A high-temperature resistant, self-lubricating, low-friction sealing coating material and its preparation method

Abstract

This invention provides a method for preparing a high-temperature resistant, self-lubricating, and low-friction sealing coating material. The method comprises the following steps: S1, spraying NiCoCrAlY alloy powder onto the surface of an alloy substrate using plasma spraying, supersonic flame spraying, laser cladding, or arc cladding to form a Ni-based bonding layer; S2, preparing 8YSZ powder onto the surface of the Ni-based bonding layer using laminar plasma spraying or electron beam physical vapor deposition to form a first ceramic coating; S3, further preparing a first co-doped zirconium oxide system (LZO, LCO, and GZO in a mass ratio of 1:1:1) or a second co-doped zirconium oxide system (MoS2 and CaF2 in a mass ratio of 10:3:7) onto the surface of the first ceramic coating using laminar plasma spraying or electron beam physical vapor deposition to form a second ceramic coating. The resulting sealing coating exhibits high-temperature resistance, self-lubrication, and low-friction properties.

Description

Technical Field

[0001] This invention relates to the field of composite coating technology, and in particular to a high-temperature resistant, self-lubricating, low-friction sealing coating material and its preparation method. Background Technology

[0002] High-temperature alloys, with their excellent high-temperature mechanical properties, oxidation resistance, and corrosion resistance, are widely used in gas turbines, thermal power generation, and the nuclear energy industry. However, with the development of aerospace engine and gas turbine technology, higher requirements have been placed on the sealing of the gaps between blade tips and compressor and turbine castings. Abrasive sealing coatings are commonly used for the gas path sealing of aircraft turbine engines to reduce the gaps between blade tips and compressor and turbine castings, thereby protecting the blades, reducing interstage leakage, and improving engine efficiency. They are currently widely used in the aerospace field. The preparation of sealing coatings is a key technology for turbine engine gas path sealing.

[0003] To prevent coating peeling, abrasive sealing coatings must possess not only relatively high bonding strength but also good overall performance. They need to be sufficiently "hard" to ensure normal operation under high-temperature, high-speed airflow erosion; this requirement is primarily achieved through the metallic phases (Al-based, Cu-based, Ni-based, Co-based, etc.) in the sealing coating, which provide support. Simultaneously, they need to be sufficiently "soft" to preferentially wear down when rubbing against rotor components, preventing blade damage from scraping; this requirement is mainly achieved through the non-metallic phases (graphite, boron nitride, polymer materials, etc.) and porosity in the sealing coating. Porosity effectively reduces the coating's hardness, while the non-metallic phases provide lubrication.

[0004] As the temperature of the combustion gas continues to rise, higher requirements are placed on the high-temperature resistance of the sealing coating. At the same time, due to the functional characteristics of the sealing coating, on the one hand, the sealing coating needs to be wear-resistant, and on the other hand, the coating must not cause friction damage to the turbine components. This places new and higher demands on wear-resistant sealing coatings. Summary of the Invention

[0005] To address the aforementioned problems in the existing technology, this invention provides a high-temperature resistant, low-friction double-layer ceramic protective coating material and its preparation method. By designing the material and preparation technology of the double-layer gradient composite functional coating, a double-layer ceramic protective coating material (sealing coating) with high temperature resistance up to 1300℃ and possessing high temperature resistance, self-lubrication, and low friction properties is prepared.

[0006] The specific details of the invention are as follows:

[0007] In a first aspect, the present invention provides a method for preparing a high-temperature resistant, self-lubricating, low-friction sealing coating material, the method comprising the following preparation steps:

[0008] S1. NiCoCrAlY alloy powder is sprayed onto the surface of the alloy substrate using plasma spraying, supersonic flame spraying, laser cladding equipment or arc cladding equipment to form a Ni-based bonding layer.

[0009] S2. 8YSZ powder is prepared on the surface of the Ni-based adhesive layer by atmospheric laminar plasma spraying or electron beam physical vapor deposition technology to form a first ceramic coating.

[0010] S3. Further, a first combined powder of LZO, LCO and GZO in a mass ratio of 1:1:1, or a second combined powder of the first combined powder, MoS2 and CaF2 in a mass ratio of 10:3:7, is prepared on the surface of the first ceramic coating to form a second ceramic coating by atmospheric laminar plasma spraying or electron beam physical vapor deposition.

[0011] Optionally, in step S1, the thickness of the Ni-based adhesive layer is 1-150 μm.

[0012] Optionally, in step S2, the particle size of the 8YSZ powder is 37-69 μm.

[0013] Optionally, in step S2, the powder feeding rate of the 8YSZ powder is 3-4 g / min.

[0014] Optionally, in step S2, the thickness of the first ceramic coating is 200-300 μm;

[0015] The microstructure of the first ceramic coating has a vertical crack structure with a density of 2-4 cracks per millimeter.

[0016] Optionally, in step S3, the particle size of the first combined powder, MoS2, and CaF2 is 40-80 μm.

[0017] Optionally, in step S3, the thickness of the second ceramic coating is 100-150 μm;

[0018] The microstructure of the second ceramic coating has a vertical crack structure with a density of 2-4 cracks per millimeter.

[0019] Optionally, the operating parameters of the atmospheric laminar plasma spraying technology are:

[0020] The volume ratio of nitrogen to argon is 7:3;

[0021] The operating current is 120-160A;

[0022] Output power is 15-30kW;

[0023] The spraying distance is 200-300mm;

[0024] The spraying speed is 0.4-0.8 m / s;

[0025] The spraying interval is 3-8mm.

[0026] Optionally, the operating parameters of the atmospheric laminar plasma spraying technology are:

[0027] The volume ratio of nitrogen to argon is 7:3;

[0028] The operating current is 160A;

[0029] The output power is 25-26kW;

[0030] The spraying distance is 250mm;

[0031] The spraying speed is 0.4 m / s;

[0032] The spraying interval is 4mm.

[0033] Optionally, the alloy matrix includes: high-temperature alloy K456 or Incoloy M956.

[0034] Optionally, the alloy substrate surface is an alloy substrate surface that has undergone degreasing and sandblasting treatment.

[0035] In a second aspect, the present invention provides a high-temperature resistant, self-lubricating, low-friction sealing coating material obtained by the preparation method described in the first aspect above, wherein the high-temperature resistant, self-lubricating, low-friction sealing coating material comprises: a first ceramic coating and a second ceramic coating sequentially located on the surface of an alloy substrate having an adhesive layer.

[0036] Compared with the prior art, the present invention has the following advantages:

[0037] This invention provides a sealing coating material and preparation method that is prepared under atmospheric conditions and has high temperature resistance, self-lubrication, and low friction. The sealing coating has a double-layer ceramic structure. The bottom ceramic layer is 8YSZ ceramic, and the top ceramic layer is mainly composed of any one of the following component systems: (1) LZO+LCO+GZO co-doped zirconium oxide system; (2) MoS2, CaF2, La, Ce, Gd co-doped zirconium oxide system. Due to the high temperature resistance, self-lubrication, and low friction properties of the top ceramic layer, it has a low coefficient of friction (less than 0.4) and a thermal conductivity of less than 1.8 W / (mK) at 1000-1300℃, which can significantly improve the high temperature resistance of the sealing coating. At the same time, an atmospheric laminar flow plasma spray gun is used to prepare the ceramic coating, which can prepare a ceramic coating with a high density through-crack structure. This structure can significantly improve the thermal cycle life of the sealing coating. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 This diagram illustrates a process flow chart for preparing a high-temperature resistant, self-lubricating, and low-friction sealing coating material according to an embodiment of the present invention.

[0040] Figure 2 A schematic diagram of the structure of the high-temperature resistant, self-lubricating, low-friction sealing coating material provided in an embodiment of the present invention is shown. Detailed Implementation

[0041] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0042] Specific experimental steps or conditions are not specified in the embodiments; they can be performed according to the conventional experimental steps or conditions described in the prior art. Reagents and other instruments used, unless otherwise specified, are all commercially available conventional reagent products. Furthermore, the accompanying drawings are merely illustrative diagrams of the embodiments of the present invention and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore, repeated descriptions of them will be omitted. Some block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically independent entities.

[0043] Currently, the temperature of combustion gases is approaching 2000K, significantly higher than the melting point of high-temperature alloys (approximately 1300℃). Therefore, high-temperature alloys can no longer fully meet the application requirements. To adapt to harsh high-temperature working environments, surface modification of high-temperature alloys has become necessary. Thermally insulating and wear-resistant self-sealing coatings are a type of functional coating that is resistant to high temperatures and wear, meeting the demands for both. Currently, the ceramic materials commonly used in sealing coatings include yttrium-stabilized zirconia (YSZ), gadolinium-doped zirconia (GZO), lanthanum zirconate (LZO), and lanthanum cerate (LCO), among other ultra-high temperature rare earth ceramic materials. However, these coating materials primarily function as thermal insulation and do not possess a low coefficient of friction; in fact, their coefficient of friction is relatively high and does not change significantly at high temperatures. They lack the comprehensive characteristics of self-lubrication, low friction coefficient, and high thermal insulation.

[0044] Based on this, the present invention aims to design a dual-layer gradient composite functional coating so that the prepared dual-layer ceramic coating, under the stimulation and induction of external factors, meets the multifunctional application requirements of high temperature resistance, self-lubrication, and low friction. Specific implementation methods are as follows:

[0045] In a first aspect, the present invention provides a method for preparing a high-temperature resistant, self-lubricating, low-friction sealing coating material. Figure 1 A schematic diagram of the preparation method of the high-temperature resistant, self-lubricating, low-friction sealing coating material provided in the embodiments of the present invention is shown, as follows: Figure 1 As shown, the preparation method includes the following preparation steps:

[0046] S1. NiCoCrAlY alloy powder is sprayed onto the surface of the alloy substrate using plasma spraying, supersonic flame spraying, laser cladding equipment or arc cladding equipment to form a Ni-based bonding layer.

[0047] S2. 8YSZ powder is prepared on the surface of the Ni-based adhesive layer by atmospheric laminar plasma spraying or electron beam physical vapor deposition technology to form a first ceramic coating.

[0048] S3. Further, a first combined powder of LZO, LCO and GZO in a mass ratio of 1:1:1, or a second combined powder of the first combined powder, MoS2 and CaF2 in a mass ratio of 10:3:7, is prepared on the surface of the first ceramic coating to form a second ceramic coating by atmospheric laminar plasma spraying or electron beam physical vapor deposition.

[0049] In specific implementation, the present invention provides a method for preparing a high-temperature resistant, self-lubricating, low-friction sealing coating material, which includes the following preparation steps:

[0050] Step 1: Mix the raw materials in a mass ratio of 1:1:1 to obtain an LZO-LCO-GZO co-doped zirconium oxide system, or

[0051] After mixing the raw materials in a mass ratio of 1:1:1 to obtain the LZO-LCO-GZO co-doped zirconium oxide system, MoS2 and CaF2 are further added to form a second co-doped zirconium oxide system with a mass ratio of LZO-LCO-GZO, MoS2 and CaF2 of 10:3:7. The system is then uniformly mixed by mechanical powder mixing.

[0052] The second step is to degrease and sandblast the high-temperature alloy to obtain an alloy matrix with a certain roughness. The alloy matrix can be high-temperature alloy K456 or Incoloy M956.

[0053] Step 3: Prepare a NiCoCrAlYNi-based bonding layer on a high-temperature alloy substrate using plasma spraying, supersonic flame spraying, laser cladding, or arc cladding equipment. The thickness of the bonding layer is 1-150μm.

[0054] Step 4: On the surface of the adhesive layer prepared in step 3, a ceramic layer is prepared by atmospheric laminar flow plasma spraying. The material composition of this ceramic layer is 8YSZ. By controlling the spraying parameters, an 8YSZ ceramic layer with a thickness of approximately 200μm is prepared on the adhesive layer.

[0055] Step 5: Based on the 8YSZ ceramic coating obtained in Step 4, the outermost ceramic coating is prepared by atmospheric laminar flow plasma spraying. The coating type is LZO-LCO-GZO co-doped zirconia system, or LZO-LCO-GZO co-doped zirconia system + MoS2 + CaF2 co-doped zirconia system, and the coating thickness is approximately 100μm.

[0056] Figure 2 A schematic diagram of the structure of the high-temperature resistant, self-lubricating, low-friction sealing coating material provided in an embodiment of the present invention is shown, as follows: Figure 2 As shown, the high-temperature resistant, self-lubricating, low-friction sealing coating material includes: a first ceramic coating 103 and a second ceramic coating 104 sequentially located on the surface of an alloy substrate having an adhesive layer.

[0057] The high-temperature resistant, self-lubricating, and low-friction sealing coating material prepared by this invention has a double-layer ceramic composite structure. The outermost ceramic layer possesses high-temperature resistance, self-lubrication, and low-friction sealing properties, enabling the coating to withstand higher operating temperatures during service while maintaining excellent sealing performance. In this high-temperature resistant, self-lubricating, and low-friction sealing coating material, both the first and second ceramic coatings have a high-density, penetrating vertical crack structure with a crack density of 1-4 cracks per millimeter. The presence of these penetrating vertical cracks significantly mitigates stress after thermal cycling and service, allowing the high-temperature resistant, low-friction double-layer ceramic protective coating material to adapt to current operating temperatures exceeding 1000℃.

[0058] Furthermore, the sealing coating material containing MoS2 and CaF2 provided by this invention can exhibit a low coefficient of friction (less than 0.4) and a thermal conductivity of less than 1.8 W / (mK) at 1000-1300℃, meeting the requirements for high-temperature and low-friction applications.

[0059] To enable those skilled in the art to better understand this application, the following embodiments are provided to illustrate in detail a high-temperature resistant, self-lubricating, low-friction sealing coating material and its preparation method.

[0060] Example 1: Titanium nitride coating sprayed onto the surface of high-temperature alloy K456

[0061] Nickel-based superalloy K465 alloy has high resistance to creep and fatigue and high temperature resistance.

[0062] 1) Prepare the matrix material and fix it in place using a clamping device. Mix LZO, LCO, and GZO powders evenly in a mass ratio of 1:1:1.

[0063] 2) Prepare a base material of 8×200×200mm and fix it to the base temperature control unit using a fixing clamping device.

[0064] 3) After surface sandblasting, a NiCoCrAlY coating is first applied using a supersonic flame to obtain a 150μm thick adhesive layer.

[0065] 4) Use 8YSZ powder with a particle size of 37-69μm and a powder feeding rate of 3-4g / min.

[0066] 5) Turn on the plasma control device and plasma generation device.

[0067] 6) Adjust the working gas to nitrogen and argon with a volume ratio of 7:3 using a long jet control device, with a working current of 120A and an output power of 17-18kW.

[0068] 7) Select a spraying distance of 200mm, a scanning speed of 0.4m / s, and an interval of 3mm.

[0069] 8) Turn on the powder feeding device to feed out the powder.

[0070] 9) By controlling the robotic arm, a coating with a thickness of more than 200μm can be obtained by spraying 30 times in a cycle.

[0071] 10) Replace the 8YSZ ceramic powder in the powder feeder with LZO, LCO, or GZO powder with a particle size of 40-80 μm, and repeat steps (5)-(8).

[0072] 11) By controlling the robotic arm, a coating with a thickness of more than 100μm can be obtained by spraying 20 times in a cycle.

[0073] 12) Turn off the powder feeder, then turn off the plasma generator generating unit, and finally turn off the plasma generator circulating water device.

[0074] 13) Wait for the substrate temperature control unit to lower the sample temperature to room temperature, then remove the sample to obtain the composite ceramic coating.

[0075] Example 2: Coating the surface of high-temperature alloy K456 with titanium nitride.

[0076] Nickel-based superalloy K465 alloy has high resistance to creep and fatigue and high temperature resistance.

[0077] 1) Prepare the matrix material and fix it in place using a clamping device. Mix LZO, LCO, and GZO powders evenly in a mass ratio of 1:1:1. Then mix the evenly mixed LZO, LCO, and GZO powders with MoS2 and CaF2 powders in a mass ratio of 10:3:7.

[0078] 2) Prepare the matrix material It is fixed to the substrate temperature control unit by a fixing clamping device.

[0079] 3) After surface sandblasting, a NiCoCrAlY coating is first applied using a supersonic flame to obtain a 150μm thick adhesive layer.

[0080] 4) Use 7YSZ powder with a particle size of 37-69μm and a powder feeding rate of 3-4g / min.

[0081] 5) Turn on the plasma control device and plasma generation device.

[0082] 6) The working gas is adjusted to nitrogen and argon with a volume ratio of 7:3 using a long jet control device. The working current is 120A and the output power is 17-18kW.

[0083] 7) Select a spraying distance of 200mm, a scanning speed of 0.4m / s, and an interval of 3mm.

[0084] 8) Turn on the powder feeding device to feed out the powder.

[0085] 9) By controlling the robotic arm, a coating with a thickness of more than 200μm can be obtained by spraying 30 times in a cycle.

[0086] 10) Replace the 8YSZ ceramic powder in the powder feeder with LZO, LCO, GZO, MoS2, CaF2 powder with a particle size of 40-80μm, and repeat steps (5)-(8).

[0087] 11) By controlling the robotic arm, a coating with a thickness of more than 100μm can be obtained by spraying 20 times in a cycle.

[0088] 12) Turn off the powder feeder, then turn off the plasma generator generating unit, and finally turn off the plasma generator circulating water device.

[0089] 13) Wait for the substrate temperature control unit to lower the sample temperature to room temperature, then remove the sample to obtain the composite ceramic coating.

[0090] Example 3: Titanium nitride coating sprayed onto the surface of Incoloy M956

[0091] M956 alloy has high creep strength and excellent resistance to oxidation and corrosion at high temperatures. It is widely used as a hot-end component in advanced aero-engines with operating temperatures of 1000-1200℃ and as a thermal protection component in industrial furnaces with temperatures exceeding 1300℃.

[0092] 1) Prepare the matrix material and fix it in place using a clamping device. Mix LZO, LCO, and GZO powders evenly in a mass ratio of 1:1:1. Then mix the evenly mixed LZO, LCO, and GZO powders with MoS2 and CaF2 powders in a mass ratio of 10:3:7.

[0093] 2) Prepare the matrix material It is fixed to the substrate temperature control unit by a fixing clamping device.

[0094] 3) After surface sandblasting, a NiCoCrAlY coating is first applied using a supersonic flame to obtain a 150μm thick adhesive layer.

[0095] 4) Use 8YSZ powder with a particle size of 37-69μm and a powder feeding rate of 3-4g / min.

[0096] 5) Turn on the plasma control device and plasma generation device.

[0097] 6) The working gas is adjusted to nitrogen and argon with a volume ratio of 7:3 using a long jet control device. The working current is 120A and the output power is 17-18kW.

[0098] 7) Select a spraying distance of 200mm, a scanning speed of 0.4m / s, and an interval of 3mm.

[0099] 8) Turn on the powder feeding device to feed out the powder.

[0100] 9) By controlling the robotic arm, a coating with a thickness of more than 200μm can be obtained by spraying 30 times in a cycle.

[0101] 10) Replace the 8YSZ ceramic powder in the powder feeder with LZO, LCO, GZO, MoS2, CaF2 powder with a particle size of 40-80μm, and repeat steps (5)-(8).

[0102] 11) By controlling the robotic arm, a coating with a thickness of more than 100μm can be obtained by spraying 20 times in a cycle.

[0103] 12) Turn off the powder feeder, then turn off the plasma generator generating unit, and finally turn off the plasma generator circulating water device.

[0104] 13) Wait for the substrate temperature control unit to lower the sample temperature to room temperature, then remove the sample to obtain the composite ceramic coating.

[0105] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this disclosure. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0106] For the sake of simplicity, the method embodiments are described as a series of actions. However, those skilled in the art should understand that the present invention is not limited to the described order of actions, as some steps can be performed in other orders or simultaneously according to the present invention. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and components involved are not necessarily essential to the present invention.

[0107] The above provides a detailed description of a high-temperature resistant, self-lubricating, low-friction sealing coating material and its preparation method provided by the present invention. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for preparing a high-temperature resistant, self-lubricating, low-friction sealing coating material, characterized in that, The preparation method includes the following preparation steps: S1. NiCoCrAlY alloy powder is sprayed onto the surface of the alloy substrate using plasma spraying, supersonic flame spraying, laser cladding equipment or arc cladding equipment to form a Ni-based bonding layer. S2. 8YSZ powder is prepared on the surface of the Ni-based adhesive layer by atmospheric laminar plasma spraying or electron beam physical vapor deposition technology to form a first ceramic coating. S3. Further, a first co-doped zirconium oxide system consisting of LZO, LCO and GZO in a mass ratio of 1:1:1 is prepared on the surface of the first ceramic coating by atmospheric laminar plasma spraying or electron beam physical vapor deposition technology to form a second ceramic coating. Alternatively, a first co-doped zirconium oxide system is formed by LZO, LCO and GZO in a mass ratio of 1:1:1, and a second co-doped zirconium oxide system is formed by the first co-doped zirconium oxide system, MoS2 and CaF2 in a mass ratio of 10:3:7, and is prepared on the surface of the first ceramic coating to form a second ceramic coating. In step S2, the particle size of the 8YSZ powder is 37-69 µm. The powder feeding rate of the 8YSZ powder is 3~4 g / min; The thickness of the first ceramic coating is 200-300 μm; The microstructure of the first ceramic coating has a vertical crack structure with a density of 2-4 cracks per millimeter. In step S3, the thickness of the second ceramic coating is 100-150 μm; The microstructure of the second ceramic coating has a vertical crack structure with a density of 2-4 cracks per millimeter.

2. The method for preparing the high-temperature resistant, self-lubricating, low-friction sealing coating material according to claim 1, characterized in that, In step S1, the thickness of the Ni-based adhesive layer is 1-150 μm.

3. The method for preparing the high-temperature resistant, self-lubricating, low-friction sealing coating material according to claim 1, characterized in that, In step S3, the particle size of the first co-doped zirconium oxide system, MoS2 and CaF2 is 40-80 μm.

4. The method for preparing the high-temperature resistant, self-lubricating, low-friction sealing coating material according to claim 1, characterized in that, The operating parameters of the atmospheric laminar plasma spraying technology are as follows: The volume ratio of nitrogen to argon is 7:3; The operating current is 120-160A; Output power is 15-30 kW; The spraying distance is 200-300 mm; The spraying speed is 0.4-0.8 m / s; The spraying interval is 3-8 mm.

5. The method for preparing the high-temperature resistant, self-lubricating, low-friction sealing coating material according to claim 1, characterized in that, The operating parameters of the atmospheric laminar plasma spraying technology are as follows: The volume ratio of nitrogen to argon is 7:3; The operating current is 160A; Output power is 25-26 kW; The spraying distance is 250 mm; The spraying speed is 0.4 m / s; The spraying interval is 4 mm.

6. The method for preparing the high-temperature resistant, self-lubricating, low-friction sealing coating material according to claim 1, characterized in that, The alloy matrix includes: high-temperature alloy K465 or Incoloy M956.

7. The method for preparing the high-temperature resistant, self-lubricating, low-friction sealing coating material according to claim 1, characterized in that, The surface of the alloy substrate is the surface of the alloy substrate after degreasing and sandblasting treatment.

8. A high-temperature resistant, self-lubricating, low-friction sealing coating material obtained by the preparation method according to any one of claims 1-6.

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