, the matrix-embedded SiC coating C / C composite material has a rough surface structure, which is beneficial to mechanical engagement with the coating and ensures the interface bonding strength of the matrix and the coating. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 The figure is a flow chart of the preparation method of the thermal barrier / environmental barrier integrated protective coating of the application;

[0027] Figure 2 The figure is the coating prepared in Example 3 of the application, wherein figure (a) is an XRD pattern of the coating; figure (b) is a coating surface; figure (c) is a coating cross section; figure (d) is a local enlarged view of the coating cross section; and figure (e) is an energy spectrum point scanning result;

[0028] Figure 3 The figure is the coating prepared in the preparation process of Comparative Example 1 by using air as the heat treatment atmosphere, wherein figure (a) is an XRD pattern of the coating; and figure (b) is a coating surface;

[0029] Figure 4 The figure is the coating prepared in the preparation process of Comparative Example 2 by using excessively low heat treatment temperature, wherein figure (a) is an XRD pattern of the coating; and figure (b) is a coating surface;

[0030] Figure 5 The figure is the coating prepared in the preparation process of Comparative Example 3 by using excessively high heat treatment temperature, wherein figure (a) is an XRD pattern of the coating; and figure (b) is a coating surface. DETAILED DESCRIPTION

[0031] To enable those skilled in the art to understand the features and effects of the application, the following is a general description and definition of the terms and phrases mentioned in the specification and claims. Unless otherwise specified, all technical and scientific words used in the specification are of the usual meaning understood by those skilled in the art of the application, and in the event of conflict, the definition in the specification shall prevail.

[0032] Theories or mechanisms described and disclosed herein, whether correct or wrong, should not limit the scope of the application in any way, i.e., the content of the application can be implemented without being limited by any specific theory or mechanism.

[0033] Herein, all features defined by a numerical range or a percentage range, such as numerical values, amounts, contents and concentrations, are merely for the sake of brevity and convenience. Accordingly, the description of the numerical range or the percentage range should be considered to have encompassed and specifically disclosed all possible sub-ranges and individual numerical values (including integers and fractions) within the range.

[0034] Herein, unless otherwise specifically stated, "comprise", "include", "contain", "have" or similar terms, encompass both "consist of" and "consist essentially of", for example, "A comprises a" encompasses both "A comprises a and others" and "A comprises only a".

[0035] Herein, for the sake of brevity, all possible combinations of the various technical features in the various embodiments or examples are not described. Therefore, the various technical features in the various embodiments or examples can be combined with each other as long as there is no contradiction, and all possible combinations should be considered as within the scope of the present specification.

[0036] The present application provides a thermal barrier / environmental barrier integrated protective coating and a preparation method thereof.

[0037] In one aspect, the present application provides a preparation method of a thermal barrier / environmental barrier integrated protective coating, wherein the thermal barrier / environmental barrier integrated protective coating is prepared by cold coating brushing combined with heat treatment technology, and the preparation method comprises the following steps:

[0038] S1: adding Yb2SiO5 powder and Al2O3 powder into a silica sol deionized water solution, and stirring to obtain a slurry;

[0039] S2: uniformly brushing the slurry on a substrate by using a wool brush, and drying at a temperature of 60-80℃ for 3-5min after brushing a layer of the slurry;

[0040] S3: repeating S2 until the weight of the substrate with the slurry reaches a set weight (the set weight is 10-15% of the original weight of the substrate), and drying and solidifying the substrate with the slurry at a temperature of 60-80℃ for 12-24h to obtain a Yb2SiO5-Al2O3 pre-coating layer on the surface of the substrate;

[0041] S4: placing the substrate with the Yb2SiO5-Al2O3 pre-coating layer in a reducing atmosphere for heat treatment to obtain a Yb3Al5O12 / Yb2SiO5 thermal barrier / environmental barrier integrated coating. 12 / Yb2SiO5 thermal barrier / environmental barrier integrated coating.

[0042] The preparation method combining cold brushing with heat treatment avoids harmful decomposition products and cracks generated in the process of thermal spraying, and improves the bonding strength between the coating and the substrate and between the coatings.

[0043] In the implementation process, the Yb2SiO5 powder and the Al2O3 powder in the slurry are 92-98% by mass percentage, and the sum of the mass percentages of the Yb2SiO5 powder and the Al2O3 powder is 100%; the average particle sizes of the Yb2SiO5 powder and the Al2O3 powder are 10 microns and 300 nanometers respectively.

[0044] In the implementation process, the substrate is preferably a C / C composite material embedded with a SiC coating, and the C / C composite material embedded with the SiC coating has a rough surface structure, which can further enhance the interface bonding strength between the substrate and the coating.

[0045] In the implementation process, the silicon sol in the silicon sol deionized water solution is used as a binder, wherein the mass concentration of the silicon sol deionized water solution is 10-50%; the silicon sol in the silicon sol deionized water solution is an alkaline SiO2 solution, and the mass fraction of SiO2 in the alkaline SiO2 solution is 30%.

[0046] In the implementation process, the reducing atmosphere is argon or vacuum, and the heat treatment is performed in a tube furnace, and the process of the heat treatment is as follows:

[0047] The substrate with the Yb2SiO5-Al2O3 pre-coating is heated in a tube furnace in a reducing atmosphere at 1500-1580℃ for 1-3 hours.

[0048] As shown in Figure 1 , the application adopts a cold brushing combined with heat treatment technology to prepare a Yb3Al5O 12 / Yb2SiO5 thermal barrier / environment barrier integrated protective coating on the surface of a C / C composite material embedded with a SiC coating. First, Yb2SiO5 powder doped with Al2O3 is cold brushed on the surface of the C / C composite material embedded with the SiC coating by using silicon sol as a binder, and then Al2O3 is diffused to the surface of the coating in a high-temperature reducing atmosphere to generate Yb3Al5O 12 in situ with Yb2SiO5. 12 An integrated protective coating with external Yb3Al5O

[0049] Step 1: Add 92-98% Yb2SiO5 powder and 2-8% Al2O3 powder by mass to a 10-50wt% silica sol deionized water solution and stir thoroughly with a magnetic stirrer to obtain a slurry.

[0050] Step 2: Use a wool brush to apply the slurry evenly to the surface of the C / C composite material with embedded SiC coating. After applying one layer, place the C / C composite material with embedded SiC coating containing the slurry into an oven at 60-80℃ for drying for 3-5 minutes.

[0051] Step 3: Repeat step 2 until the weight of the C / C composite material with embedded SiC coating increases by 10-15% of the original weight of the C / C composite material with embedded SiC coating. Then, place it in an oven at 60-80℃ for drying and curing for 12-24 hours. A Yb2SiO5-Al2O3 pre-coating is obtained on the surface of the C / C composite material with embedded SiC coating.

[0052] Step 4: The C / C composite material with an embedded SiC coating and a Yb2SiO5-Al2O3 pre-coating is held in a tubular heat treatment furnace at a reducing atmosphere of 1500-1580℃ for 1-3 hours to obtain a Yb3Al5O3 composite material with a thickness of 70-90 μm. 12 / Yb2SiO5 thermal barrier / environmental barrier integrated protective coating.

[0053] In another aspect, the present invention provides an integrated thermal barrier / environmental barrier protective coating prepared according to the above preparation method, wherein the integrated thermal barrier / environmental barrier coating is Yb3Al5O 12 / Yb2SiO5 coating, Yb3Al5O 12 The Yb2SiO5 coating consists of an inner Yb2SiO5 layer and an outer Yb3Al5O layer. 12 layer.

[0054] Specifically, Yb3Al5O 12 The overall thickness of the Yb2SiO5 thermal barrier / environmental barrier integrated coating is 70-90μm.

[0055] Yb3Al5O prepared by cold coating combined with reducing atmosphere heat treatment technology 12 The Yb2SiO5 thermal barrier / environmental barrier integrated protective coating has high density.

[0056] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0057] The following examples use apparatus and equipment that are conventional in the art. The experimental methods in the following examples, unless otherwise specified, are generally conducted under conventional conditions, or under conditions recommended by the manufacturer. The following examples use various raw materials, unless otherwise specified, which are conventional commercially available products, and which are of conventional specifications in the art. In the specification of the present application and in the following examples, unless otherwise specified, "%" means percent by weight, "parts" means parts by weight, and ratios are by weight.

[0058] Example 1:

[0059] Step 1: Add 95% by mass of Yb2SiO5 powder and 5% of Al2O3 powder into a 20wt% silicon sol deionized water solution, and after stirring under a magnetic stirrer for 10 h, a slurry is obtained;

[0060] Step 2: Use a wool brush to dip the slurry and evenly brush it on the surface of the SiC-embedded C / C composite material, and after brushing a layer, the SiC-embedded C / C composite material with the slurry is placed in an oven at 60°C for drying for 5 min;

[0061] Step 3: Repeat the operation of Step 2 until the SiC-embedded C / C composite material is increased by 10%, and then it is placed in an oven at 60°C for drying and curing for 24 h, and a Yb2SiO5-Al2O3 pre-coating layer is obtained on the surface of the SiC-embedded C / C composite material;

[0062] Step 4: The SiC-embedded C / C composite material with the Yb2SiO5-Al2O3 pre-coating layer is placed in a tube heat treatment furnace at 1500°C under argon protection for 3 h, and a Yb3Al5O12 / Yb2SiO5 thermal barrier / environment barrier integrated protective coating layer with an average thickness of 70 μm is obtained. 12 / Yb2SiO5 thermal barrier / environment barrier integrated protective coating layer.

[0063] Example 2:

[0064] Step 1: Add 98% by mass of Yb2SiO5 powder and 2% of Al2O3 powder into a 50wt% silicon sol deionized water solution, and after stirring under a magnetic stirrer for 6 h, a slurry is obtained;

[0065] Step 2: Use a wool brush to dip the slurry and evenly brush it on the surface of the SiC-embedded C / C composite material, and after brushing a layer, the SiC-embedded C / C composite material with the slurry is placed in an oven at 80°C for drying for 3 min;

[0066] Step 3: Repeat Step 2 until the C / C composite material with embedded SiC coating is increased by 15%, then put it into the oven at 80℃ for drying and curing for 18h, and a Yb2SiO5-Al2O3 pre-coating layer is obtained on the surface of the C / C composite material with embedded SiC coating;

[0067] Step 4: Put the C / C composite material with embedded SiC coating and Yb2SiO5-Al2O3 pre-coating layer into a vacuum tube furnace at 1580℃ for 1h, and a Yb3Al5O 12 / Yb2SiO5 thermal barrier / environmental barrier integrated protective coating is obtained.

[0068] Example 3:

[0069] Step 1: Add 95wt% Yb2SiO5 powder and 5wt% Al2O3 powder into a 40wt% silica sol deionized water solution, and stir under a magnetic stirrer for 8h to obtain a slurry;

[0070] Step 2: Use a wool brush to dip the slurry and evenly brush it on the surface of the C / C composite material with embedded SiC coating, and then put the C / C composite material with embedded SiC coating and slurry into an oven at 70℃ for drying for 4min;

[0071] Step 3: Repeat Step 2 until the C / C composite material with embedded SiC coating is increased by 15%, then put it into the oven at 70℃ for drying and curing for 24h, and a Yb2SiO5-Al2O3 pre-coating layer is obtained on the surface of the C / C composite material with embedded SiC coating;

[0072] Step 4: Put the C / C composite material with embedded SiC coating and Yb2SiO5-Al2O3 pre-coating layer into a tube furnace at 1550℃ under argon protection for 2h, and a Yb3Al5O 12 / Yb2SiO5 thermal barrier / environmental barrier integrated protective coating is obtained.

[0073] Example 4:

[0074] Step 1: Add 92wt% Yb2SiO5 powder and 8wt% Al2O3 powder into a 10wt% silica sol deionized water solution, and stir under a magnetic stirrer for 10h to obtain a slurry;

[0075] Step 2: Use a wool brush to dip the slurry and evenly brush it on the surface of the C / C composite material with embedded SiC coating, and then put the C / C composite material with embedded SiC coating and slurry into an oven at 60℃ for drying for 5min;

[0076] Step 3: Repeat Step 2 until the C / C composite material with embedded SiC coating is increased by 10%, then it is placed in an oven at 60°C for drying and curing for 24h, and a Yb2SiO5-Al2O3 pre-coating is obtained on the surface of the C / C composite material with embedded SiC coating;

[0077] Step 4: The C / C composite material with embedded SiC coating and Yb2SiO5-Al2O3 pre-coating is placed in a tube furnace at 1500°C for 3h under argon protection, and a Yb3Al5O 12 / Yb2SiO5 thermal barrier / environmental barrier integrated protective coating is obtained.

[0078] Example 5:

[0079] Step 1: Yb2SiO5 powder with a mass percentage of 93% and 7% Al2O3 powder are added to a 15wt% silica sol deionized water solution, and the slurry is obtained after being stirred under a magnetic stirrer for 6h;

[0080] Step 2: The slurry is evenly brushed on the surface of the C / C composite material with embedded SiC coating using a wool brush, and after brushing a layer, the C / C composite material with embedded SiC coating and slurry is placed in an oven at 80°C for drying for 3min;

[0081] Step 3: Repeat Step 2 until the C / C composite material with embedded SiC coating is increased by 15%, then it is placed in an oven at 80°C for drying and curing for 12h, and a Yb2SiO5-Al2O3 pre-coating is obtained on the surface of the C / C composite material with embedded SiC coating;

[0082] Step 4: The C / C composite material with embedded SiC coating and Yb2SiO5-Al2O3 pre-coating is placed in a vacuum tube furnace at 1580°C for 1h, and a Yb3Al5O 12 / Yb2SiO5 thermal barrier / environmental barrier integrated protective coating is obtained.

[0083] Example 6:

[0084] Step 1: Yb2SiO5 powder with a mass percentage of 94% and 6% Al2O3 powder are added to a 30wt% silica sol deionized water solution, and the slurry is obtained after being stirred under a magnetic stirrer for 8h;

[0085] Step 2: The slurry is evenly brushed on the surface of the C / C composite material with embedded SiC coating using a wool brush, and after brushing a layer, the C / C composite material with embedded SiC coating and slurry is placed in an oven at 70°C for drying for 4min;

[0086] Step 3: Repeat Step 2 until the C / C composite material with embedded SiC coating is increased by 10%, then put it into the oven at 70℃ for drying and curing for 24h, and a Yb2SiO5-Al2O3 pre-coating layer is obtained on the surface of the C / C composite material with embedded SiC coating;

[0087] Step 4: Put the C / C composite material with embedded SiC coating and Yb2SiO5-Al2O3 pre-coating layer into a tube furnace at 1550℃ in argon atmosphere for 2h, and obtain a Yb3Al5O12 thermal barrier / environmental barrier integrated protective coating with an average thickness of 70μm. 12 / Yb2SiO5 thermal barrier / environmental barrier integrated protective coating.

[0088] Comparative Example 1:

[0089] The heat treatment process of Comparative Example 1 is 1500℃ in air atmosphere for 2h.

[0090] Step 1: Add 94wt% Yb2SiO5 powder and 6wt% Al2O3 powder into a 50wt% silica sol deionized water solution, and fully stir under a magnetic stirrer for 10h to obtain a slurry;

[0091] Step 2: Use a wool brush to dip the slurry and evenly brush it on the surface of the C / C composite material with embedded SiC coating, and then put the C / C composite material with embedded SiC coating and slurry into an oven at 70℃ for drying for 4min;

[0092] Step 3: Repeat Step 2 until the C / C composite material with embedded SiC coating is increased by 10%, then put it into the oven at 70℃ for drying and curing for 24h, and a Yb2SiO5-Al2O3 pre-coating layer is obtained on the surface of the C / C composite material with embedded SiC coating;

[0093] Step 4: Put the C / C composite material with embedded SiC coating and Yb2SiO5-Al2O3 pre-coating layer into a tube furnace at 1550℃ in argon atmosphere for 2h, and obtain a Yb3Al5O12 thermal barrier / environmental barrier integrated protective coating with an average thickness of 70μm. 12 / Yb2SiO5 thermal barrier / environmental barrier integrated protective coating.

[0094] Comparative Example 2:

[0095] The heat treatment process of Comparative Example 1 is 1500℃ in air atmosphere for 2h.

[0096] Step 1: Add 94wt% Yb2SiO5 powder and 6wt% Al2O3 powder into a 50wt% silica sol deionized water solution, and fully stir under a magnetic stirrer for 10h to obtain a slurry;

[0097] Step 2: Use a wool brush to apply the slurry evenly to the surface of the C / C composite material with embedded SiC coating. After applying one layer, place the C / C composite material with embedded SiC coating containing the slurry into an oven at 80℃ and dry for 3 minutes.

[0098] Step 3: Repeat step 2 until the weight gain of the C / C composite material with embedded SiC coating is 13%. Then, place it in an oven at 80°C for drying and curing for 18 hours. A Yb2SiO5-Al2O3 pre-coating is obtained on the surface of the C / C composite material with embedded SiC coating.

[0099] Step 4: The C / C composite material with embedded SiC coating and Yb2SiO5-Al2O3 pre-coating is heated in an argon atmosphere at 1400℃ for 2 hours to obtain an unsintered Yb2SiO5-Al2O3 porous coating.

[0100] Comparative Example 3:

[0101] The heat treatment process for Comparative Example 3 was to keep the sample in an argon atmosphere at 1600℃ for 2 hours.

[0102] Step 1: Add 95% Yb2SiO5 powder and 5% Al2O3 powder by mass percentage to a 40wt% silica sol deionized water solution, and stir thoroughly for 10 hours under a magnetic stirrer to obtain a slurry.

[0103] Step 2: Use a wool brush to apply the slurry evenly to the surface of the C / C composite material with embedded SiC coating. After applying one layer, place the C / C composite material with embedded SiC coating containing the slurry into an oven at 60℃ and dry for 5 minutes.

[0104] Step 3: Repeat step 2 until the weight gain of the C / C composite material with embedded SiC coating is 10%. Then, place it in an oven at 60°C for drying and curing for 24 hours. A Yb2SiO5-Al2O3 pre-coating is obtained on the surface of the C / C composite material with embedded SiC coating.

[0105] Step 4: The embedded SiC-coated carbon / carbon composite material with a Yb2SiO5-Al2O3 pre-coating is held at 1600℃ in an argon atmosphere for 2 hours to obtain Yb3Al5O3 with more crack defects. 12 / Yb2SiO5 thermal barrier / environmental barrier integrated coating.

[0106] like Figure 2 As shown in Figure (a), the XRD pattern illustrates that the coating surface is composed of Yb3Al5O 12The phase composition meets the material design requirements for thermal barrier coatings; Figure (b) is a backscatter image of the coating surface, showing no obvious cracks or pores; Figure (c) is a backscatter image of the coating cross section, showing that the integrated thermal barrier / environmental barrier coating is tightly bonded to the SiC inner coating, and there is no obvious interface between the thermal barrier coating and the environmental barrier coating; Figure (d) is a magnified image of the coating cross section, and combined with the spot scan results, it can be seen that the thickness of the thermal barrier coating is about 10 μm, and the thickness of the environmental barrier coating is about 60-80 μm.

[0107] like Figure 3 The microstructure of the coating after air heat treatment at 1500℃ for 2 hours is shown. The main phases on the coating surface are Yb2Si2O7 and Yb3Al5O. 12 The coating surface contains large pores and cracks. Corrosive gases in the environment during the coating's service life can quickly diffuse into the substrate through these defects, leading to rapid substrate failure.

[0108] like Figure 4 The microstructure of the coating after heat treatment in an argon atmosphere at 1500℃ for 2 hours is shown. According to XRD, this temperature is insufficient to allow Yb2SiO5 and Al2O3 to react in situ. The coating does not meet the phase requirements of the design coating, and the coating surface contains a large number of pores, which provide diffusion channels for corrosive gases.

[0109] like Figure 5 The microstructure of the coating after heat treatment in an argon atmosphere at 1600℃ for 2 hours is shown. Although the phase on the surface of the coating is the designed thermal barrier coating material, the surface of the coating contains a large number of wide cracks due to the reaction sintering at excessively high temperature, which is not conducive to protecting the substrate.

[0110] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A method of producing a thermal barrier / environmental barrier integrated protective coating, characterized by, The method comprises the following steps: S1: adding Yb2SiO5 powder and Al2O3 powder into a silicon sol deionized water solution, and stirring to obtain a slurry; S2: evenly brushing the slurry on a substrate by using a wool brush, and drying after brushing a layer of the slurry; S3: repeating S2 until the weight of the substrate with the slurry reaches a set weight, and drying and solidifying the substrate with the slurry to obtain a Yb2SiO5-Al2O3 pre-coating layer on the surface of the substrate; S4: the substrate with Yb2SiO5-Al2O3 pre-coating is placed under argon or vacuum for heat treatment, obtaining Yb3Al5O 12 / Yb2SiO5 thermal barrier / environmental barrier integrated coating; The temperature of the heat treatment is 1500-1580℃, and the holding time of the heat treatment is 1-3h.

2. The method of claim 1, wherein the method further comprises: The mass percentage of the Yb2SiO5 powder in the slurry is 92-98%, the mass percentage of the Al2O3 powder in the slurry is 2-8%, and the sum of the mass percentages of the Yb2SiO5 powder and the Al2O3 powder in the slurry is 100%.

3. The method of claim 1 or 2, wherein The average particle size of the Yb2SiO5 powder is 10μm, and the average particle size of the Al2O3 powder is 300nm.

4. The method of claim 1, wherein the thermal and environmental barrier coating is prepared by a process comprising: The mass concentration of the silicon sol deionized water solution is 10-50%.

5. The method of claim 1, wherein the thermal and environmental barrier coating is prepared by a process comprising: The substrate is a C / C composite material embedded with a SiC coating.

6. The method of claim 1, wherein the thermal and environmental barrier coating is prepared by a process comprising: In S2, the drying temperature is 60-80℃, and the drying time in S2 is 3-5min. In S3, the drying and solidifying temperature is 60-80℃, and the drying and solidifying time in S3 is 12-24h.

7. The method of claim 1, wherein the method further comprises: The set weight is 10-15% of the original weight of the substrate.

8. A thermal and environmental barrier integrated protective coating prepared by the preparation method according to any one of claims 1 to 7.

9. The thermal / environmental barrier coating of claim 8, wherein, The integrated thermal barrier / environmental barrier coating is Yb3Al5O 12 / Yb2SiO5 coating, Yb3Al5O 12 The overall thickness of the Yb2SiO5 coating is 70-90 μm. The Yb3Al5O 12 / Yb2SiO5coating includes an inner Yb2SiO5layer and an outer Yb3Al5O 12 layer.

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