A high-toughness high-temperature-resistant multi-component composite structure coating, a preparation method and applications thereof

Abstract

The present application relates to the technical field of cermet coating, and particularly relates to a high-strength and high-toughness high-temperature-resistant multi-component composite structure coating, a preparation method and application thereof, the multi-component composite structure coating sequentially comprises a multi-layer coating and an Al2O3 / ZrO2-r-BN / ZrO2-Al2O3 / Cr2O3 surface modification layer, and the multi-layer coating sequentially comprises a CoNiCrAlY adhesive layer, a CoNiCrAlY-Al2O3 fiber transition layer and a CoNiCrAlY-Al2O3 fiber / ZrB2 functional layer. The present application utilizes the reinforcing and toughening effect of Al2O3 fiber and the dispersion strengthening effect of ZrB2, and solves the problems of easy delamination and low bonding strength of the traditional coating under high-temperature cyclic stress by constructing a multi-layer structure coating with gradient hardness and toughness. A stable and dense multi-component composite pure ceramic modification layer is formed through pre-oxidation-nitriding treatment, so that the coating finally has excellent fracture toughness and high-temperature performance.

Description

Technical Field

[0001] This invention relates to the field of metal-ceramic coating technology, specifically to a high-strength, high-toughness, high-temperature resistant multi-component composite coating, its preparation method, and its application. Background Technology

[0002] Key components in aerospace, power generation, and metallurgy industries operate under extreme conditions such as high temperature, heavy load, mechanical wear, and thermal cycling for extended periods, making them susceptible to various forms of failure. Common failure modes include oxidation and corrosion failure caused by the reaction of material surfaces with oxygen or corrosive media at high temperatures; wear failure caused by mechanical friction and particle erosion; and thermal fatigue cracking caused by stress concentration due to repeated thermal expansion and contraction. Furthermore, coating peeling due to interfacial stress caused by mismatched coefficients of thermal expansion is also a common failure mode. These failures, stemming from complex multi-field coupling effects, seriously threaten component lifespan and system safety. Therefore, improving the protective performance of surface coatings on critical components is crucial for ensuring reliable equipment operation. CoNiCrAlY coatings have attracted considerable attention due to their excellent oxidation resistance, but their insufficient wear resistance limits their application under extreme conditions. To improve this, the addition of ceramic reinforcing phases, such as ZrB2, is commonly employed. These ceramics not only possess high melting points, high hardness, and good chemical stability but also significantly enhance the overall wear resistance of the coating. However, the significant difference in thermal expansion coefficients between the ceramic phase and the metal matrix often leads to internal stress in the coating during thermal cycling, resulting in interfacial delamination and coating failure. The introduction of Al2O3 fibers has proven to be an effective toughening method; its unique fiber structure can alleviate stress concentration through crack deflection and bridging mechanisms, thereby improving the coating's toughness. This multi-component composite coating design concept, through the synergistic effect of metal and ceramic, significantly improves wear resistance and bonding strength while maintaining the substrate's oxidation resistance.

[0003] It is worth noting that composite coatings still struggle to meet protection requirements under certain special service environments. For example, exogenous reactive oxides such as Fe3O4 and Mn3O4 can directly contact and chemically react with elements like Cr and Al in the coating at high temperatures, generating complex nodules that are difficult to remove. These nodules not only accelerate the oxidation and deterioration of the coating but also form uneven protrusions on the surface of critical components, severely affecting their surface quality. This migration and consumption of Cr and Al elements caused by chemical reactions leads to continuous depletion of the coating composition and a decline in its protective performance. Therefore, how to construct an effective diffusion barrier layer through surface pretreatment technology to block direct contact between reactive elements and external oxides has become a key issue in improving the service performance of protective coatings.

[0004] In view of the above-mentioned defects, the inventors of this invention have finally obtained this invention after a long period of research and practice. Summary of the Invention

[0005] The purpose of this invention is to solve the problem that it is difficult to prepare metal-ceramic composite coatings with high bonding strength, high toughness and wear resistance on the surface of high-temperature components using single-layer or double-layer structural designs. At the same time, it overcomes the defect that the active elements in the alloy phase of the composite coating react directly with external oxides such as Fe3O4 and Mn3O4, leading to nodule formation and premature failure. The invention provides a high-strength, high-toughness, high-temperature resistant multi-component composite structure coating, its preparation method and its application.

[0006] To achieve the above objectives, the present invention discloses a high-strength, high-toughness, and high-temperature resistant multi-component composite structure coating. The multi-component composite structure coating includes a multilayer coating and an Al2O3 / ZrO2-r-BN / ZrO2-Al2O3 / Cr2O3 surface modification layer arranged sequentially from the substrate. The multilayer coating includes a CoNiCrAlY adhesive layer, a CoNiCrAlY-Al2O3 fiber transition layer, and a CoNiCrAlY-Al2O3 fiber / ZrB2 functional layer arranged sequentially from the substrate.

[0007] The thickness of the CoNiCrAlY adhesive layer is 40-60 μm, the thickness of the CoNiCrAlY-Al2O3 fiber transition layer is 50-80 μm, the thickness of the CoNiCrAlY-Al2O3 fiber / ZrB2 functional layer is 110-150 μm, and the thickness of the Al2O3 / ZrO2-r-BN / ZrO2-Al2O3 / Cr2O3 surface modification layer is 1.4-1.5 μm.

[0008] The Al2O3 fiber content in the CoNiCrAlY-Al2O3 fiber transition layer is 3wt.%~7wt.%, and the average fiber diameter is 0.5μm.

[0009] The content of Al2O3 fiber in the CoNiCrAlY-Al2O3 fiber / ZrB2 functional layer is 3wt.%~5wt.%, with an average fiber diameter of 0.5μm, and the content of ZrB2 is 15wt.%~25wt.%, with a particle size of 1-3μm.

[0010] This invention also discloses a method for preparing the above-mentioned high-strength, high-toughness, and high-temperature resistant multi-component composite structure coating, comprising the following steps:

[0011] S1. Grind and polish the multi-layer coating surface, place it in an annealing furnace and seal it. Introduce high-purity nitrogen into the furnace chamber for 60-120 minutes to expel the air inside the furnace chamber.

[0012] S2, after heating the furnace cavity, a mixture of nitrogen and oxygen is introduced and kept at the temperature for pre-oxidation treatment;

[0013] S3, after introducing high-purity nitrogen again, heat to 1180~1200℃, hold for 480min, and perform pre-nitriding treatment;

[0014] S4, the temperature is lowered to 400~470℃ at 5℃ / min. After reaching the set temperature, a mixture of nitrogen and oxygen gas is introduced again and kept at the temperature for 180min. Finally, it is cooled to room temperature at a rate of 5℃ / min for stabilization treatment, and finally the Al2O3 / ZrO2-r-BN / ZrO2-Al2O3 / Cr2O3 surface modified layer is obtained.

[0015] In step S1, the multilayer coating is applied from the substrate outwards using supersonic flame spraying technology, consisting of a CoNiCrAlY adhesive layer, a CoNiCrAlY-Al2O3 fiber transition layer, and a CoNiCrAlY-Al2O3 fiber / ZrB2 functional layer.

[0016] In step S2, the heating rate is 8℃ / min, the temperature is raised to 760~800℃, and the volume ratio of nitrogen to oxygen in the mixed gas is 4:1.

[0017] In step S3, the heating rate is 5℃ / min.

[0018] In step S4, the volume ratio of nitrogen to oxygen in the mixed gas is 9:1.

[0019] The present invention also discloses the application of the above-mentioned high-strength, high-toughness, high-temperature resistant multi-component composite structure coating in the protection of high-temperature components.

[0020] Compared with existing technologies, the advantages of this invention are as follows:

[0021] 1. The CoNiCrAlY adhesive layer, prepared by supersonic flame spraying, leverages its excellent metallic plasticity and high-temperature oxidation resistance to form a metallurgical bond with the heat-resistant steel substrate, significantly improving the interfacial bonding strength. In the CoNiCrAlY-Al2O3 fiber transition layer, the metallic phase has the same composition as the adhesive layer, enabling a gradient transition of the coefficient of thermal expansion. The uniformly distributed Al2O3 fibers can enhance the fracture toughness of the coating through crack deflection and fiber pull-out mechanisms, and also act as a hard reinforcing phase to improve the load-bearing capacity of the transition layer, thereby reducing the tendency of the coating to delamination under cyclic stress.

[0022] 2. The ZrB2 particles in the CoNiCrAlY-Al2O3 fiber / ZrB2 functional layer significantly improve the coating's hardness and wear resistance through a dispersion strengthening effect, while also providing a key component source for the formation of the surface modification layer. This results in an Al2O3 / ZrO2-r-BN / ZrO2-Al2O3 / Cr2O3 surface modification layer extending outwards from the coating after pre-oxidation-nitriding treatment. The outermost Al2O3 / Cr2O3 layer effectively blocks direct contact between Fe3O4 and Mn3O4 and Cr and Al elements in the alloy phase, preventing nodulation. The middle r-BN / ZrO2 layer, with its continuous and dense microstructure, significantly inhibits the high-temperature penetration of N and O elements, thus preventing nitriding and oxidation within the coating. The inner Al2O3 / ZrO2 hard ceramic layer provides excellent mechanical support. This multi-component synergistic mechanism enables the multi-component composite coating of this invention to exhibit excellent toughness, wear resistance, and anti-nodulation properties. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the pre-oxidation-nitriding surface modification treatment;

[0024] Figure 2 SEM image of the coating before pre-oxidation-nitriding treatment;

[0025] Figure 3 This is a SEM image of the surface modified layer after the coating pre-oxidation-nitriding treatment. Detailed Implementation

[0026] The above-mentioned and other technical features and advantages of the present invention will be described in more detail below with reference to the accompanying drawings.

[0027] Example 1

[0028] A method for preparing a multilayer coating (before pre-oxidation-nitriding surface modification) in a high-strength, high-toughness, high-temperature resistant multi-component composite structure coating includes: firstly, preparing CoNiCrAlY-Al2O3 fiber composite powder and CoNiCrAlY-Al2O3 fiber / ZrB2 composite powder by mechanical alloying; secondly, applying a CoNiCrAlY adhesive layer to a heat-resistant steel substrate by supersonic flame spraying; thirdly, applying a CoNiCrAlY-Al2O3 fiber transition layer to the surface of the adhesive layer by supersonic flame spraying; and fourthly, applying a CoNiCrAlY-Al2O3 fiber / ZrB2 functional layer to the surface of the transition layer by supersonic flame spraying.

[0029] The mechanical alloying preparation process of the above CoNiCrAlY-Al2O3 fiber composite powder includes the following steps:

[0030] (1) First, weigh the CoNiCrAlY powder and Al2O3 fiber used in the mechanical alloying method of CoNiCrAlY-Al2O3 fiber composite powder. The mass ratio is CoNiCrAlY powder:Al2O3 fiber = 0.97:0.03. Calculate the total mass of these materials.

[0031] (2) Add the weighed CoNiCrAlY powder and Al2O3 fiber to the ball mill jar, add mixed grinding balls to the ball mill jar, the size and mass ratio of the mixed grinding balls is 15mm:10mm:6mm=1:4:2, the total mass ratio of the mixed grinding balls to the total mass of the elemental powder is 10:1; then seal the ball mill jar, and perform vacuuming and argon filling treatment inside the jar, the vacuum degree should be below 10Pa, the argon filling gas is high purity argon gas, the pressure is 0.2-0.3MPa, and the filling time is 15min.

[0032] (3) Place the grinding jar in an all-around planetary ball mill, set the ball milling speed to 220 rpm, and make a cycle of 50 min forward rotation, 10 min stop, 50 min reverse rotation, and 10 min stop. The ball milling time is 20 h.

[0033] (4) After a total ball milling time of 35 h, CoNiCrAlY-Al2O3 fiber composite powder with a particle size range of 15-53 μm was screened out.

[0034] The mechanical alloying preparation process of the above CoNiCrAlY-Al2O3 fiber / ZrB2 composite powder includes the following steps:

[0035] (1) First, weigh the CoNiCrAlY powder, Al2O3 fiber and ZrB2 powder used in the mechanical alloying method of CoNiCrAlY-Al2O3 fiber / ZrB2 composite powder. The mass ratio is CoNiCrAlY powder:Al2O3 fiber:ZrB2 powder = 0.8:0.03:0.17. Calculate the total mass of these materials.

[0036] (2) Add the weighed CoNiCrAlY powder and Al2O3 fiber to the ball mill jar, add the mixed grinding balls to the ball mill jar, the size and mass ratio of the mixed grinding balls is 15mm:10mm:6mm=1:4:2, the total mass ratio of the mixed grinding balls to the total mass of the powder material is 10:1; then seal the ball mill jar, and perform vacuuming and argon filling treatment inside the jar, the vacuum degree should be below 10Pa, the argon filling gas is high purity argon gas, the pressure is 0.2-0.3MPa, and the filling time is 15min.

[0037] (3) Place the grinding jar in an all-around planetary ball mill, set the ball milling speed to 220 rpm, and make a cycle of 50 min forward rotation, 10 min stop, 50 min reverse rotation, and 10 min stop. The ball milling time is 20 h.

[0038] (4) After ball milling for 20 hours, open the ball milling jar, add the weighed ZrB2 powder, and perform the sealing, vacuuming and argon filling treatments in step (2) on the ball milling jar. Then continue ball milling for 15 hours according to the parameters in step (3).

[0039] (5) After a total ball milling time of 35 h, CoNiCrAlY-Al2O3 fiber / ZrB2 composite powder with a particle size range of 15-53 μm was screened out.

[0040] The above-mentioned process for preparing the CoNiCrAlY adhesive layer, CoNiCrAlY-Al2O3 fiber transition layer, and CoNiCrAlY-Al2O3 fiber / ZrB2 functional layer by supersonic flame spraying includes the following steps:

[0041] (1) Dry the pure CoNiCrAlY, CoNiCrAlY-Al2O3 fiber, and CoNiCrAlY-Al2O3 fiber / ZrB2 powder to remove excess moisture. The drying temperature is 60℃ and the time is 30min.

[0042] (2) The surface of the heat-resistant steel substrate is roughened by sandblasting. 24-mesh brown corundum sand is used and the sandblasting carrier gas pressure is 0.2-0.4MPa. The substrate after sandblasting is cleaned with anhydrous ethanol or acetone.

[0043] (3) Kerosene flow rate 28L / h, oxygen flow rate 800L / min, spraying distance 380mm, powder feeding rate 32g / min. Two spraying passes are applied to obtain a CoNiCrAlY bonding layer with a thickness of 40-60μm; three spraying passes are applied to obtain a CoNiCrAlY-Al2O3 fiber transition layer with a thickness of 50-80μm; five spraying passes are applied to obtain a CoNiCrAlY-Al2O3 fiber / ZrB2 functional layer with a thickness of 110-150μm.

[0044] Example 2

[0045] A method for preparing a CoNiCrAlY-Al2O3 transition layer includes first preparing CoNiCrAlY-Al2O3 composite powder by mechanical alloying, and then preparing the CoNiCrAlY-Al2O3 transition layer by supersonic flame spraying.

[0046] The mechanical alloying preparation process of the above CoNiCrAlY-Al2O3 composite powder includes the following steps:

[0047] (1) First, weigh out the CoNiCrAlY and Al2O3 powders used in the mechanical alloying method of CoNiCrAlY-Al2O3 composite powder. The mass ratio of CoNiCrAlY powder:Al2O3 powder = 0.97:0.03 and the average particle size of Al2O3 powder is 0.5μm.

[0048] (2) Add the weighed CoNiCrAlY powder and Al2O3 powder to the ball mill jar. The other process steps are the same as steps 2 to 4 of the mechanical alloying preparation process of CoNiCrAlY-Al2O3 fiber composite powder in Example 1.

[0049] The process steps in the preparation of the supersonic flame spraying CoNiCrAlY-Al2O3 transition layer are the same as those in Example 1.

[0050] The microhardness and fracture toughness of the CoNiCrAlY adhesive layer, CoNiCrAlY-Al2O3 fiber transition layer, CoNiCrAlY-Al2O3 transition layer and CoNiCrAlY-Al2O3 fiber / ZrB2 functional layer prepared in Examples 1 and 2 are shown in Table 1.

[0051] Table 1 Microhardness and fracture toughness of the coating

[0052]

[0053] As shown in Table 1, the CoNiCrAlY-Al2O3 fiber / ZrB2 functional layer exhibits the highest microhardness and fracture toughness, which are 745.61±11.71 HV, respectively. 0.3 and 5.46±0.48 This can significantly improve the wear resistance and anti-stripping ability of the composite structure coating. Although the microhardness of the CoNiCrAlY-Al2O3 fiber transition layer is not significantly improved compared to the CoNiCrAlY-Al2O3 transition layer with ordinary Al2O3 ceramic particles, the bridging mechanism of Al2O3 fibers can alleviate stress concentration, thus significantly improving the fracture toughness of the transition layer. At the same time, the microhardness and fracture toughness of the transition layer are between those of the CoNiCrAlY adhesive layer, thereby achieving a gradient distribution of the mechanical properties of the multi-layer coating, which helps to improve the overall performance of the multi-component composite structure coating.

[0054] Example 3

[0055] The difference between this embodiment and Embodiment 1 is that the CoNiCrAlY-Al2O3 fiber / ZrB2 functional layer is prepared directly on the heat-resistant steel substrate, while the other process steps are the same as in Embodiment 1.

[0056] Example 4

[0057] The difference between this embodiment and Embodiment 1 is that the CoNiCrAlY adhesive layer and the CoNiCrAlY-Al2O3 fiber / ZrB2 functional layer are prepared directly on the heat-resistant steel substrate, while the other process steps are the same as in Embodiment 1.

[0058] Example 5

[0059] The difference between this embodiment and Embodiment 1 is that the CoNiCrAlY-Al2O3 transition layer and the CoNiCrAlY-Al2O3 fiber / ZrB2 functional layer are prepared directly on the heat-resistant steel substrate, while the other process steps are the same as in Embodiment 1.

[0060] Example 6

[0061] The difference between this embodiment and Embodiment 1 is that the CoNiCrAlY-Al2O3 fiber transition layer and the CoNiCrAlY-Al2O3 fiber / ZrB2 functional layer are prepared directly on the heat-resistant substrate, while the other process steps are the same as in Embodiment 1.

[0062] The bonding strength of the single-layer, double-layer, and multi-layer coatings prepared in Examples 1, 3-6 was measured using a universal tensile testing machine, and the results are shown in Table 2. The bonding strength of the single-layer functional layer was only 45.36 ± 8.36 MPa. The bonding strength was improved by preparing a double-layer coating. The double-layer structure consisting of an adhesive layer and a functional layer had a bonding strength of 64.78 ± 4.16 MPa, indicating that the adhesive layer significantly improved the bonding strength of the coating. In contrast, the addition of Al2O3 ceramic particles to the CoNiCrAlY-Al2O3 transition layer resulted in a decrease in the bonding strength of the double-layer coating, reaching only 47.44 ± 5.43 MPa. However, the CoNiCrAlY-Al2O3 fiber transition layer using Al2O3 fibers as the reinforcing phase did not lead to a decrease in bonding strength. Finally, the bonding strength of the multi-layer combination using an adhesive layer, a CoNiCrAlY-Al2O3 fiber transition layer, and a functional layer was further improved, reaching 68.31 ± 3.18 MPa.

[0063] Table 2 Bond strength of different types of coatings

[0064]

[0065] Example 7

[0066] A method for preparing a surface-modified Al2O3 / ZrO2-r-BN / ZrO2-Al2O3 / Cr2O3 surface layer by multilayer coating pre-oxidation-nitridation includes the following steps:

[0067] (1) Polish the surface of the multi-layer coating, and thoroughly clean the polished surface with anhydrous ethanol or acetone.

[0068] (2) Place the polished multilayer coating into the annealing furnace and introduce high-purity nitrogen into the furnace cavity for 60 minutes to remove the air inside the furnace cavity.

[0069] (3) Heat the temperature to 760℃ at 8℃ / min. After reaching the set temperature, introduce a mixture of nitrogen and oxygen (volume ratio of N2:O2=4:1) into the furnace cavity and keep it at the temperature for 60min for pre-oxidation treatment.

[0070] (4) High-purity nitrogen gas is introduced again and the temperature is raised to 1180℃ at 5℃ / min and then kept at the temperature for 480min for pre-nitriding treatment.

[0071] (5) After cooling to 400℃ at 5℃ / min, a mixture of nitrogen and oxygen (volume ratio of N2:O2=9:1) is introduced into the furnace cavity and kept at the temperature for 180min for stabilization treatment.

[0072] (6) After the holding time is reached, cool to room temperature at a rate of 5℃ / min, during which a mixture of nitrogen and oxygen (volume ratio of N2:O2=9:1) is continuously introduced at a flow rate of 2L / min. Finally, an Al2O3 / ZrO2-r-BN / ZrO2-Al2O3 / Cr2O3 surface modification layer is obtained from the coating outwards. The process is as follows: Figure 1 As shown.

[0073] Example 8

[0074] The difference between this embodiment and embodiment 7 is that the heat preservation time of the pre-oxidation treatment in step (3) of preparing the Al2O3 / ZrO2-r-BN / ZrO2-Al2O3 / Cr2O3 surface modification layer is 30 min, and the other process steps are the same as in embodiment 7.

[0075] Example 9

[0076] The difference between this embodiment and embodiment 7 is that the heat preservation time of the pre-oxidation treatment in step (3) of preparing the Al2O3 / ZrO2-r-BN / ZrO2-Al2O3 / Cr2O3 surface modification layer is 90 min, and the other process steps are the same as in embodiment 7.

[0077] Example 10

[0078] The difference between this embodiment and embodiment 7 is that the heat preservation time of the pre-nitriding treatment in step (4) of preparing the Al2O3 / ZrO2-r-BN / ZrO2-Al2O3 / Cr2O3 surface modification layer is 420 min, and the other process steps are the same as in embodiment 7.

[0079] Example 11

[0080] The difference between this embodiment and embodiment 7 is that the heat preservation time of the pre-nitriding treatment in step (4) of preparing the Al2O3 / ZrO2-r-BN / ZrO2-Al2O3 / Cr2O3 surface modification layer is 540 min, and the other process steps are the same as in embodiment 7.

[0081] Example 12

[0082] The difference between this embodiment and embodiment 7 is that the heat preservation time of the pre-oxidation treatment in step (3) of preparing Al2O3 / ZrO2-r-BN / ZrO2-Al2O3 / Cr2O3 surface modification layer is 60 min, and the heat preservation time of the pre-nitridation treatment in step (4) is 0 min. Other process steps are the same as in embodiment 7, that is, only the pre-oxidation treatment is performed.

[0083] Example 13

[0084] The difference between this embodiment and embodiment 7 is that the holding time for the pre-oxidation treatment in step (3) of preparing the Al2O3 / ZrO2-r-BN / ZrO2-Al2O3 / Cr2O3 surface modification layer is 0 min, and the holding time for the pre-nitridation treatment in step (4) is 480 min. Other process steps are the same as in embodiment 7, that is, only the pre-nitridation treatment is performed.

[0085] The thickness and fracture toughness of the surface modified layers prepared in Examples 7-13 after pre-oxidation and pre-nitriding treatments at different times were measured, and the results are shown in Table 3. The thickness of the surface modified layer increased with the extension of the pre-oxidation and pre-nitriding treatment time. When the pre-oxidation treatment time was extended from 30 min to 90 min, the thickness of the surface modified layer increased from 0.97±0.33 μm to 1.83±0.26 μm. When the pre-nitriding treatment time was extended from 420 min to 540 min, the thickness increased from 1.28±0.34 μm to 1.77±0.18 μm. However, the fracture toughness of the modified layer first increased and then decreased, reaching its highest value of 6.03±0.13 μm after 60 min of pre-oxidation and 480 min of pre-nitriding treatment. In addition, the pre-oxidation-nitriding treatment had a synergistic toughening effect, resulting in a fracture toughness higher than that of pre-oxidation alone (4.67±0.34). ) and pre-nitrided (5.01±0.19) The results were all higher after processing.

[0086] Table 3. Surface modification layer thickness and fracture toughness after pre-oxidation-nitriding treatment

[0087]

[0088] The coatings prepared in Examples 1, 7, 12, and 13 before and after surface pretreatment were subjected to performance tests: the high-temperature wear performance of the coatings was tested using a high-temperature friction and wear tester; the anti-nodding performance of the coatings was tested using a dynamic nodulation test method; and the cross-sections of the coatings before and after pre-oxidation-nitriding were observed using SEM. Figure 2 and Figure 3 As shown. By Figure 2 It can be seen that the multilayer coating is dense and non-porous, with clear interfaces between layers and no obvious defects or inclusions at the interfaces. From the substrate outward, it includes a CoNiCrAlY bonding layer with a thickness of about 50 μm, a CoNiCrAlY-Al2O3 fiber transition layer with a thickness of about 80 μm, and a CoNiCrAlY-Al2O3 fiber / ZrB2 functional layer with a thickness of about 150 μm. Figure 3 The pre-oxidized and nitrided Al2O3 / ZrO2-r-BN / ZrO2-Al2O3 / Cr2O3 surface modified layer shown has a thickness of 1.45 μm and exhibits good interfacial bonding with the CoNiCrAlY-Al2O3 fiber / ZrB2 functional layer.

[0089] The results of friction and wear tests on the coatings before and after surface treatment at 1000℃ are shown in Table 4. The coefficient of friction and wear rate of the coating before pre-oxidation-nitriding were 0.56±0.12 and 4.95×10, respectively. -14 The coefficient of friction and wear rate of the coating decreased after pre-oxidation treatment. In contrast, the coefficient of friction and wear rate of the coating decreased more significantly after pre-nitriding treatment, by 0.44±0.07 and 2.72×10⁻⁶, respectively. -14 After pre-oxidation-nitriding treatment, a mixed surface modification layer composed of Al2O3 / ZrO2-r-BN / ZrO2-Al2O3 / Cr2O3 appeared on the surface. These hard ceramics synergistically played a role in lubrication and wear resistance, further reducing the coefficient of friction and wear rate of the pre-oxidation-nitriding coating to 0.38±0.04 and 2.13×10, respectively. -14 .

[0090] Table 4. Friction coefficient and wear rate of coatings before and after pre-oxidation-nitriding

[0091]

[0092] Table 5 shows the weight gain and nodule thickness of the coatings before and after surface treatment at different nodule formation test times. The weight gain before and after pre-oxidation-nitriding increased with increasing test time. Specifically, the weight gain of the coating before pre-oxidation-nitriding after 1 hour of testing was 1.34 ± 0.13 mg / cm³. 2 The weight gain of the pre-oxidized-nitrided coating after 1 hour was only 0.51 ± 0.06 mg / cm³. 2 After 20 hours of testing, the weight gain of the coatings before and after pre-oxidation-nitriding was 5.76 ± 0.64 mg / cm³. 2 and 2.02±0.25mg / cm 2 Meanwhile, the thickness increases caused by nodule formation were 3.01 μm and 1.13 μm, respectively. Comparing the weight gain and nodule thickness of the samples after pre-oxidation and pre-nitriding treatments, it can be seen that the synergistic effect of pre-oxidation-nitriding treatment has a more significant effect on improving the anti-nodulation performance of the coating.

[0093] Table 5. Weight gain and nodule thickness of coatings before and after pre-oxidation-nitriding nodule test

[0094]

[0095] Based on the comprehensive analysis of microhardness, fracture toughness, bonding strength, friction coefficient, wear rate, and nodulation test results of the coatings before and after pre-oxidation-nitriding treatment, the following conclusions can be drawn: The above steps can produce a multi-component composite coating with good bonding strength, higher hardness, and fracture toughness. After pre-oxidation-nitriding treatment, a multi-layered Al2O3 / ZrO2-r-BN / ZrO2-Al2O3 / Cr2O3 surface modification layer is also formed on the coating surface. Compared to pre-oxidation or pre-nitriding treatment alone, this synergistic pre-oxidation-nitriding treatment method significantly improves the fracture toughness, high-temperature wear resistance, and anti-nodulation properties of the multi-component composite coating.

[0096] The above description is merely a preferred embodiment of the present invention and is illustrative rather than restrictive. Those skilled in the art will understand that many changes, modifications, and even equivalents can be made within the spirit and scope defined by the claims of the present invention, all of which will fall within the protection scope of the present invention.

Claims

1. A high-strength, high-toughness, high-temperature resistant multi-component composite coating, characterized in that, The multi-component composite structure coating includes a multi-layer coating and an Al2O3 / ZrO2-r-BN / ZrO2-Al2O3 / Cr2O3 surface modification layer arranged sequentially from the substrate. The Al2O3 / ZrO2-r-BN / ZrO2-Al2O3 / Cr2O3 surface modification layer includes an inner Al2O3 / ZrO2 layer, a middle r-BN / ZrO2 layer, and an outermost Al2O3 / Cr2O3 layer. The multi-layer coating includes a CoNiCrAlY adhesive layer, a CoNiCrAlY-Al2O3 fiber transition layer, and a CoNiCrAlY-Al2O3 fiber / ZrB2 functional layer arranged sequentially from the substrate. The preparation method of the high-strength, tough, and high-temperature resistant multi-component composite structure coating includes the following steps: S1. Grind and polish the multi-layer coating surface, place it in an annealing furnace and seal it. Introduce high-purity nitrogen into the furnace chamber for 60-120 minutes to expel the air inside the furnace chamber. S2, after heating the furnace cavity, a mixture of nitrogen and oxygen is introduced and kept at the temperature for pre-oxidation treatment; S3, after introducing high-purity nitrogen again, heat to 1180~1200℃, hold for 480min, and perform pre-nitriding treatment; S4, the temperature is lowered to 400~470℃ at 5℃ / min. After reaching the set temperature, a mixture of nitrogen and oxygen gas is introduced again and kept at the temperature for 180min. Finally, it is cooled to room temperature at a rate of 5℃ / min for stabilization treatment, and finally the Al2O3 / ZrO2-r-BN / ZrO2-Al2O3 / Cr2O3 surface modified layer is obtained.

2. The high-strength, high-toughness, high-temperature resistant multi-component composite coating as described in claim 1, characterized in that, The thickness of the CoNiCrAlY adhesive layer is 40-60 μm, the thickness of the CoNiCrAlY-Al2O3 fiber transition layer is 50-80 μm, the thickness of the CoNiCrAlY-Al2O3 fiber / ZrB2 functional layer is 110-150 μm, and the thickness of the Al2O3 / ZrO2-r-BN / ZrO2-Al2O3 / Cr2O3 surface modification layer is 1.4-1.5 μm.

3. The high-strength, high-toughness, high-temperature resistant multi-component composite coating as described in claim 1, characterized in that, The Al2O3 fiber content in the CoNiCrAlY-Al2O3 fiber transition layer is 3wt.%~7wt.%, and the average fiber diameter is 0.5μm.

4. The high-strength, high-toughness, high-temperature resistant multi-component composite coating as described in claim 1, characterized in that, The content of Al2O3 fiber in the CoNiCrAlY-Al2O3 fiber / ZrB2 functional layer is 3wt.%~5wt.%, with an average fiber diameter of 0.5μm, and the content of ZrB2 is 15wt.%~25wt.%, with a particle size of 1-3μm.

5. The high-strength, high-toughness, high-temperature resistant multi-component composite coating as described in claim 1, characterized in that, In step S1, the multilayer coating is applied from the substrate outwards using supersonic flame spraying technology, consisting of a CoNiCrAlY adhesive layer, a CoNiCrAlY-Al2O3 fiber transition layer, and a CoNiCrAlY-Al2O3 fiber / ZrB2 functional layer.

6. The high-strength, high-toughness, high-temperature resistant multi-component composite coating as described in claim 1, characterized in that, In step S2, the heating rate is 8℃ / min, the temperature is raised to 760~800℃, and the volume ratio of nitrogen to oxygen in the mixed gas is 4:

1.

7. The high-strength, high-toughness, high-temperature resistant multi-component composite coating as described in claim 1, characterized in that, In step S3, the heating rate is 5℃ / min.

8. The high-strength, high-toughness, high-temperature resistant multi-component composite coating as described in claim 1, characterized in that, In step S4, the volume ratio of nitrogen to oxygen in the mixed gas is 9:

1.

9. The application of a high-strength, high-toughness, high-temperature resistant multi-component composite structure coating as described in any one of claims 1 to 8 in the protection of high-temperature components.

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