Thermal barrier coating with double-bonding-layer structure and preparation method of thermal barrier coating

Abstract

The invention discloses a thermal barrier coating with a double-bonding-layer structure and a preparation method thereof, and belongs to the field of thermal barrier coatings. According to the thermal barrier coating, nickel-based high-temperature alloy serves as a substrate, the thermal barrier coating sequentially comprises an MCrAlY lower bonding layer, a Cr2AlC upper bonding layer and an 8YSZ ceramic layer, the MCrAlY lower bonding layer and the Cr2AlC upper bonding layer are prepared through the high velocity oxy-fuel spraying technology, and the 8YSZ ceramic layer is prepared through the atmosphere plasma spraying technology. According to the thermal barrier coating system, through the synergistic effect of the oxidation resistance of the Cr2AlC upper bonding layer and the mutual diffusion inhibition characteristic of the MCrAlY lower bonding layer, the comprehensive performance of the thermal barrier coating is optimized, meanwhile, the anti-stripping capacity of the thermal barrier coating system is remarkably improved, and the thermal barrier coating system is suitable for various high-temperature alloy substrates, is not limited by alloy component differences, can further adapt to workpieces in complex geometrical shapes and is suitable for industrial production. The method can be used for protecting hot-end components such as aero-engine turbine blades and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of thermal barrier coatings, and in particular relates to a thermal barrier coating with a double bonding layer structure and a preparation method thereof. Background Art

[0002] As an important symbol of a country's scientific and technological strength and industrial level, the performance of aircraft engines directly determines the overall performance of the aircraft. Increasing the temperature before the turbine is a key way to enhance engine thrust and thermal efficiency, but the resulting high temperature environment (1800-2050K) exceeds the temperature limit of high-temperature alloy blades. To this end, thermal barrier coating (TBC) technology has emerged. It is usually composed of a ceramic layer and a bonding layer. The former is responsible for heat insulation and resistance to gas erosion, and the latter is used to enhance the compatibility of the ceramic layer with the metal substrate and form an α- The main dense thermally grown oxide (TGO) provides anti-oxidation protection for the substrate.

[0003] Traditional TBC generally uses MCrAlY (M=Ni, Co, etc.) as the bonding layer, but it faces two major bottlenecks: the non-protective TGO formed at high temperature generates large growth stress, leading to premature failure; the thermal expansion coefficient (16× ) is too high, and TGO (9.3× ) and ceramic layer (11× ) mismatch is serious. In recent years, MAX phase materials (M is a transition metal element, A is a main group element, and X is C and / or N) that have both metal and ceramic properties have attracted much attention. Among them, Outstanding performance: excellent oxidation resistance, can still form dense α- Protective film, oxidation kinetics follows the cubic law; thermal expansion coefficient (13.3× ) between the ceramic layer and the substrate (>15× ) and is more closely matched with TGO. In 2020, Gonzalez et al. found that YSZ / The / Inconel 738 system can achieve 745 thermal cycles at 1400°C, verifying its feasibility as a bonding layer.

[0004] However, despite It exhibits excellent oxidation resistance and thermal expansion coefficient matching, and the element interdiffusion between it and the nickel-based alloy substrate is more significant than that of the traditional MCrAlY bonding layer. The weak Cr-Al bonds in the bonded layer lead to the release of a large amount of Al at high temperatures, which in turn forms a brittle interdiffusion zone at the bond layer / substrate interface. Under the action of thermal-mechanical coupling, this brittle zone is prone to crack initiation and leads to interfacial delamination and cracking.

[0005] Therefore, a new bonding layer system is urgently needed to take into account both antioxidant and interdiffusion inhibition capabilities, thereby improving the overall performance of TBC. Summary of the Invention

[0006] In order to overcome the shortcomings of the above-mentioned prior art, the present invention proposes a thermal barrier coating with a double bonding layer structure. The thermal barrier coating adopts a multi-layer structure design, with a nickel-based high-temperature alloy as the substrate, and NiCoCrAlYHf and The outermost layer is 8YSZ ceramic layer. Among them, NiCoCrAlYHf can effectively inhibit The elements between the substrate and the This multi-layer structure design achieves an optimal balance between antioxidant performance and mutual diffusion inhibition through synergistic effect.

[0007] The thermal barrier coating with a double bonding layer structure of the present invention is composed of a ceramic layer and a bonding layer; the bonding layer is composed of It is composed of an upper bonding layer and a NiCoCrAlYHf lower bonding layer. The upper bonding layer is provided between the ceramic layer and the NiCoCrAlYHf lower bonding layer; the ceramic layer is 8YSZ ceramic;

[0008] In the NiCoCrAlYHf lower bonding layer, the content of Ni is 54wt%-71wt%, the content of Co is 0-20wt%, the content of Cr is 12wt%-22wt%, the content of Al is 6wt%-11wt%, the content of Y is 0.5wt%-1wt%, and the content of Hf is 0-0.5wt%.

[0009] The preparation method of the thermal barrier coating having a double bonding layer structure of the present invention is carried out according to the following steps:

[0010] Step 1: Pre-treat the substrate and spray powder separately;

[0011] The spraying powder is NiCoCrAlYHf powder, Powder and ceramic layer powder; the ceramic layer powder is 8YSZ ceramic powder;

[0012] Step 2: using supersonic flame spraying to spray NiCoCrAlYHf powder on the surface of the substrate to form a NiCoCrAlYHf lower bonding layer;

[0013] Step 3: Use supersonic flame spraying to Powder spraying is formed on the surface of NiCoCrAlYHf lower bonding layer Upper bonding layer;

[0014] Step 4: Use atmospheric plasma spraying to spray the ceramic layer powder on A ceramic layer is formed on the surface of the upper bonding layer.

[0015] The principles and beneficial effects of the present invention are:

[0016] 1. the present invention / NiCoCrAlYHf double bonding layer structure thermal barrier coating passed The excellent oxidation resistance of the upper bonding layer provides antioxidant protection, while the strong Ni-Al bond of the NiCoCrAlYHf lower bonding layer inhibits the mutual diffusion of elements. The synergistic effect of the two not only solves the technical difficulty of traditional single-layer bonding layers in taking into account both antioxidant and mutual diffusion inhibition, but also significantly improves the interface bonding strength and stress distribution state of the coating system by precisely controlling the matching of the thermal expansion coefficients of the two layers of materials, thereby significantly improving the anti-stripping performance of the coating.

[0017] 2. Compared with other spraying methods, the supersonic flame spraying used in the present invention has the advantages of high deposition efficiency, low cost, high coating bonding strength, low porosity, and low oxide content, and is very suitable for the preparation of NiCoCrAlYHf and Adhesive layer.

[0018] 3. The present invention / NiCoCrAlYHf double bonding layer structure thermal barrier coating has a wide range of applicability. It is suitable for various high-temperature alloy substrates and is not restricted by differences in alloy composition. It can also adapt to workpieces with complex geometries and can be used to protect hot end components such as aircraft engine turbine blades.

[0019] Based on the above analysis, the present invention constructs The NiCoCrAlYHf double bonding layer structure innovatively achieves the synergistic optimization of antioxidant performance improvement and mutual diffusion inhibition, providing new ideas for the development of high-temperature protective coating technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is the XRD pattern of the NiCoCrAlYHf lower bonding layer in the thermal barrier coating prepared in Example 1;

[0021] Figure 2 This is a cross-sectional SEM photograph of the NiCoCrAlYHf lower bonding layer in the thermal barrier coating prepared in Example 1;

[0022] Figure 3 In the thermal barrier coating prepared in Example 1 XRD pattern of the upper bonding layer;

[0023] Figure 4 In the thermal barrier coating prepared in Example 1 Cross-sectional SEM photograph of the upper bonding layer;

[0024] Figure 5 This is the XRD pattern of the 8YSZ ceramic layer in the thermal barrier coating prepared in Example 1;

[0025] Figure 6 This is a cross-sectional SEM photograph of the 8YSZ ceramic layer in the thermal barrier coating prepared in Example 1;

[0026] Figure 7 This is a cross-sectional SEM photograph of the thermal barrier coating prepared in Example 1 after oxidation at 1100°C for 50 hours;

[0027] Figure 8 These are cross-sectional SEM photographs of the thermal barrier coating prepared in Comparative Example 1 after oxidation at 1100°C for 50 hours: a is a cross-sectional SEM photograph of the coating area after the thermal barrier coating cracks, and b is a cross-sectional SEM photograph of the substrate area after the thermal barrier coating cracks. DETAILED DESCRIPTION

[0028] The technical solution of the present invention is not limited to the specific implementation methods listed below, but also includes any reasonable combination of the specific implementation methods.

[0029] Specific embodiment 1: The thermal barrier coating with a double bonding layer structure in this embodiment is composed of a ceramic layer and a bonding layer; the bonding layer is composed of It is composed of an upper bonding layer and a NiCoCrAlYHf lower bonding layer. The upper bonding layer is provided between the ceramic layer and the NiCoCrAlYHf lower bonding layer; the ceramic layer is 8YSZ ceramic;

[0030] In the NiCoCrAlYHf lower bonding layer, the content of Ni is 54wt%-71wt%, the content of Co is 0-20wt%, the content of Cr is 12wt%-22wt%, the content of Al is 6wt%-11wt%, the content of Y is 0.5wt%-1wt%, and the content of Hf is 0-0.5wt%.

[0031] This embodiment has the following beneficial effects:

[0032] 1. This embodiment / NiCoCrAlYHf double bonding layer structure thermal barrier coating passed The excellent oxidation resistance of the upper bonding layer provides antioxidant protection, while the strong Ni-Al bond of the NiCoCrAlYHf lower bonding layer inhibits the mutual diffusion of elements. The synergistic effect of the two not only solves the technical difficulty of traditional single-layer bonding layers in taking into account both antioxidant and mutual diffusion inhibition, but also significantly improves the interface bonding strength and stress distribution state of the coating system by precisely controlling the matching of the thermal expansion coefficients of the two layers of materials, thereby significantly improving the anti-stripping performance of the coating.

[0033] 2. Compared with other spraying methods, the supersonic flame spraying used in this embodiment has the advantages of high deposition efficiency, low cost, high coating bonding strength, low porosity, and low oxide content, and is very suitable for the preparation of NiCoCrAlYHf and Adhesive layer.

[0034] 3. This embodiment / NiCoCrAlYHf double bonding layer structure thermal barrier coating has a wide range of applicability. It is suitable for various high-temperature alloy substrates and is not restricted by differences in alloy composition. It can also adapt to workpieces with complex geometries and can be used to protect hot end components such as aircraft engine turbine blades.

[0035] Based on the above analysis, this embodiment constructs The NiCoCrAlYHf double bonding layer structure innovatively achieves the synergistic optimization of antioxidant performance improvement and mutual diffusion inhibition, providing new ideas for the development of high-temperature protective coating technology.

[0036] Specific embodiment 2: This embodiment differs from the specific embodiment 1 in that the thickness of the NiCoCrAlYHf lower bonding layer is 30-100 μm. The thickness of the upper bonding layer is 30-100 μm, and the thickness of the ceramic layer is 150-500 μm.

[0037] Specific embodiment 3: The preparation method of the thermal barrier coating with a double bonding layer structure in this embodiment is carried out according to the following steps:

[0038] Step 1: Pre-treat the substrate and spray powder separately;

[0039] The spraying powder is NiCoCrAlYHf powder, Powder and ceramic layer powder; the ceramic layer powder is 8YSZ ceramic powder;

[0040] Step 2: using supersonic flame spraying to spray NiCoCrAlYHf powder on the surface of the substrate to form a NiCoCrAlYHf lower bonding layer;

[0041] Step 3: Use supersonic flame spraying to Powder spraying is formed on the surface of NiCoCrAlYHf lower bonding layer Upper bonding layer;

[0042] Step 4: Use atmospheric plasma spraying to spray the ceramic layer powder on A ceramic layer is formed on the surface of the upper bonding layer.

[0043] 1. This embodiment / NiCoCrAlYHf double bonding layer structure thermal barrier coating passed The excellent oxidation resistance of the upper bonding layer provides antioxidant protection, while the strong Ni-Al bond of the NiCoCrAlYHf lower bonding layer inhibits the mutual diffusion of elements. The synergistic effect of the two not only solves the technical difficulty of traditional single-layer bonding layers in taking into account both antioxidant and mutual diffusion inhibition, but also significantly improves the interface bonding strength and stress distribution state of the coating system by precisely controlling the matching of the thermal expansion coefficients of the two layers of materials, thereby significantly improving the anti-stripping performance of the coating.

[0044] 2. Compared with other spraying methods, the supersonic flame spraying used in this embodiment has the advantages of high deposition efficiency, low cost, high coating bonding strength, low porosity, and low oxide content, and is very suitable for the preparation of NiCoCrAlYHf and Adhesive layer.

[0045] 3. This embodiment / NiCoCrAlYHf double bonding layer structure thermal barrier coating has a wide range of applicability. It is suitable for various high-temperature alloy substrates and is not restricted by differences in alloy composition. It can also adapt to workpieces with complex geometries and can be used to protect hot end components such as aircraft engine turbine blades.

[0046] Based on the above analysis, this embodiment constructs The NiCoCrAlYHf double bonding layer structure innovatively achieves the synergistic optimization of antioxidant performance improvement and mutual diffusion inhibition, providing new ideas for the development of high-temperature protective coating technology.

[0047] Specific embodiment 4: This embodiment differs from specific embodiment 3 in that: the substrate in step 1 is a nickel-based high-temperature alloy.

[0048] Specific embodiment 5: This embodiment differs from specific embodiment 3 in that: the median diameter of the NiCoCrAlYHf powder in step 1 is 13.57 μm; The median diameter of the powder is 25.33 μm; the median diameter of the ceramic layer powder is 63.25 μm.

[0049] Specific embodiment six: This embodiment differs from specific embodiment three in that: the pretreatment of the substrate in step one is grinding, sandblasting and cleaning to improve the bonding strength between the coating and the substrate.

[0050] Specific embodiment seven: This embodiment differs from specific embodiment six in that: the blasting medium used for sandblasting is chrome steel sand, the sandblasting pressure is 0.5-0.7 MPa, and the sandblasting distance is 180-220 mm; the cleaning uses acetone or anhydrous ethanol to ultrasonically clean the substrate; the pretreatment of the spray powder is a drying treatment to remove moisture contained in the spray powder and increase the fluidity of the powder.

[0051] Specific embodiment eight: This embodiment differs from specific embodiment three in that the process of supersonic flame spraying in step two is: the fuel flow rate is 19-23 L·h -1 , oxygen flow rate 870-880L·min -1 , spraying distance 280-320mm, powder feeding rate 70-80g·min -1 .

[0052] Specific embodiment 9: This embodiment differs from specific embodiment 3 in that the process of supersonic flame spraying in step 3 is: fuel flow rate 60-80mL·min -1 , oxygen flow rate 230-250mL·min -1 , spraying distance 140-180mm, powder feeding rate 5-6kg·h -1 .

[0053] Specific embodiment 10: The difference between this embodiment and specific embodiment 3 is that the process of atmospheric plasma spraying in step 4 is: current 500-550A, voltage 71-75V, spraying distance 80-100cm, powder feeding rate 36-44g·min -1 .

[0054] Example 1:

[0055] The preparation method of the thermal barrier coating having a double bonding layer structure of this embodiment is carried out according to the following steps:

[0056] Step 1: Pre-treat the substrate and spray powder separately;

[0057] The substrate is a nickel-based high-temperature alloy;

[0058] The spraying powder is NiCoCrAlYHf powder, Powder and ceramic layer powder; the ceramic layer powder is 8YSZ ceramic powder;

[0059] In the NiCoCrAlYHf powder, the content of Ni is 71 wt %, the content of Cr is 22 wt %, the content of Al is 6 wt %, the content of Y is 1 wt %, the content of Co is 0, and the content of Hf is 0.

[0060] The median diameter of the NiCoCrAlYHf powder is 13.57 μm; The median diameter of the powder is 25.33 μm; the median diameter of the ceramic layer powder is 63.25 μm;

[0061] The pretreatment of the substrate includes grinding, sandblasting and cleaning to improve the bonding strength between the coating and the substrate; 100#, 500#, 1000# and 3000# SiC sandpaper are used in sequence during grinding; the sandblasting medium used in the sandblasting is chrome steel sand, the sandblasting pressure is 0.6MPa, and the sandblasting distance is 200mm; the cleaning is performed by ultrasonic cleaning of the substrate with anhydrous ethanol;

[0062] The pretreatment of the spray powder is a drying process to remove the moisture contained in the spray powder and increase the fluidity of the powder; the drying process temperature is 80°C and the time is 12 hours;

[0063] Step 2: using supersonic flame spraying to spray NiCoCrAlYHf powder on the surface of the substrate to form a NiCoCrAlYHf lower bonding layer;

[0064] The process of the supersonic flame spraying is as follows: fuel flow rate 21L·h -1 , oxygen flow rate 876L·min -1 , spraying distance 300mm, powder feeding rate 75g·min -1 ;

[0065] Step 3: Use supersonic flame spraying to Powder spraying is formed on the surface of NiCoCrAlYHf lower bonding layer Upper bonding layer;

[0066] The process of the supersonic flame spraying is as follows: fuel flow rate 70mL·min -1 , oxygen flow rate 240mL·min -1 , spraying distance 180mm, powder feeding rate 5kg·h -1 ;

[0067] Step 4: Use atmospheric plasma spraying to spray the ceramic layer powder on A ceramic layer is formed on the surface of the upper bonding layer.

[0068] The atmospheric plasma spraying process is as follows: current 550A, voltage 73V, spraying distance 80cm, powder feeding rate 40g·min -1.

[0069] Example 2:

[0070] The preparation method of the thermal barrier coating having a double bonding layer structure of this embodiment is carried out according to the following steps:

[0071] Step 1: Pre-treat the substrate and spray powder separately;

[0072] The substrate is a nickel-based high-temperature alloy;

[0073] The spraying powder is NiCoCrAlYHf powder, Powder and ceramic layer powder; the ceramic layer powder is 8YSZ ceramic powder;

[0074] In the NiCoCrAlYHf powder, the content of Ni is 58.2 wt %, the content of Co is 13 wt %, the content of Cr is 20 wt %, the content of Al is 8 wt %, the content of Y is 0.8 wt %, and the content of Hf is 0.

[0075] The median diameter of the NiCoCrAlYHf powder is 13.57 μm; The median diameter of the powder is 25.33 μm; the median diameter of the ceramic layer powder is 63.25 μm;

[0076] The pretreatment of the substrate includes grinding, sandblasting and cleaning to improve the bonding strength between the coating and the substrate; 100#, 500#, 1000# and 3000# SiC sandpaper are used in sequence during grinding; the sandblasting medium used in the sandblasting is chrome steel sand, the sandblasting pressure is 0.6MPa, and the sandblasting distance is 200mm; the cleaning is performed by ultrasonic cleaning of the substrate with anhydrous ethanol;

[0077] The pretreatment of the spray powder is a drying process to remove the moisture contained in the spray powder and increase the fluidity of the powder; the drying process temperature is 80°C and the time is 12 hours;

[0078] Step 2: using supersonic flame spraying to spray NiCoCrAlYHf powder on the surface of the substrate to form a NiCoCrAlYHf lower bonding layer;

[0079] The process of the supersonic flame spraying is as follows: fuel flow rate 22L·h -1 , oxygen flow rate 873L·min -1 , spraying distance 280mm, powder feeding rate 72g·min -1 ;

[0080] Step 3: Use supersonic flame spraying to Powder spraying is formed on the surface of NiCoCrAlYHf lower bonding layer Upper bonding layer;

[0081] The process of the supersonic flame spraying is as follows: fuel flow rate 70mL·min -1 , oxygen flow rate 240mL·min -1 , spraying distance 180mm, powder feeding rate 5kg·h -1 ;

[0082] Step 4: Use atmospheric plasma spraying to spray the ceramic layer powder on A ceramic layer is formed on the surface of the upper bonding layer.

[0083] The atmospheric plasma spraying process is as follows: current 550A, voltage 73V, spraying distance 80cm, powder feeding rate 40g·min -1 .

[0084] Example 3:

[0085] The preparation method of the thermal barrier coating having a double bonding layer structure of this embodiment is carried out according to the following steps:

[0086] Step 1: Pre-treat the substrate and spray powder separately;

[0087] The substrate is a nickel-based high-temperature alloy;

[0088] The spraying powder is NiCoCrAlYHf powder, Powder and ceramic layer powder; the ceramic layer powder is 8YSZ ceramic powder;

[0089] In the NiCoCrAlYHf powder, the content of Ni is 57 wt %, the content of Co is 20 wt %, the content of Cr is 12 wt %, the content of Al is 10 wt %, the content of Y is 0.5 wt %, and the content of Hf is 0.5 wt %.

[0090] The median diameter of the NiCoCrAlYHf powder is 13.57 μm; The median diameter of the powder is 25.33 μm; the median diameter of the ceramic layer powder is 63.25 μm;

[0091] The pretreatment of the substrate includes grinding, sandblasting and cleaning to improve the bonding strength between the coating and the substrate; 100#, 500#, 1000# and 3000# SiC sandpaper are used in sequence during grinding; the sandblasting medium used in the sandblasting is chrome steel sand, the sandblasting pressure is 0.6MPa, and the sandblasting distance is 200mm; the cleaning is performed by ultrasonic cleaning of the substrate with anhydrous ethanol;

[0092] The pretreatment of the spray powder is a drying process to remove the moisture contained in the spray powder and increase the fluidity of the powder; the drying process temperature is 80°C and the time is 12 hours;

[0093] The pretreatment is drying to remove the moisture in the spray powder and increase the fluidity of the powder;

[0094] Step 2: using supersonic flame spraying to spray NiCoCrAlYHf powder on the surface of the substrate to form a NiCoCrAlYHf lower bonding layer;

[0095] The process of the supersonic flame spraying is as follows: fuel flow rate 21L·h -1 , oxygen flow rate 876L·min -1 , spraying distance 300mm, powder feeding rate 75g·min -1 ;

[0096] Step 3: Use supersonic flame spraying to Powder spraying is formed on the surface of NiCoCrAlYHf lower bonding layer Upper bonding layer;

[0097] The process of the supersonic flame spraying is as follows: fuel flow rate 60mL·min -1 , oxygen flow rate 250mL·min -1 , spraying distance 160mm, powder feeding rate 6kg·h -1 ;

[0098] Step 4: Use atmospheric plasma spraying to spray the ceramic layer powder on A ceramic layer is formed on the surface of the upper bonding layer.

[0099] The atmospheric plasma spraying process is as follows: current 550A, voltage 73V, spraying distance 80cm, powder feeding rate 40g·min -1 .

[0100] Example 4:

[0101] The preparation method of the thermal barrier coating having a double bonding layer structure of this embodiment is carried out according to the following steps:

[0102] Step 1: Pre-treat the substrate and spray powder separately;

[0103] The substrate is a nickel-based high-temperature alloy;

[0104] The spraying powder is NiCoCrAlYHf powder, Powder and ceramic layer powder; the ceramic layer powder is 8YSZ ceramic powder;

[0105] In the NiCoCrAlYHf powder, the content of Ni is 54 wt %, the content of Co is 13 wt %, the content of Cr is 21 wt %, the content of Al is 11 wt %, the content of Y is 0.5 wt %, and the content of Hf is 0.5 wt %.

[0106] The median diameter of the NiCoCrAlYHf powder is 13.57 μm; The median diameter of the powder is 25.33 μm; the median diameter of the ceramic layer powder is 63.25 μm;

[0107] The pretreatment of the substrate includes grinding, sandblasting and cleaning to improve the bonding strength between the coating and the substrate; 100#, 500#, 1000# and 3000# SiC sandpaper are used in sequence during grinding; the sandblasting medium used in the sandblasting is chrome steel sand, the sandblasting pressure is 0.6MPa, and the sandblasting distance is 200mm; the cleaning is performed by ultrasonic cleaning of the substrate with anhydrous ethanol;

[0108] The pretreatment of the spray powder is a drying process to remove the moisture contained in the spray powder and increase the fluidity of the powder; the drying process temperature is 80°C and the time is 12 hours;

[0109] Step 2: using supersonic flame spraying to spray NiCoCrAlYHf powder on the surface of the substrate to form a NiCoCrAlYHf lower bonding layer;

[0110] The process of the supersonic flame spraying is as follows: fuel flow rate 21L·h -1 , oxygen flow rate 876L·min -1 , spraying distance 300mm, powder feeding rate 75g·min -1 ;

[0111] Step 3: Use supersonic flame spraying to Powder spraying is formed on the surface of NiCoCrAlYHf lower bonding layer Upper bonding layer;

[0112] The process of the supersonic flame spraying is as follows: fuel flow rate 70mL·min -1 , oxygen flow rate 240mL·min -1 , spraying distance 180mm, powder feeding rate 5kg·h -1 ;

[0113] Step 4: Use atmospheric plasma spraying to spray the ceramic layer powder on A ceramic layer is formed on the surface of the upper bonding layer.

[0114] The atmospheric plasma spraying process is as follows: current 550A, voltage 73V, spraying distance 90cm, powder feeding rate 45g·min-1 .

[0115] Comparative Example 1:

[0116] The preparation method of the thermal barrier coating of this embodiment is carried out according to the following steps:

[0117] Step 1: Pre-treat the substrate and spray powder separately;

[0118] The substrate is a nickel-based high-temperature alloy;

[0119] The spraying powder is Powder and ceramic layer powder; the ceramic layer powder is 8YSZ ceramic powder;

[0120] described The median diameter of the powder is 25.33 μm; the median diameter of the ceramic layer powder is 63.25 μm;

[0121] The pretreatment of the substrate includes grinding, sandblasting and cleaning to improve the bonding strength between the coating and the substrate; 100#, 500#, 1000# and 3000# SiC sandpaper are used in sequence during grinding; the sandblasting medium used in the sandblasting is chrome steel sand, the sandblasting pressure is 0.6MPa, and the sandblasting distance is 200mm; the cleaning is performed by ultrasonic cleaning of the substrate with anhydrous ethanol;

[0122] The pretreatment of the spray powder is a drying process to remove the moisture contained in the spray powder and increase the fluidity of the powder; the drying process temperature is 80°C and the time is 12 hours;

[0123] Step 2: Use supersonic flame spraying to Powder spraying forms on the surface of the substrate Adhesive layer;

[0124] The process of the supersonic flame spraying is as follows: fuel flow rate 70mL·min -1 , oxygen flow rate 240mL·min -1 , spraying distance 180mm, powder feeding rate 5kg·h -1 ;

[0125] Step 3: Use atmospheric plasma spraying to spray the ceramic layer powder onto A ceramic layer is formed on the surface of the bonding layer.

[0126] The atmospheric plasma spraying process is as follows: current 550A, voltage 73V, spraying distance 80cm, powder feeding rate 40g·min -1 .

[0127] Comparative Example 2:

[0128] The preparation method of the thermal barrier coating of this embodiment is carried out according to the following steps:

[0129] Step 1: Pre-treat the substrate and spray powder separately;

[0130] The substrate is a nickel-based high-temperature alloy;

[0131] The spraying powder is NiCoCrAlYHf powder and ceramic layer powder; the ceramic layer powder is 8YSZ ceramic powder;

[0132] In the NiCoCrAlYHf powder, the content of Ni is 57wt%, the content of Cr is 12wt%, the content of Al is 10wt%, the content of Y is 0.5wt%, the content of Co is 20, and the content of Hf is 0.5.

[0133] The median diameter of the NiCoCrAlYHf powder is 13.57 μm; the median diameter of the ceramic layer powder is 63.25 μm;

[0134] The pretreatment of the substrate includes grinding, sandblasting and cleaning to improve the bonding strength between the coating and the substrate; 100#, 500#, 1000# and 3000# SiC sandpaper are used in sequence during grinding; the sandblasting medium used in the sandblasting is chrome steel sand, the sandblasting pressure is 0.6MPa, and the sandblasting distance is 200mm; the cleaning is performed by ultrasonic cleaning of the substrate with anhydrous ethanol;

[0135] The pretreatment of the spray powder is a drying process to remove the moisture contained in the spray powder and increase the fluidity of the powder; the drying process temperature is 80°C and the time is 12 hours;

[0136] Step 2: using supersonic flame spraying to spray NiCoCrAlYHf powder on the surface of the substrate to form a NiCoCrAlYHf bonding layer;

[0137] The process of the supersonic flame spraying is as follows: fuel flow rate 21L·h -1 , oxygen flow rate 876L·min -1 , spraying distance 300mm, powder feeding rate 75g·min -1 ;

[0138] Step 3: Using atmospheric plasma spraying to spray ceramic layer powder on the surface of the NiCoCrAlYHf bonding layer to form a ceramic layer.

[0139] The atmospheric plasma spraying process is as follows: current 550A, voltage 73V, spraying distance 80cm, powder feeding rate 40g·min -1 .

[0140] pass Figure 1 、 Figure 3 and Figure 5 It can be seen that the NiCoCrAlYHf lower bonding layer, The upper bonding layer and the 8YSZ ceramic layer both have high phase purity. Figure 2 、 Figure 4 and Figure 6 It can be seen that each layer in the thermal barrier coating prepared in Example 1 has good uniformity and good interface bonding.

[0141] The thermal barrier coatings prepared in Example 1 and Comparative Examples 1-2 were subjected to isothermal oxidation performance tests. After being kept at 1100°C for 50 hours, Figure 7 It can be seen that there is no obvious peeling of the thermal barrier coating in Example 1; Figure 8 It can be seen that the thermal barrier coating in comparative example 1 has interfacial delamination near the diffusion zone / bonding layer interface. The weight gain of the thermal barrier coating in Example 1 during the isothermal oxidation performance test is 1.37×10 -7 g·cm -2 ·h -1 , which is lower than 2.60×10 -7 g·cm -2 ·h -1 .

[0142] In summary, it can be explained that the present invention constructs / NiCoCrAlYHf double bonding layer structure thermal barrier coating system effectively achieves the synergistic optimization of antioxidant performance improvement and mutual diffusion inhibition.

Claims

1. A thermal barrier coating having a double bonding layer structure, characterized in that: The thermal barrier coating with a double bonding layer structure is composed of a ceramic layer and a bonding layer; the bonding layer is composed of a Cr2AlC upper bonding layer and a NiCoCrAlYHf lower bonding layer, and the Cr2AlC upper bonding layer is arranged between the ceramic layer and the NiCoCrAlYHf lower bonding layer; the ceramic layer is 8YSZ ceramic; In the NiCoCrAlYHf lower bonding layer, the content of Ni is 54wt%-71wt%, the content of Co is 0-20wt%, the content of Cr is 12wt%-22wt%, the content of Al is 6wt%-11wt%, the content of Y is 0.5wt%-1wt%, and the content of Hf is 0-0.5wt%.

2. The thermal barrier coating with a double bonding layer structure according to claim 1, characterized in that: The thickness of the NiCoCrAlYHf lower bonding layer is 30-100 μm, the thickness of the Cr2AlC upper bonding layer is 30-100 μm, and the thickness of the ceramic layer is 150-500 μm.

3. The method for preparing a thermal barrier coating having a double bonding layer structure according to claim 1, wherein: The preparation method of the thermal barrier coating having a double bonding layer structure is carried out according to the following steps: Step 1: Pre-treat the substrate and spray powder separately; The spraying powder is NiCoCrAlYHf powder, Cr2AlC powder and ceramic layer powder; the ceramic layer powder is 8YSZ ceramic powder; Step 2: using supersonic flame spraying to spray NiCoCrAlYHf powder on the surface of the substrate to form a NiCoCrAlYHf lower bonding layer; Step 3: Using supersonic flame spraying to spray Cr2AlC powder on the surface of the NiCoCrAlYHf lower bonding layer to form a Cr2AlC upper bonding layer; Step 4: Use atmospheric plasma spraying to spray ceramic layer powder onto the surface of the Cr2AlC upper bonding layer to form a ceramic layer.

4. The method for preparing a thermal barrier coating having a double bonding layer structure according to claim 3, wherein: The substrate in step 1 is a nickel-based high-temperature alloy.

5. The method for preparing a thermal barrier coating having a double bonding layer structure according to claim 3, wherein: The median diameter of the NiCoCrAlYHf powder in step 1 is 13.57 μm; the median diameter of the Cr2AlC powder is 25.33 μm; and the median diameter of the ceramic layer powder is 63.25 μm.

6. The method for preparing a thermal barrier coating having a double bonding layer structure according to claim 3, wherein: The pretreatment of the substrate in step 1 is grinding, sandblasting and cleaning to improve the bonding strength between the coating and the substrate.

7. The method for preparing a thermal barrier coating having a double bonding layer structure according to claim 6, characterized in that: The sandblasting medium used in the sandblasting is chrome steel sand, the sandblasting pressure is 0.5-0.7 MPa, and the sandblasting distance is 180-220 mm; the cleaning uses acetone or anhydrous ethanol to ultrasonically clean the substrate; the pretreatment of the spray powder is a drying treatment to remove moisture contained in the spray powder and increase the fluidity of the powder.

8. The method for preparing a thermal barrier coating having a double bonding layer structure according to claim 3, wherein: The process of supersonic flame spraying in step 2 is as follows: fuel flow rate 19-23L·h -1 , oxygen flow rate 870-880L·min -1 , spraying distance 280-320mm, powder feeding rate 70-80g·min -1 .

9. The method for preparing a thermal barrier coating having a double bonding layer structure according to claim 3, wherein: The process of supersonic flame spraying in step 3 is as follows: fuel flow rate 60-80mL·min -1 , oxygen flow rate 230-250mL·min -1 , spraying distance 140-180mm, powder feeding rate 5-6kg·h -1 .

10. The method for preparing a thermal barrier coating having a double bonding layer structure according to claim 3, wherein: The atmospheric plasma spraying process in step 4 is as follows: current 500-550A, voltage 71-75V, spraying distance 80-100cm, powder feeding rate 36-44g·min -1 .

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