Heat dissipation coating structure of turbine blade of gas turbine and coating forming method

Abstract

The invention discloses a gas turbine blade heat dissipation coating structure and a coating forming method, the coating structure comprises a fixing layer, a bonding layer and a surface layer which are sequentially arranged outwards from the surface of a blade base body, the fixing layer is a first multi-component alloy deposited through electroplating, the physical properties of the blade base body and a heat dissipation coating are matched, stress is eliminated, and the connecting effect is achieved; the bonding layer contains ceramic nanofibers and a second multi-component alloy, the ceramic nanofibers are subjected to polarizable modification treatment and have high thermal conductivity and thermal expansion coefficient matching performance, the surface layer is an extension part of the ceramic nanofibers, the curvature radius of the tip end is small, and therefore the heat radiation effect is enhanced; the thermal stress of the heat dissipation coating and the blade base body in the wide temperature range is effectively eliminated, the thermal radiation coefficient of the surface of the blade base body is enhanced through radiation heat exchange of the high-temperature-resistant ceramic nanofiber tips, the working temperature of the blade base body is remarkably reduced, and the fatigue resistance of the surface of the blade base body is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of gas turbine blade coating structures, and in particular to a gas turbine blade heat dissipation coating structure and a coating forming method. Background Art

[0002] As a key component that rotates at high speed, turbine blades work in a harsh environment of high temperature and high pressure, so high requirements are placed on their cooling technology. The heat dissipation of turbine blades can effectively reduce the temperature of turbine blades and prevent them from deforming, melting or losing performance due to overheating. This is the prerequisite for ensuring the stable operation of the turbine. Good heat dissipation can extend the service life of turbine blades, reduce material fatigue and damage caused by high temperature, and reduce maintenance costs and replacement frequency. In addition, heat dissipation also helps to improve the overall efficiency and performance of the turbine. When the blade temperature is controlled, the thermal efficiency of the turbine will increase accordingly, thereby outputting more power.

[0003] At present, the heat dissipation of gas turbine blades mainly depends on a special coating technology - thermal barrier coating. This coating technology is of great significance for improving the high-temperature oxidation and corrosion resistance of turbine blades and extending their service life. Thermal barrier coatings are usually composed of a metal bonding base layer and a ceramic surface layer. However, this type of thermal barrier coating still has certain limitations in terms of stability and durability under high temperature and high-intensity work. Summary of the invention

[0004] In order to solve the technical problems mentioned in the above background technology, the present invention provides a heat dissipation coating structure and a coating forming method for a gas turbine turbine blade.

[0005] The technical solution of the present invention is as follows: The present invention firstly provides a heat dissipation coating structure for a gas turbine blade, comprising a blade substrate and a fixing layer, a bonding layer and a surface layer which are sequentially arranged on the surface of the blade from the inside to the outside.

[0006] Specifically, the material of the fixing layer includes a first multi-element alloy, the first multi-element alloy includes a first metal element and a second metal element, wherein the grain size of the first metal element is less than 50 nm, the melting point is greater than 1200° C., and the thermal expansion coefficient is greater than 8×10 -6 / K, less than 12×10 -6 / K, thermal conductivity is 70W / (m·K)-200W / (m·K), the grain size of the second metal element is less than 45nm, the melting point is greater than 1800℃, and the thermal expansion coefficient is greater than 6×10 -6 / K, less than 8×10 -6 / K; the material of the bonding layer includes a second multi-element alloy and ceramic nanofibers, wherein the ceramic nanofibers have an aspect ratio of 50-12000, a melting point greater than 3000°C, a thermal conductivity greater than 800W / (m·K), and a thermal expansion coefficient less than 1×10 -5 / K, the second multi-element alloy includes a first metal element and a second metal element; the surface layer is the portion of the ceramic nanofiber in the bonding layer that exceeds the surface of the bonding layer, that is, the extended portion of the ceramic nanofiber in the bonding layer, and the radius of curvature of the tip of the ceramic nanofiber in the surface layer is less than 20nm, wherein the function of the fixing layer is to match the blade substrate in terms of physical properties, and effectively eliminate the stress between the coating and the blade substrate under extreme physical conditions, and at the same time play the role of connecting the blade substrate, and cooperate with the setting of the bonding layer and the surface layer, so that the coating can better radiate heat outward, thereby ensuring the heat dissipation effect of the coating under extreme physical conditions, thereby ensuring the performance of the blade substrate.

[0007] In the above-mentioned heat dissipation coating structure for gas turbine blades, in order to ensure that the bonding layer can better adhere to the blade substrate and thus ensure the heat conduction effect therethrough, the mass ratio of the first metal element to the second metal element in the first multi-element alloy is 1:1.5-1:3.5.

[0008] As a preferred implementation, in order to ensure the connection effect and stability of the fixing layer and the thermal conductivity thereof, the thickness of the fixing layer is 10-200 nm.

[0009] In the heat dissipation coating structure of a gas turbine blade as described above, in order to ensure the bonding effect between the bonding layer and the fixing layer, and at the same time ensure the heat dissipation effect through the ceramic nanofibers, the mass ratio of the first metal element to the second metal element in the second multi-component alloy is 2:1-1:2.5, and the mass ratio of the ceramic nanofibers to the second multi-component alloy is 1:1-1:3.5.

[0010] As a preferred embodiment, in order to ensure the heat conduction effect of the bonding layer and thus ensure that the heat can be better dissipated through the surface layer, the thickness of the bonding layer is 0.8-30 μm.

[0011] As a further preference, in order to further ensure the heat dissipation effect through the surface layer, the ceramic nanofibers in the bonding layer and the surface layer have an orientation degree perpendicular to the surface of the blade substrate, and the proportion of fibers with a normal deviation angle less than 30° is not less than 40%.

[0012] The present invention also provides a coating molding method for the coating molding work of the above-mentioned gas turbine turbine blade heat dissipation coating structure, and the coating molding method comprises at least the following steps: S1: Preparation; Thoroughly clean the surface of the blade substrate to be coated; S2: Processing of the fixing layer; The cleaned blade substrate is placed in an electroplating tank, and a fixing layer having a first preset thickness is deposited on the surface of the blade substrate by an electroplating method; The electroplating tank contains a first metal element and a second metal element in a first preset ratio; S3: Processing of bonding layer; S3.1: cleaning the blade substrate with the fixing layer; S3.2: placing the cleaned blade substrate into an electrolytic tank, and depositing a second bonding layer of a preset thickness on the surface of the fixing layer by an electroplating method; The electrolytic cell contains polarizable ceramic nanofibers and a second multi-component alloy in a second preset ratio by mass, and the mass ratio of the first metal element to the second metal element in the second multi-component alloy satisfies a third preset ratio; The polarizable ceramic nanofibers are obtained by polarization modification based on the characteristics consistent with the ceramic nanofibers in the binding layer; S4: processing of the surface layer; The surface layer is naturally obtained by cleaning the leaf substrate containing the fixing layer and the binding layer in sequence and removing moisture; S5: heat treatment; The blade substrate including the fixing layer, the bonding layer and the surface layer in sequence is calcined at a preset temperature for 70-80 minutes.

[0013] In the coating molding method as described above, in order to ensure the fixing strength of the polarizable ceramic nanofibers in the bonding layer while allowing the heat to be effectively dissipated through the polarizable ceramic nanofibers in the surface layer, in step S3.2, the mass fraction of the polarizable ceramic nanofibers is 0.5%-0.8%.

[0014] Furthermore, in step S3.2, the polarization method is to deposit an aluminum coating on the surface of the ceramic nanofibers by vacuum evaporation.

[0015] In the coating forming method as described above, in order to ensure that the coating has a higher strength after coating, so that it can be more adaptable to high-intensity working conditions, in step S5, the preset temperature is 1600°C.

[0016] The beneficial effects of the present invention are as follows: the present invention is a heat dissipation coating structure and coating molding method for gas turbine turbine blades. By designing a heat dissipation coating comprising a fixing layer, a bonding layer, and a surface layer, the thermal stress between the heat dissipation coating and the blade substrate under a wide temperature range is effectively eliminated. The thermal radiation coefficient of the blade substrate surface is enhanced by the radiation heat exchange at the tip of the high-temperature resistant ceramic nanofiber, and the operating temperature of the blade substrate is significantly reduced. The fixing layer in the heat dissipation coating strengthens the microscopic crystalline structure of the blade substrate surface, improves the fatigue resistance of the blade substrate surface, and ultimately extends the service life of the blade substrate, thereby better ensuring the performance of the blade substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] By reading the detailed description of the preferred embodiment below, the scheme and advantages of the present application will become clear to those skilled in the art. The accompanying drawings are only for the purpose of illustrating the preferred embodiment and are not to be considered as limiting the present invention.

[0018] In the attached picture: Figure 1 A schematic diagram of the steps of the coating molding method in the embodiment; Figure 2 A schematic diagram of the specific steps of processing the fixing layer in the embodiment; Figure 3 Schematic diagram of the specific steps of bonding layer processing in the embodiment. DETAILED DESCRIPTION

[0019] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings.

[0020] Embodiment: This embodiment first provides a heat dissipation coating structure for a gas turbine blade, including a blade substrate and a fixing layer, a bonding layer and a surface layer arranged in sequence from the inside to the outside on the surface of the blade.

[0021] First of all, regarding the fixing layer, its function is to match the blade substrate in terms of physical properties and effectively eliminate the stress between the coating and the blade substrate under extreme physical conditions, while also connecting the blade substrate. On this basis, the material of the fixing layer includes a first multi-component alloy, and the first multi-component alloy includes a first metal element and a second metal element.

[0022] The first metal element has a grain size of less than 50 nm, a melting point of greater than 1200°C, and a thermal expansion coefficient of greater than 8×10 -6 / K, less than 12×10 -6 / K, the thermal conductivity is 70W / (m·K)-200W / (m·K). In this embodiment, the first metal element is the metal element beryllium (Be), the grain size of which is 48 nanometers, the melting point is 1283°C, and the thermal expansion coefficient is 11.6×10 -6 / K, thermal conductivity is 190W / (m·K).

[0023] Furthermore, the second metal element has a grain size of less than 45 nm, a melting point of greater than 1800° C., and a thermal expansion coefficient of greater than 6×10 -6 / K, less than 8×10 -6 / K, in this embodiment, the second metal element is a metal element tantalum (Ta), which has a grain size of 40 nanometers, a melting point of 2996°C, and a thermal expansion coefficient of 6.5×10 -6 / K.

[0024] As a preferred implementation manner in this embodiment, in order to ensure that the bonding layer can better adhere to the blade substrate and thus ensure the heat conduction effect therethrough, the mass ratio of the first metal element to the second metal element in the first multi-element alloy is 1:1.5-1:3.5.

[0025] As a further preference, in order to ensure the connection effect and stability of the fixing layer and the thermal conductivity thereof, the thickness of the fixing layer is 10-200 nm, preferably 20 nm.

[0026] In terms of the bonding layer, its material includes a second multi-component alloy and ceramic nanofibers, wherein the second multi-component alloy includes a first metal element and a second metal element, and the ceramic nanofibers have an aspect ratio of 50-12000, a melting point greater than 3000°C, a thermal conductivity greater than 800W / (m·K), and a thermal expansion coefficient less than 1×10 -5 / K.

[0027] Finally, as for the surface layer, it is the part of the ceramic nanofiber in the bonding layer that exceeds the surface of the bonding layer, that is, the extended part of the ceramic nanofiber in the bonding layer, and the curvature radius of the tip of the ceramic nanofiber in the surface layer is less than 20nm. The coordinated arrangement of the fixing layer, the bonding layer and the surface layer effectively eliminates the thermal stress between the heat dissipation coating and the blade substrate under a wide temperature range, and enhances the thermal radiation coefficient of the blade substrate surface through the radiation heat exchange of the high-temperature resistant ceramic nanofiber tips, so that the coating can better radiate heat outward, significantly reducing the working temperature of the blade substrate, and enhancing the microcrystalline structure of the blade substrate surface through the fixing layer in the heat dissipation coating, thereby improving the fatigue resistance of the blade substrate surface, and ultimately ensuring the heat dissipation effect of the coating under extreme physical conditions, extending the service life of the blade substrate, and better ensuring the performance of the blade substrate.

[0028] As a preferred embodiment, in order to ensure the bonding effect between the bonding layer and the fixing layer, and at the same time ensure the heat dissipation effect through the ceramic nanofibers, the mass ratio of the first metal element to the second metal element in the second multi-component alloy is 2:1-1:2.5, and the mass ratio of the ceramic nanofibers to the second multi-component alloy is 1:1-1:3.5.

[0029] As a further preference, in order to ensure the heat conduction effect of the bonding layer and thus ensure that the heat can be better dissipated through the surface layer, the thickness of the bonding layer is 0.8-30 μm.

[0030] More preferably, in order to further ensure the heat dissipation effect through the surface layer, the ceramic nanofibers in the bonding layer and the surface layer have an orientation perpendicular to the surface of the blade substrate, and the proportion of fibers with a normal deviation angle less than 30° is not less than 40%.

[0031] This embodiment also provides a coating molding method for the coating molding work of the above-mentioned gas turbine turbine blade heat dissipation coating structure, see Figure 1 , including S1: preparation, S2: processing of the fixing layer, S3: processing of the bonding layer, S4: processing of the surface layer and S5: heat treatment steps. Figure 2 and attached Figure 3 The steps of the coating molding method are described in detail.

[0032] In this embodiment, the coating forming method specifically includes the following steps: S1: Preparation; Thoroughly clean the surface of the blade substrate to be coated; S2: Processing of the fixing layer; S2.1: A first electroplating solution is provided in an electroplating tank, wherein the first electroplating solution contains a first metal element and a second metal element in a first preset ratio, wherein the first preset ratio is in a range of 1:1-1:3.5; S2.2: placing the cleaned blade substrate into an electroplating tank, and depositing a fixing layer of a first preset thickness on the surface thereof by an electroplating method, wherein the first preset thickness is in the range of 10-200 nm, preferably 20 nm; S3: Processing of bonding layer; S3.1: cleaning the blade substrate with the fixing layer; S3.2: forming a bonding layer on the surface of the fixing layer by electroplating; S3.2.1: Preparation of polarizable ceramic nanofibers; The polarizable ceramic nanofibers are obtained by polarization modification based on the characteristics consistent with the ceramic nanofibers in the binding layer, and the polarization method is to evaporate an aluminum coating on the surface of the ceramic nanofibers by vacuum evaporation; S3.2.2: A second electroplating solution is provided in the electrolytic cell, wherein the second electroplating solution contains ceramic nanofibers and a second multi-component alloy in a second preset ratio by mass, and the second preset ratio is in a range of 1:1-1:3.5, and the mass ratio of the first metal element to the second metal element in the second multi-component alloy is in a third preset ratio, and the third preset ratio is in a range of 2:1-1:2.5; In order to ensure the fixation strength of the polarizable ceramic nanofibers in the bonding layer while allowing the heat to be effectively dissipated through the polarizable ceramic nanofibers in the surface layer, the mass fraction of the polarizable ceramic nanofibers in the second electroplating solution is 0.5%-0.8%; S3.2.3: placing the cleaned blade substrate into an electrolytic cell, and depositing a second preset thickness of a bonding layer on the surface of the fixing layer by electroplating, wherein the second preset thickness is within a range of 0.8-30 μm; S4: processing of the surface layer; The surface layer is naturally obtained by cleaning the leaf substrate containing the fixing layer and the binding layer in sequence and removing moisture; S5: heat treatment; The blade substrate containing the fixing layer, the bonding layer and the surface layer in sequence is calcined at a preset temperature for 70-80 minutes. In order to ensure that the coating has a higher strength after coating, so that it can better adapt to high-intensity working conditions, the preset temperature is preferably 1600°C.

Claims

1. A heat dissipation coating structure for a gas turbine blade, characterized in that: It includes a blade substrate and a fixing layer, a bonding layer and a surface layer arranged in sequence from the inside to the outside on its surface; The material of the fixing layer includes a first multi-element alloy, wherein the first multi-element alloy includes a first metal element and a second metal element, wherein the grain size of the first metal element is less than 50 nm, the melting point is greater than 1200° C., and the thermal expansion coefficient is greater than 8×10 -6 / K, less than 12×10 -6 / K, thermal conductivity is 70W / (m·K)-200W / (m·K), the grain size of the second metal element is less than 45nm, the melting point is greater than 1800℃, and the thermal expansion coefficient is greater than 6×10 -6 / K, less than 8×10 -6 / K; The material of the bonding layer includes a second multi-element alloy and ceramic nanofibers, wherein the ceramic nanofibers have an aspect ratio of 50-12000, a melting point greater than 3000°C, a thermal conductivity greater than 800W / (m·K), and a thermal expansion coefficient less than 1×10 -5 / K, the second multi-element alloy includes a first metal element and a second metal element; The surface layer is the portion of the ceramic nanofibers in the bonding layer that extends beyond the surface of the bonding layer, and the radius of curvature of the tips of the ceramic nanofibers in the surface layer is less than 20 nm.

2. A gas turbine blade heat dissipation coating structure according to claim 1, characterized in that: The mass ratio of the first metal element to the second metal element in the first multi-element alloy is 1:1.5-1:3.

5.

3. The heat dissipation coating structure of a gas turbine blade according to claim 1, characterized in that: The thickness of the fixing layer is 10-200 nm.

4. The heat dissipation coating structure for gas turbine blades according to claim 1, characterized in that: The mass ratio of the first metal element to the second metal element in the second multi-component alloy is 2:1-1:2.5, and the mass ratio of the ceramic nanofiber to the second multi-component alloy is 1:1-1:3.

5.

5. The heat dissipation coating structure of a gas turbine blade according to claim 1, characterized in that: The thickness of the bonding layer is 0.8-30 μm.

6. The heat dissipation coating structure for gas turbine blades according to claim 1, characterized in that: The ceramic nanofibers in the bonding layer and the surface layer have an orientation degree perpendicular to the surface of the blade substrate, and the proportion of fibers with a normal deviation angle less than 30° is not less than 40%.

7. A coating molding method, used for a heat dissipation coating structure of a gas turbine blade according to any one of claims 1 to 5, characterized in that: At least the following steps are included: S1: Preparation; Thoroughly clean the surface of the turbine blade substrate to be coated; S2: Processing of the fixing layer; The cleaned blade substrate is placed in an electroplating tank, and a fixing layer having a first preset thickness is deposited on the surface of the blade substrate by an electroplating method; The electroplating tank contains a first metal element and a second metal element in a first preset ratio; S3: Processing of bonding layer; S3.1: cleaning the blade substrate with the fixing layer; S3.2: placing the cleaned blade substrate into an electrolytic tank, and depositing a second bonding layer of a preset thickness on the surface of the fixing layer by an electroplating method; The electrolytic cell contains polarizable ceramic nanofibers and a second multi-component alloy in a second preset ratio by mass, and the mass ratio of the first metal element to the second metal element in the second multi-component alloy satisfies a third preset ratio; The polarizable ceramic nanofibers are obtained by polarization modification based on the characteristics consistent with the ceramic nanofibers in the binding layer; S4: processing of the surface layer; The surface layer is naturally obtained by cleaning the leaf substrate containing the fixing layer and the binding layer in sequence and removing moisture; S5: heat treatment; The blade substrate including the fixing layer, the bonding layer and the surface layer in sequence is calcined at a preset temperature for 70-80 minutes.

8. A coating forming method according to claim 7, characterized in that: In step S3.2, the mass fraction of the polarizable ceramic nanofibers is 0.5%-0.8%.

9. A coating molding method according to claim 7, characterized in that: In step S3.2, the polarization method is to deposit an aluminum coating on the surface of the ceramic nanofibers by vacuum evaporation.

10. A coating molding method according to claim 7, characterized in that: In step S5, the preset temperature is 1600°C.

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