High-temperature-resistant abradable seal coating structure and preparation process thereof

Abstract

The application discloses a high-temperature-resistant abradable seal coating structure and a preparation process thereof, and the process comprises the following steps: 1, pretreatment of a base body; 2, preparation of an alloy bonding layer on the base body by plasma spraying or high-velocity oxygen fuel spraying; 3, preparation of a polyester honeycomb structure by fused deposition modeling (FDM), and then preheating the base body to fix the base body on the base body; 4, preparation of an interface flame-retardant layer by plasma spraying; 5, preparation of an abradable surface layer by plasma spraying; and 6, high-temperature treatment to obtain the abradable seal coating structure with the honeycomb structure. The polyester honeycomb is introduced into the seal coating by the fused deposition modeling (FDM), and the honeycomb structure pores are constructed by heat treatment, so that the strain tolerance of the seal coating is improved, the abradability is improved, the heat insulation and erosion resistance are ensured, the performance and service life of the abradable seal coating are remarkably improved, and the abradable seal coating is suitable for the sealing field between a blade tip and a casing of an aero-engine.

Description

Technical Field

[0001] This invention belongs to the field of gas turbine technology, specifically relating to a high-temperature wear-resistant sealing coating structure and its preparation process. Background Technology

[0002] With the development of the aviation industry, the vortex temperature of aero engines is constantly increasing in order to meet the performance requirements of high thrust, high thrust-to-weight ratio, high efficiency, and high reliability. Titanium alloys, due to their high specific strength, high corrosion resistance, and heat resistance, are widely used in the manufacture of engine blades and other high-strength parts such as casings and stators. However, during engine operation, due to differences in thermal expansion, machining errors, and assembly tolerances, the collision and friction between the casing and engine blades causes the titanium alloy temperature to rise and potentially burn, posing significant economic and safety hazards. Currently, the application of abrasive coatings on the surfaces of casings and stators allows the coating to actively wear down when rubbing against rotor components. This ensures minimal clearance between the rotor and stator, protecting engine blades from wear and achieving air passage sealing. This is of great significance for reducing fuel consumption, improving efficiency, and enhancing operational safety.

[0003] With the increasing performance requirements of aero-engines and the increasingly harsh operating environment, single-function wearable sealing coatings that resist titanium fire are no longer sufficient to meet service requirements. Currently, the airflow temperature after combustion chamber heating can reach over 800K to 1000K, making it impossible for wearable surfaces to operate for extended periods at such high temperatures. Therefore, a thermal barrier coating (TG) needs to be prepared between the wearable coating and the metal bonding layer as part of the sealing coating. However, after a certain service time, thermal barrier coatings can experience problems such as coating breakage or peeling due to the formation of a thermally grown oxide layer (TGO) between the ceramic layer and the bonding layer under high-temperature conditions. Therefore, long-term stable service is fundamental for the thermal barrier coating to effectively perform its thermal insulation function. Thus, improving the strain tolerance of the thermal barrier coating to enhance the thermal shock resistance and lifespan of the composite coating is of great significance.

[0004] In the preparation of abrasive sealing coatings, the abrasive surface layer is mainly composed of Ni-diatomaceous earth, NiCr-graphite, and NiCrAl-bentonite to ensure labyrinth sealing of the compressor surface, thereby reducing leakage of high-pressure airflow inside the engine and completing the air passage sealing. Simultaneously, under the wear service conditions of the sealing coating, it needs to possess high abrasiveness and high erosion resistance. However, higher hardness corresponds to lower abrasiveness and stronger erosion resistance. Addressing this contradictory relationship, how to achieve a coating that combines high abrasiveness with good erosion resistance is a key issue in developing high-performance sealing coatings. Summary of the Invention

[0005] The technical problem to be solved by this invention is to provide a preparation process for a high-temperature wear-resistant sealing coating structure, addressing the shortcomings of the prior art. This method introduces polyester honeycomb material into the sealing coating through fused deposition modeling (FDM) and constructs the honeycomb structure pores through heat treatment. This gives the sealing coating vertical strain tolerance, reducing its hardness while the small honeycomb structure allows gas flow within the coating, ensuring its erosion resistance. This significantly improves the performance and service life of the wear-resistant sealing coating, solving the problem of limited coating strain tolerance and the contradiction between wear resistance and erosion resistance in the prior art.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a preparation process for a high-temperature resistant and wear-resistant sealing coating structure, characterized in that the process includes the following steps:

[0007] Step 1: Pre-treat the substrate by sandblasting and degassing;

[0008] Step 2: Prepare an alloy bonding layer on the substrate pretreated in Step 1 by plasma spraying or supersonic flame spraying to obtain a substrate with an alloy bonding layer.

[0009] Step 3: Prepare a polyester honeycomb structure by fused deposition modeling (FDM), then preheat the substrate with alloy bonding layer obtained in Step 2, and fix the polyester honeycomb structure on the alloy bonding layer in parallel hexagonal grids to obtain a substrate with a polyester honeycomb structure.

[0010] Step 4: Prepare an interfacial flame-retardant layer on the surface of the substrate with a polyester honeycomb structure obtained in Step 3 by plasma spraying;

[0011] Step 5: Prepare a wearable surface layer by plasma spraying the flame-retardant interfacial layer prepared in step 3 to obtain the structural part to be treated;

[0012] Step 6: The structural component to be processed obtained in Step 5 is subjected to high-temperature treatment, which causes the polyester honeycomb structure to melt and evaporate, forming a wear-resistant sealing coating structure with a honeycomb structure on the substrate.

[0013] Typically, the alloy bonding layer described in step two of this invention is made by spraying MCrAlY-based powder, where M is Co or Ni, and the thickness is 100μm to 150μm. The MCrAlY-based powder is prepared by spray granulation and is a spherical powder with a particle size of -45μm to +15μm.

[0014] Typically, the polyester honeycomb structure described in step three of this invention is made of polyester powder. The side length of the regular hexagonal grid in the polyester honeycomb structure is 1mm to 20mm, the thickness is 0.6mm to 0.8mm, the grid line width constituting the regular hexagonal grid is 100μm to 120μm, and the polyester powder is composed of 70% to 80% polymethyl methacrylate (PMMA) and 20% to 30% starch acetate by mass fraction.

[0015] Typically, the raw materials for preparing the interfacial flame-retardant layer in step four of this invention are selected from lanthanum zirconate (LZO) powder, yttrium-stabilized zirconium oxide (YSZ) powder, lanthanum cerate (LCO) powder, lanthanum hexaaluminate (LA) powder, and alumina powder.

[0016] Typically, the raw materials for preparing the wearable surface layer in step five of this invention are Ni-diatomaceous earth powder, NiCr-graphite powder, or NiCrAl-bentonite powder.

[0017] The above-mentioned process for preparing a high-temperature resistant and wear-resistant sealing coating structure is characterized in that the printing process parameters for preparing the polyester honeycomb structure by fused deposition modeling (FDM) in step three are: extrusion temperature 450K~480K, plateau temperature 320K~330K, printing speed 20mm / s~50mm / s, minimum nozzle diameter 0.1mm, and layer thickness 0.1mm~0.2mm.

[0018] The above-mentioned preparation process of a high-temperature wear-resistant sealing coating structure is characterized in that the preheating temperature in step three is 400K~500K and the holding time is 10min.

[0019] The above-mentioned preparation process of a high-temperature resistant, wear-resistant sealing coating structure is characterized in that the process parameters for plasma spraying in steps two, four, and five are as follows: spraying voltage 130V~135V, spraying current 400A~420A, spraying air pressure 0.7MPa~0.8MPa, spraying distance 100mm~120mm, the spraying air source is compressed air and Ar gas, and the main compressed air flow rate is 25.4L·min. -1 The auxiliary gas Ar flow rate is 220 L·min -1 .

[0020] The above-mentioned process for preparing a high-temperature resistant, wear-resistant sealing coating structure is characterized in that, in step six, the high-temperature treatment involves placing the structural component to be treated in a muffle furnace and holding it at 600°C for 2 to 3 hours. By controlling the temperature and time of the high-temperature treatment, the polyester honeycomb structure in the treated structural component is ensured to melt and evaporate completely, leaving a sealing coating with an intact honeycomb structure.

[0021] Meanwhile, the present invention also discloses a high-temperature wear-resistant sealing coating structure prepared by the above-mentioned process, characterized in that the total thickness of the high-temperature wear-resistant sealing coating structure is 0.8mm to 1.1mm, wherein the thickness of the alloy bonding layer is 100μm to 200μm, the thickness of the interface flame retardant layer is 300μm to 400μm, and the thickness of the wear-resistant surface layer is 400μm to 500μm.

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] 1. This invention prepares a polyester honeycomb structure by fused deposition modeling (FDM) and introduces it into a sealing coating structure. Combined with a heat treatment process, the polyester honeycomb structure is volatilized, thereby creating pores in the honeycomb structure within the sealing coating. On the one hand, the vertical microporous structure improves the strain tolerance of the sealing coating. On the other hand, the presence of pores reduces the overall hardness of the sealing coating surface, ensuring the wearability of the sealing coating while ensuring that the erosion resistance of the sealing coating is not significantly reduced. This results in a wearable sealing coating structure that is resistant to high temperatures, has high wearability, and good erosion resistance, significantly improving the service life of the wearable sealing coating structure.

[0024] 2. The regular honeycomb structure in the sealing coating structure of the present invention ensures the flow of gas inside the sealing coating structure. When applied to a compressor, it improves the sealing of the gas passage between the compressor casing and the rotor, ensures the gap and heat transfer rate of high strength-to-weight ratio parts, and when applied to seals, it enables them to withstand high-temperature oxidation, increases the radial expansion of rotor blades, reduces cold-forming gaps, thereby improving the efficiency of the gas turbine and possessing great application potential.

[0025] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the process for preparing polyester honeycomb structures by fused deposition modeling (FDM) according to the present invention.

[0027] Figure 2 This is a schematic diagram of the cross-sectional structure of the structural component to be processed according to the present invention. Detailed Implementation

[0028] like Figure 1 As shown, the process of preparing polyester honeycomb structures by fused deposition modeling (FDM) is as follows: first, 3D printing is used to deposit and form hexagonal grid polyester sheets, and the hexagonal grid polyester sheets are deposited layer by layer to form hexagonal grid polyester blocks. Then, several hexagonal grid polyester blocks are deposited and connected to form a polyester honeycomb structure.

[0029] Example 1

[0030] This embodiment includes the following steps:

[0031] Step 1: Pre-treat the substrate by sandblasting and degassing;

[0032] Step 2: An alloy bonding layer is prepared on the substrate pretreated in Step 1 by plasma spraying or supersonic flame spraying, resulting in a substrate with an alloy bonding layer. The alloy bonding layer is made by spraying CoCrAlY powder with a thickness of 100μm. The CoCrAlY powder is prepared by spray granulation and is a spherical powder with a particle size of -45μm to +15μm.

[0033] Step 3: Prepare a polyester honeycomb structure by fused deposition modeling (FDM). Then, preheat the substrate with the alloy bonding layer obtained in Step 2, and fix the polyester honeycomb structure onto the alloy bonding layer in parallel hexagonal grids to obtain a substrate with a polyester honeycomb structure. The polyester honeycomb structure is made of polyester powder. The side length of the hexagonal grid in the polyester honeycomb structure is 1 mm, the thickness is 0.6 mm, and the grid line width is 110 μm. The polyester powder consists of 70% polymethyl methacrylate (PMMA) and 30% starch acetate by mass fraction.

[0034] The printing process parameters for preparing polyester honeycomb structures by fused deposition modeling (FDM) are: extrusion temperature 450K, plateau temperature 330K, printing speed 30mm / s, minimum nozzle diameter 0.1mm, and layer thickness 0.1mm.

[0035] The preheating temperature is 400K, and the holding time is 10min;

[0036] Step 4: Using yttrium oxide stabilized zirconia (YSZ) powder as raw material, an interfacial flame-retardant layer with a thickness of 300 μm is prepared on the surface of the substrate with a polyester honeycomb structure obtained in Step 3 by plasma spraying.

[0037] Step 5: Using Ni-diatomaceous earth powder as raw material, a wearable surface layer with a thickness of 400 μm is prepared on the surface of the interfacial flame-retardant layer prepared in Step 3 by plasma spraying, thus obtaining the structural component to be treated, such as... Figure 2 As shown;

[0038] Step 6: Place the structural component to be processed obtained in Step 5 into a muffle furnace and hold it at 600℃ for 3 hours for high-temperature treatment, so that the polyester honeycomb structure melts and evaporates, forming a wearable sealing coating structure with a honeycomb structure on the substrate, with a total thickness of 0.8mm.

[0039] The process parameters for the thermal spray coating are as follows: spraying voltage 130V, spraying current 420A, spraying air pressure 0.7MPa, spraying distance 120mm, and the spraying air source is compressed air and Ar gas, with a main compressed air flow rate of 25.4L·min. -1 The auxiliary gas Ar flow rate is 220 L·min -1 .

[0040] Testing revealed that the abrasive sealing coating structure prepared in this embodiment has a honeycomb structure, and the porosity of the abrasive sealing coating structure is 18.1%, with a bonding strength of 39 MPa.

[0041] In step four of this invention, the raw materials for preparing the interfacial flame-retardant layer can also be one or more of the following: lanthanum zirconate (LZO) powder, yttrium-stabilized zirconia (YSZ) powder, lanthanum cerate (LCO) powder, lanthanum hexaaluminate powder, and alumina powder, in addition to yttrium oxide-stabilized zirconia (YSZ) powder.

[0042] Example 2

[0043] This embodiment includes the following steps:

[0044] Step 1: Pre-treat the substrate by sandblasting and degassing;

[0045] Step 2: An alloy bonding layer is prepared on the substrate pretreated in Step 1 by plasma spraying or supersonic flame spraying, resulting in a substrate with an alloy bonding layer. The alloy bonding layer is made by spraying NiCrAlY powder with a thickness of 110 μm. The NiCrAlY powder is prepared by spray granulation and is a spherical powder with a particle size of -45 μm to +15 μm.

[0046] Step 3: Prepare a polyester honeycomb structure by fused deposition modeling (FDM). Then, preheat the substrate with the alloy bonding layer obtained in Step 2, and fix the polyester honeycomb structure onto the alloy bonding layer in parallel hexagonal grids to obtain a substrate with a polyester honeycomb structure. The polyester honeycomb structure is made of polyester powder. The side length of the hexagonal grid in the polyester honeycomb structure is 10 mm, the thickness is 0.7 mm, and the grid line width is 120 μm. The polyester powder consists of 80% polymethyl methacrylate (PMMA) and 20% starch acetate by mass fraction.

[0047] The printing process parameters for preparing polyester honeycomb structures by fused deposition modeling (FDM) are: extrusion temperature 480K, plateau temperature 320K, printing speed 20mm / s, minimum nozzle diameter 0.1mm, and layer thickness 0.2mm.

[0048] The preheating temperature is 500K, and the holding time is 10 minutes;

[0049] Step 4: Using 80% lanthanum cerate (LCO) powder and 20% lanthanum hexaaluminate powder as raw materials by mass fraction, an interfacial flame-retardant layer with a thickness of 350 μm is prepared on the surface of the substrate with polyester honeycomb structure obtained in Step 3 by plasma spraying.

[0050] Step 5: Using NiCr-graphite powder as raw material, a wearable surface layer with a thickness of 500 μm is prepared on the surface of the interfacial flame-retardant layer prepared in Step 3 by plasma spraying, resulting in the structural component to be treated, such as... Figure 2 As shown;

[0051] Step 6: Place the structural component to be processed obtained in Step 5 into a muffle furnace and hold it at 600℃ for 2 hours for high-temperature treatment, so that the polyester honeycomb structure melts and volatilizes, forming a wearable sealing coating structure with a honeycomb structure on the substrate, with a total thickness of 0.9mm.

[0052] The process parameters for the thermal spray coating are as follows: spraying voltage 135V, spraying current 400A, spraying air pressure 0.8MPa, spraying distance 100mm, and the spraying air source is compressed air and Ar gas, with a main compressed air flow rate of 25.4L·min. -1 The auxiliary gas Ar flow rate is 220 L·min -1 .

[0053] Testing revealed that the abrasive sealing coating structure prepared in this embodiment has a honeycomb structure, and the porosity of the abrasive sealing coating structure is 24.8%, with a bonding strength of 50 MPa.

[0054] Example 3

[0055] This embodiment includes the following steps:

[0056] Step 1: Pre-treat the substrate by sandblasting and degassing;

[0057] Step 2: An alloy bonding layer is prepared on the substrate pretreated in Step 1 by plasma spraying or supersonic flame spraying, resulting in a substrate with an alloy bonding layer. The alloy bonding layer is made by spraying CoCrAlY powder with a thickness of 200μm. The CoCrAlY powder is prepared by spray granulation and is a spherical powder with a particle size of -45μm to +15μm.

[0058] Step 3: Prepare a polyester honeycomb structure by fused deposition modeling (FDM). Then, preheat the substrate with the alloy bonding layer obtained in Step 2, and fix the polyester honeycomb structure onto the alloy bonding layer in parallel hexagonal grids to obtain a substrate with a polyester honeycomb structure. The polyester honeycomb structure is made of polyester powder. The side length of the hexagonal grid in the polyester honeycomb structure is 20 mm, the thickness is 0.8 mm, and the grid line width is 100 μm. The polyester powder consists of 75% polymethyl methacrylate (PMMA) and 25% starch acetate by mass fraction.

[0059] The printing process parameters for preparing polyester honeycomb structures by fused deposition modeling (FDM) are: extrusion temperature 460K, plateau temperature 325K, printing speed 50mm / s, minimum nozzle diameter 0.1mm, and layer thickness 0.15mm.

[0060] The preheating temperature is 460K, and the holding time is 10min;

[0061] Step 4: Using lanthanum zirconate (LZO) powder as raw material, an interfacial flame-retardant layer with a thickness of 400 μm is prepared on the surface of the substrate with a polyester honeycomb structure obtained in Step 3 by plasma spraying.

[0062] Step 5: Using NiCrAl-bentonite powder as raw material, a wearable surface layer with a thickness of 500 μm is prepared on the surface of the interfacial flame-retardant layer prepared in Step 3 by plasma spraying, thus obtaining the structural component to be treated, such as... Figure 2 As shown;

[0063] Step 6: Place the structural component to be processed obtained in Step 5 into a muffle furnace and hold it at 600℃ for 3 hours for high-temperature treatment, so that the polyester honeycomb structure melts and evaporates, forming a wearable sealing coating structure with a honeycomb structure on the substrate, with a total thickness of 1.1mm.

[0064] The process parameters for the thermal spray coating are as follows: spraying voltage 130V, spraying current 400A, spraying air pressure 0.7MPa, spraying distance 120mm, and the spraying air source is compressed air and Ar gas, with a main compressed air flow rate of 25.4L·min. -1 The auxiliary gas Ar flow rate is 220 L·min -1 .

[0065] Testing revealed that the abrasive sealing coating structure prepared in this embodiment has a honeycomb structure, and the porosity of the abrasive sealing coating structure is 24.7%, with a bonding strength of 58 MPa.

[0066] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Any simple modifications, alterations, and equivalent changes made to the above embodiments based on the inventive essence shall still fall within the protection scope of the present invention.

Claims

1. A process for preparing a high temperature resistant abradable seal coat structure, characterized in that, The process includes the following steps: Step 1: Pre-treat the substrate by sandblasting and degassing; Step 2: Prepare an alloy bonding layer on the substrate pretreated in Step 1 by plasma spraying or supersonic flame spraying to obtain a substrate with an alloy bonding layer. Step 3: Prepare a polyester honeycomb structure by fused deposition modeling (FDM), then preheat the substrate with alloy bonding layer obtained in Step 2, and fix the polyester honeycomb structure on the alloy bonding layer in parallel hexagonal grids to obtain a substrate with a polyester honeycomb structure. Step 4: Prepare an interfacial flame-retardant layer on the surface of the substrate with a polyester honeycomb structure obtained in Step 3 by plasma spraying; Step 5: Prepare a wearable surface layer by plasma spraying the flame-retardant interfacial layer prepared in step 3 to obtain the structural part to be treated; Step 6: The structural component to be processed obtained in Step 5 is subjected to high-temperature treatment, which causes the polyester honeycomb structure to melt and evaporate, forming a wear-resistant sealing coating structure with a honeycomb structure on the substrate.

2. The process for preparing a high-temperature resistant abradable seal structure according to claim 1, characterized in that, The printing process parameters for preparing polyester honeycomb structures by fused deposition modeling (FDM) in step three are as follows: extrusion temperature 450K~480K, plateau temperature 320K~330K, printing speed 20mm / s~50mm / s, minimum nozzle diameter 0.1mm, and layer thickness 0.1mm~0.2mm.

3. The preparation process of a high-temperature wear-resistant sealing coating structure according to claim 1, characterized in that, The preheating temperature in step three is 400K to 500K, and the holding time is 10 minutes.

4. The preparation process of a high-temperature wear-resistant sealing coating structure according to claim 1, characterized in that, The process parameters of the plasma spraying in the second step, the fourth step and the fifth step are as follows: spraying voltage 130V-135V, spraying current 400A-420A, spraying air pressure 0.7MPa-0.8MPa, spraying distance 100mm-120mm, and spraying gas source is compressed air and Ar gas, wherein the flow of the main gas (compressed air) is 25.4L·min -1 , and the flow of the auxiliary gas (Ar gas) is 220L·min -1 .

5. The preparation process of a high-temperature wear-resistant sealing coating structure according to claim 1, characterized in that, The high-temperature treatment described in step six involves placing the structural component to be treated into a muffle furnace and holding it at 600°C for 2 to 3 hours.

6. A high-temperature wear-resistant sealing coating structure prepared by the process described in any one of claims 1 to 5, characterized in that, The total thickness of the high-temperature resistant wear-resistant sealing coating structure is 0.8mm to 1.1mm, wherein the thickness of the alloy bonding layer is 100μm to 200μm, the thickness of the interface flame retardant layer is 300μm to 400μm, and the thickness of the wear-resistant surface layer is 400μm to 500μm.

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