Method for preparing thermal barrier coating interface three-dimensional texture with assistance of mask plate

Abstract

The invention relates to a method for preparing a thermal barrier coating interface three-dimensional texture with the assistance of a mask plate, and the method comprises the following steps: depositing a texture layer on the surface of a bonding layer by adopting a metal mask plate auxiliary spraying technology: placing a metal mask plate, and then carrying out plasma spraying or high velocity oxy-fuel spraying on the surface of the bonding layer to obtain the thermal barrier coating interface three-dimensional texture with the assistance of the metal mask plate; and a texture layer is prepared on the surface of the bonding layer through spraying, and after the metal mask plate is removed, the three-dimensional texture of the needed structure is obtained. Compared with the prior art, in the spraying process of the bonding layer, a layer of metal mask plate is added on the surface of the bonding layer, rapid and simple three-dimensional texture construction is achieved in a continuous spraying mode, and therefore the stability of the coating is improved, and the service life of the coating is prolonged.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of thermal barrier coating, in particular to a method for preparing thermal barrier coating interface three-dimensional texture assisted by mask. BACKGROUND

[0002] Heavy-duty gas turbines are the core equipment in the field of power generation and driving. Advanced thermal barrier coating technology is considered to be the core of improving the efficiency of gas turbines. At present, the widely used thermal barrier coating includes a low thermal conductivity ceramic layer, a metal bonding layer, a high-temperature alloy substrate layer, and a thermal growth oxide layer formed under high-temperature oxidation conditions. However, during long-term thermal service, due to the thermal expansion coefficients of the ceramic layer and the bonding layer, as well as the brittle oxides and pores formed by the oxidation of the bonding layer interface, cracks may be generated, expanded and merged at the (near) interface, and eventually lead to the failure of the coating. Therefore, improving the stability of the coating interface and the near interface is the key to improving the service life of the thermal barrier coating.

[0003] At present, sandblasting treatment is performed on the substrate surface to improve the interface roughness, which is the most common method. However, the roughness obtained by sandblasting treatment is generally low (the average roughness is less than 20 μm), which is difficult to effectively block the expansion of the (near) interface cracks, and its effect of improving the interface stability is limited. The latest technical methods, such as Chinese patent ZL201410797898.X and Chinese patent CN202310216175.5, propose to use coaxial laser powder feeding and laser selective melting technology to realize the construction of three-dimensional structure of the thermal barrier coating interface. The research results show that the three-dimensional texture can increase the contact area between the ceramic layer and the bonding layer, promote the mechanical interlocking between the interfaces, and effectively block the expansion and merging of the interface and near interface cracks, thereby significantly improving the interface stability of the coating. However, the technical methods have the following disadvantages: (1) The process is complex, the cost is high, and pollution is easy to occur: the laser remelting or coaxial powder feeding technology needs to be additionally used on the basis of the preparation of the thermal barrier coating, which leads to complex process, high cost, and easy to cause sample pollution. (2) The laser coaxial powder feeding technology is difficult to realize the construction of higher precision and smaller size three-dimensional texture, which will lead to the increase of the roughness of the coating surface, is not conducive to the formation of the air film on the blade surface, and limits its application. (3) The laser cladding process has high requirements for the flatness of the substrate, and cannot be realized on the curved surface or complex shape surface. SUMMARY

[0004] The purpose of the present application is to overcome the defects of the prior art and provide a method for preparing thermal barrier coating interface three-dimensional texture assisted by mask, which adds a layer of metal mask on the surface of the bonding layer during the spraying process, realizes rapid and simple three-dimensional texture construction through continuous spraying, and improves the stability and service life of the coating.

[0005] The present application can be realized by the following technical solutions:

[0006] The present application aims to provide a method for preparing thermal barrier coating interface three-dimensional texture with mask assistance, which comprises the following steps:

[0007] depositing a texture layer on the surface of the bond coat by using metal mask assisted spraying technology: placing a metal mask, then using plasma spraying technology or high velocity oxygen fuel spraying technology to spray and prepare a texture layer on the surface of the bond coat, and after removing the metal mask, a three-dimensional texture with the desired structure is obtained.

[0008] Further, the method comprises the following steps: designing and preparing a metal mask with a three-dimensional structure, placing the metal mask on the surface of the bond coat or directly in front of it, and then using plasma spraying technology or high velocity oxygen fuel spraying technology to spray and prepare a metal layer with a certain thickness on the surface of the bond coat, and after removing the mask, a three-dimensional texture with the desired structure is obtained.

[0009] Further, the metal mask is placed on the surface of the bond coat or directly in front of it.

[0010] Further, the method comprises the following steps:

[0011] depositing a bond coat on the surface of the metal substrate by using plasma spraying or high velocity oxygen fuel spraying technology;

[0012] depositing a texture layer on the surface of the bond coat by using metal mask assisted spraying technology;

[0013] depositing a ceramic layer on the surface of the texture layer by using plasma spraying or suspension plasma spraying technology.

[0014] Further, the metal substrate is obtained after cleaning, degreasing and sandblasting treatment of the superalloy substrate. The present application does not have any special limitations on the process of the cleaning, degreasing and sandblasting treatment, and the methods well known to those skilled in the art can be used.

[0015] Further, the texture layer is prepared by plasma spraying process or high velocity oxygen fuel spraying method, wherein the basic parameters of plasma spraying are: spraying voltage 80-180V, current 50-500A, spraying gun moving speed 500-2000mm / s, spraying distance 100-280mm, powder feeding rate 10-100g / min, Ar flow rate 30-120L / min, H2 flow rate 550L / min. The parameters of high velocity oxygen fuel spraying are: air pressure 70-100PSI, hydrogen pressure 20-50PSI, nitrogen pressure 10-30PSI, propane pressure 20-100PSI, spraying gun moving speed 10-50mm / s, spraying gun distance 10-30cm, powder feeder rotating speed: 1-10r / min.

[0016] Further, the preparation method of the ceramic layer includes but is not limited to atmospheric plasma spraying and suspension plasma spraying.

[0017] Further, the method includes the following steps:

[0018] S1: cleaning, degreasing and sandblasting treatment of the high-temperature alloy substrate;

[0019] S2: depositing a metal bonding layer on the surface of the metal substrate by plasma spraying or high-velocity oxygen fuel spraying technology;

[0020] S3: depositing a textured layer on the surface of the bonding layer by metal mask-assisted spraying technology;

[0021] S4: depositing a ceramic layer on the surface of the textured layer by plasma spraying or suspension plasma spraying technology.

[0022] Further, the high-temperature alloy substrate is preferably one of an iron-based high-temperature alloy substrate, a nickel-based high-temperature alloy substrate or a cobalt-based high-temperature alloy substrate.

[0023] Further, the composition of the ceramic layer includes but is not limited to one or more of yttrium-stabilized zirconia, rare earth zirconate, rare earth tantalate and rare earth magnesium aluminate.

[0024] Further, the preparation raw material of the bonding layer includes but is not limited to one or more of NiCoCrAlY / or NiCrAlY powder, preferably NiCoCrAlY powder.

[0025] Further, the particle size of the preparation raw material of the bonding layer is preferably 20-150 μm, more preferably 30-100 μm, and most preferably 40-90 μm.

[0026] Further, the shape of the three-dimensional texture includes but is not limited to one or more of dot-like, columnar, strip-like, dendritic, wavy and sawtooth structures.

[0027] Further, the pitch of the three-dimensional texture is preferably 0.1-100 mm, more preferably 1-50 mm, and most preferably 2-15 mm.

[0028] Further, the height of the three-dimensional texture is preferably 20-1500 μm, more preferably 30-500 μm, and most preferably 50-150 μm.

[0029] Further, the width of the three-dimensional texture is preferably 20-1500 μm, more preferably 30-500 μm, and most preferably 50-150 μm.

[0030] Further, the length of the three-dimensional texture is preferably 0.01-100 mm, more preferably 0.3-50 mm, and most preferably 0.5-15 mm.

[0031] Further, the included angle of the three-dimensional texture is preferably 0-180°, more preferably 30-160°, and most preferably 40-90°.

[0032] Further, the raw material for preparing the texture layer includes, but is not limited to, NiCoCrAlY and / or NiCrAlY powder, preferably NiCoCrAlY powder.

[0033] Further, the thickness of the bonding layer is preferably 50-1000 μm, more preferably 80-500 μm, and most preferably 100-300 μm.

[0034] Further, the metal mask is placed on the surface of the bonding layer by an external clamp or spot welding method, or between the bonding layer and the spray gun.

[0035] Further, the metal mask can be a metal mask of metal iron-based or nickel-based, and the surface does not need to be specially treated.

[0036] Preferably, the metal mask is placed on the surface of the bonding layer.

[0037] Further, the raw material for preparing the texture layer is consistent with the bonding layer.

[0038] Further, the preparation method of the texture layer is consistent with the preparation method of the bonding layer.

[0039] Compared with the prior art, the present application has the following beneficial effects:

[0040] The method for preparing the three-dimensional texture of the thermal barrier coating interface assisted by the mask provided by the technical solution can realize the printing of the three-dimensional texture of the thermal barrier coating interface by means of the metal mask and the spraying technology. The structure can increase the mechanical interlocking of the metal bonding layer and the ceramic layer interface, realize “interlocking”, and can block the expansion and combination of the interface cracks, so as to greatly improve the interface bonding strength and service life of the coating. Meanwhile, compared with the coaxial powder feeding and laser selective melting technology, the mask-assisted spraying technology can effectively avoid the sample pollution, size deviation and process consistency problems generated in the sample transfer process after the preparation of the bonding layer, and can realize the integrated forming of the bonding layer and the interface texture layer, and has the advantages of low process cost, simple process, good repeatability, high forming degree and no pollution. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1A schematic diagram of a device for preparing a three-dimensional textured surface of an adhesive layer using a metal mask-assisted spraying method. In the diagram, 1 is the spray gun, 2 is the feed inlet, 3 is the molten metal particles, 4 is the high-temperature alloy substrate, 5 is the adhesive layer, 6 is the metal mask, 7 is the plasma beam, 8 is the cooling water, and 9 is the inert gas.

[0042] Figure 2 This is a schematic diagram of the surface textures: point texture, columnar texture, dendritic texture, and sawtooth texture. Where s is the texture spacing, w is the texture width, l is the texture length, and θ is the texture angle. Specifically, a represents point texture, b represents columnar texture, c represents dendritic texture, and d represents sawtooth texture.

[0043] Figure 3 This is a schematic diagram of a cross-section of a thermal barrier coating with a textured interface. In this diagram, 10 is the ceramic layer, 11 is the textured layer, 12 is the metal bonding layer, and 13 is the high-temperature alloy substrate layer. Detailed Implementation

[0044] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0045] The metal mask can be an iron-based or nickel-based metal mask, and its surface does not require special treatment.

[0046] In this invention, any component models, material names, connection structures, control methods, etc., not explicitly stated are considered common technical features disclosed in the prior art.

[0047] like Figure 2 The diagram shows surface schematics of point texture (a), columnar texture (b), dendritic texture (c), and sawtooth texture (d). Here, s is the texture spacing, w is the texture width, l is the texture length, and θ is the texture angle. The point texture, columnar texture, and dendritic texture are discrete textures, but with different levels of gradation; the sawtooth texture is a continuous texture. Different textures have different effects on the crack propagation trajectory.

[0048] Example 1

[0049] This embodiment provides a method for mask-assisted preparation of three-dimensional textures at the interface of thermal barrier coatings, including the following steps:

[0050] The Hastelloy B-2 high-temperature alloy substrate was ultrasonically cleaned for 30 min, degreased with acetone, and sandblasted. The sandblasting pressure was 0.5 MPa, the main component of the sand particles was Al2O3, and the particle size was 50 mesh. Then, NiCoCrAlY powder (particle size 30–100 μm) was sprayed onto the alloy substrate using atmospheric plasma spraying to deposit a NiCoCrAlY binder layer. During the spraying process, the power was 60 kW, the arc current was 400 A, the Ar flow rate was 90 L / min, the H2 flow rate was 16 L / min, the spraying distance was 90 mm, the spray gun moving speed was 800 mm / s, the powder feed rate was 10 g / min, and the number of sprays was 4. The resulting binder layer thickness was 150 μm. A metal mask with discrete circular holes was placed in front of the binder layer, and then a textured layer with a thickness of 150 μm (h = 150 μm) was prepared using atmospheric plasma spraying. The metal mask has a fractal length l of 3 mm, a square shape, a width w of 120 μm, and a thickness of 2 mm. The atmospheric plasma spraying process is consistent with the bonding layer preparation process. After removing the metal mask, a discrete point-like three-dimensional texture (NiCoCrAlY textured layer) is obtained. Subsequently, an atmospheric plasma spraying method is used to deposit a 200 μm thick yttrium-stabilized zirconia (YSZ) ceramic layer on the surface of the obtained three-dimensional textured metal bonding layer to obtain a thermal barrier coating. The spraying parameters are: voltage 85 V, current 70 A, spray gun movement speed 700 mm / s, spraying distance 12 mm, powder feed rate 30 g / min, Ar flow rate 45 NL / min, H2 flow rate 5 NL / min, and 14 spraying times. The interfacial bonding strength between the untextured thermal barrier coating of Comparative Example 1 and the discrete point-textured thermal barrier coating of this embodiment is measured by tensile testing. Tensile results show that, compared to the non-interface textured coating (23.3 MPa), the interfacial bonding strength of the discrete-point textured coating can be increased to 63.9 MPa, an improvement of 174%. Figure 3 The diagram shows a cross-sectional view of a thermal barrier coating with a textured interface. The metal bonding layer 12 is located on the high-temperature alloy substrate 13 (high-temperature alloy substrate), the textured layer 11 is deposited on the metal bonding layer 12 (bonding layer), and the ceramic layer 10 is deposited on the textured layer 11 on which the metal bonding layer 12 is deposited.

[0051] like Figure 1 The diagram shows a schematic of a device for preparing a three-dimensional texture on the surface of an adhesive layer using a metal mask-assisted spraying method. Molten metal particles 3 are sprayed out from the feed inlet, cooling water 8 flows into the spray gun 1, and inert gas 9 is introduced into the spray gun 1. The spray gun 1 sprays out a plasma beam 7, which combines with the molten metal particles 3. Some of the molten metal particles 3 pass through the holes on the metal mask 6 and are deposited on the surface of the adhesive layer 5. The adhesive layer 5 is deposited on the surface of the high-temperature alloy substrate 4. The metal mask 6 is placed in front of the adhesive layer 5.

[0052] Example 2

[0053] The difference between the present embodiment and the specific embodiment 1 is that the shape of the metal mask is sawtooth shape. The other steps are the same as the specific embodiment 1. The present embodiment provides a method for preparing a thermal barrier coating interface three-dimensional texture assisted by a mask, comprising the following steps:

[0054] The Hastelloy B-2 high-temperature alloy substrate was ultrasonically cleaned for 30 min, deoiled with acetone, and sandblasted. The sandblasting pressure was 0.5 MPa, and the main component of the sand particles was Al2O3, and the particle size was 50 mesh. Then, a NiCoCrAlY powder (particle size of 30-100 μm) was sprayed on the alloy substrate by atmospheric plasma spraying to deposit a NiCoCrAlY bonding layer. During the spraying process, the power was 60 KW, the arc current was 400 A, the Ar flow rate was 90 L / min, the H2flow rate was 16 L / min, the spraying distance was 90 mm, the spraying gun moving speed was 800 mm / s, the powder feeding rate was 10 g / min, and the spraying times were 4. The thickness of the obtained bonding layer was 150 μm. A metal mask with continuous sawtooth was placed in front of the bonding layer, and then a textured layer with a thickness of 150 μm was prepared by atmospheric plasma spraying. The metal mask had a middle distance s of 3 mm, an included angle of 60°, a width w of 120 μm, a length l of 5 mm, and a mask thickness of 2 mm. The atmospheric plasma spraying process was consistent with the preparation process of the bonding layer. After the metal mask was removed, a sawtooth textured layer (NiCoCrAlY textured layer) was obtained. Subsequently, a yttrium-stabilized zirconia (YSZ) ceramic layer with a thickness of 200 μm was deposited on the three-dimensional textured surface of the obtained metal bonding layer by atmospheric plasma spraying to obtain a thermal barrier coating. The spraying parameters were as follows: voltage 85 V, current 70 A, spraying gun moving speed 700 mm / s, spraying distance 12 mm, powder feeding rate 30 g / min, Ar flow rate 45 NL / min, H2flow rate 5 NL / min, and spraying times 14. The thermal cycle results at 1100°C showed that the thermal cycle life of the thermal barrier coating with sawtooth texture was increased by 50% compared with the non-textured thermal barrier coating of Comparative Example 1. The metal mask assisted spraying method can low-cost, pollution-free, and quickly realize the construction of the interface textured layer, and the method can be popularized to related other fields.

[0055] Comparative Example 1

[0056] The present comparative example provides a non-textured thermal barrier coating. Compared with Example 1, the present comparative example does not prepare a textured layer with a thickness of 150 μm by atmospheric plasma spraying, but directly deposits a yttrium-stabilized zirconia (YSZ) ceramic layer with a thickness of 200 μm on the surface of the obtained metal bonding layer.

[0057] The foregoing description of the embodiments has been presented for the purpose of illustration and description. It is not intended to be exhaustive or to limit the application to the precise form disclosed. Modifications and variations are possible in light of the above teachings or can be acquired from practice of the application. As well, the description is presented in the context of the preferred embodiments as of their onset and might not represent the scope of the application, and the language sent forth by the claims should be understood to be interpreted in the context of the specification as a whole.

Claims

1. A method for mask-assisted preparation of three-dimensional textures at the interface of a thermal barrier coating, characterized in that, The method includes the following steps: A textured layer is deposited on the surface of the adhesive layer using a metal mask-assisted spraying technique: a metal mask is placed, and then a textured layer is prepared by spraying on the surface of the adhesive layer using plasma spraying or supersonic flame spraying. After removing the metal mask, the desired three-dimensional texture is obtained.

2. The method for preparing a three-dimensional texture of a thermal barrier coating interface with mask assistance according to claim 1, characterized in that, The method includes the following steps: A bonding layer is deposited on the surface of a metal substrate using plasma spraying or supersonic flame spraying technology; A textured layer is deposited on the surface of the adhesive layer using a metal mask-assisted spraying technique. A ceramic layer is deposited on the surface of the textured layer using plasma spraying or suspension plasma spraying techniques.

3. The method for preparing a three-dimensional texture of a thermal barrier coating interface with mask assistance according to claim 2, characterized in that, The metal substrate is obtained by cleaning, degreasing and sandblasting a high-temperature alloy substrate.

4. The method for preparing a three-dimensional texture of a thermal barrier coating interface with mask assistance according to claim 3, characterized in that, The high-temperature alloy matrix is ​​one of iron-based high-temperature alloy matrix, nickel-based high-temperature alloy matrix, or cobalt-based high-temperature alloy matrix.

5. The method for preparing a three-dimensional texture of a thermal barrier coating interface with mask assistance according to claim 2, characterized in that, The ceramic layer comprises one or more of yttrium-stabilized zirconium oxide, rare earth zirconates, rare earth tantalates, and rare earth magnesium aluminates.

6. The method for preparing a three-dimensional texture of a thermal barrier coating interface with mask assistance according to claim 1, characterized in that, The raw materials for preparing the adhesive layer include one or more of NiCoCrAlY or NiCrAlY powder; The particle size of the raw material used to prepare the adhesive layer is 20–150 μm.

7. The method for preparing a three-dimensional texture of a thermal barrier coating interface with mask assistance according to claim 1, characterized in that, The shape of the three-dimensional texture includes one or more of the following: dot-like, columnar, strip-like, tree-like, wavy, and serrated. The spacing of the three-dimensional texture is 0.1–100 mm; The height of the three-dimensional texture is 20–1500 μm; The width of the three-dimensional texture is 20–1500 μm; The length of the three-dimensional texture is 0.01–100 mm; The included angle of the three-dimensional texture is 0 to 180°.

8. The method for preparing a three-dimensional texture of a thermal barrier coating interface with mask assistance according to claim 1, characterized in that, The raw materials for preparing the texture layer include one or more of NiCoCrAlY or NiCrAlY powder.

9. The method for preparing a three-dimensional texture of a thermal barrier coating interface with mask assistance according to claim 1, characterized in that, The thickness of the adhesive layer is 50–1000 μm.

10. The method for preparing a three-dimensional texture of a thermal barrier coating interface with mask assistance according to claim 1, characterized in that, The metal mask is placed on the surface of the adhesive layer or between the adhesive layer and the spray gun by means of external clamping or spot welding.

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