WO2018199237A1

WO2018199237A1 - Thermal barrier coating formation method, thermal barrier coating, and high-temperature member

Info

Publication number: WO2018199237A1
Application number: PCT/JP2018/016998
Authority: WO
Inventors: 芳史岡嶋; 鳥越　泰治
Original assignee: 三菱重工業株式会社
Priority date: 2017-04-26
Filing date: 2018-04-26
Publication date: 2018-11-01
Also published as: DE112018002221T5; US20200048751A1; CN110546296A

Abstract

The thermal barrier coating is provided with a ceramic layer (120) formed on a heat-resistant alloy substrate and containing ceramic substance. The ceramic layer (120) has: a first dense layer (121); an intermediate porous layer (122) laminated on the first dense layer (121), having a higher density than the first dense layer (121), and in which many pores are formed; and a second dense layer (123) laminated on the intermediate porous layer (122) and having a lower density than the intermediate porous layer (122).

Description

Thermal barrier coating formation method, thermal barrier coating, and high temperature member

The present invention relates to a method for forming a thermal barrier coating, a thermal barrier coating, and a high temperature member.
The present application claims priority based on Japanese Patent Application Nos. 2017-087472 and 2017-087471 filed in Japan on April 26, 2017, the contents of which are incorporated herein by reference.

In gas turbines, the temperature of the gas used is set high in order to improve its efficiency. A turbine member such as a moving blade or a stationary blade that is exposed to such high-temperature gas is provided with a thermal barrier coating (TBC) on the surface thereof. The thermal barrier coating is a coating of a thermal spray material having a low thermal conductivity (for example, a ceramic material having a low thermal conductivity) by spraying on the surface of a turbine member that is a sprayed object. By forming the thermal barrier coating on the surface, the temperature of the high temperature member exposed to a high temperature and high pressure environment is lowered and durability is improved.

Patent Document 1 describes a method using suspension plasma spraying as a method of forming a thermal barrier coating on a metal part of a gas turbine engine. In suspension plasma spraying, plasma spraying is performed using a suspension in which microparticles are dispersed in water or an alcohol-based carrier. In suspension plasma spraying, microparticles melted by evaporation or combustion by a plasma jet are deposited on a contact surface. As a result, a homogeneous ceramic layer is formed on the substrate surface by the molten microparticles.

JP2015-166479A

By the way, as a dense ceramic layer in the thermal barrier coating, there is a case where a DVC (Dense Vertical Crack) coating having a vertical split is formed. The erosion resistance is improved because the DVC coating has a dense structure having a vertically divided structure. However, since the DVC coating has a dense structure, it is known that the porosity becomes small and the heat shielding property is lowered. In other words, in the thermal barrier coating, if the porosity is lowered in order to improve the erosion resistance, the thermal conductivity is increased and the thermal barrier performance is lowered.

An object of the present invention is to provide a thermal barrier coating forming method, a thermal barrier coating, and a high-temperature member capable of enhancing a thermal barrier effect while suppressing a decrease in erosion resistance.

The thermal barrier coating according to the first aspect of the present invention is formed on a heat-resistant alloy substrate and includes a ceramic layer containing ceramic, and the ceramic layer is laminated on the first dense layer and the first dense layer. And an intermediate pore layer having a larger density than the first dense layer and having a large number of pores formed thereon, and a second dense layer laminated on the intermediate pore layer and having a density smaller than that of the intermediate pore layer.

According to such a configuration, the intermediate pore layer is formed between the first dense layer and the second dense layer, so that heat input to the ceramic layer in the thickness direction is inhibited by the intermediate pore layer. . As a result, the thermal conductivity as the ceramic layer can be reduced. Furthermore, the adhesiveness with respect to a heat resistant alloy base material is securable by forming a 1st dense layer in the heat resistant alloy base material side in a ceramic layer. Furthermore, erosion resistance can be ensured by forming the second dense layer on the surface side in the ceramic layer.

Further, in the thermal barrier coating according to the second aspect of the present invention, in the first aspect, the first boundary part which is a boundary part between the intermediate pore layer and the first dense layer, the intermediate pore layer and the second dense layer. The porosity may change continuously at the second boundary, which is the boundary with the layer.

Further, in the thermal barrier coating according to the third aspect of the present invention, in the first aspect or the second aspect, the porosity of the intermediate pore layer may be 10% or more and 20% or less.

With such a configuration, the effect of inhibiting heat input to the ceramic layer in the thickness direction is increased over a wide area in the surface direction. As a result, the thermal conductivity in the topcoat layer can be greatly reduced without greatly reducing the erosion resistance in the intermediate pore layer.

In the thermal barrier coating according to the fourth aspect of the present invention, in any one of the first aspect to the third aspect, the porosity of the first dense layer and the second dense layer is 10% or less and 5%. It may be the above.

Moreover, in the thermal barrier coating according to the fifth aspect of the present invention, in any one of the first aspect to the fourth aspect, the first dense layer has a first vertical split extending in the thickness direction dispersed in the surface direction. In the second dense layer, the second vertical division extending in the thickness direction may be dispersed in the surface direction.

In the thermal barrier coating according to the sixth aspect of the present invention, in the fifth aspect, the first vertical split and the second vertical split may extend at an angle with respect to the surface of the ceramic layer. .

By adopting such a configuration, heat input in the thickness direction in the ceramic layer is hindered by the first vertical split and the second vertical split extending obliquely. Therefore, the thermal conductivity in the ceramic layer can be reduced by the first vertical split and the second vertical split. On the other hand, by forming the ceramic layer as densely as the first vertical split and the second vertical split are formed, it is possible to suppress a decrease in erosion resistance.

Further, in the thermal barrier coating according to the seventh aspect of the present invention, in the fifth aspect or the sixth aspect, an inclination angle with respect to the surface of the ceramic layer of the first vertical division, and the ceramic layer of the second vertical division. The inclination angle with respect to the surface may be different.

Moreover, the thermal barrier coating forming method according to the eighth aspect of the present invention includes a ceramic layer forming step of forming a ceramic layer containing ceramic on the surface of the heat-resistant alloy substrate, and the ceramic layer forming step includes: A first dense layer forming step for forming a dense layer and an intermediate in which a large number of pores having a higher density than the first dense layer are formed on the first dense layer after the first dense layer forming step A pore layer forming step for forming a pore layer; and a second dense layer forming step that is performed after the pore layer forming step and forms a second dense layer having a lower density than the intermediate pore layer on the intermediate pore layer; Have.

With this configuration, the intermediate pore layer is formed between the first dense layer and the second dense layer, so that heat input to the ceramic layer in the thickness direction is inhibited by the intermediate pore layer. The As a result, the thermal conductivity as the ceramic layer can be reduced. Furthermore, the adhesiveness with respect to a heat resistant alloy base material is securable by forming a 1st dense layer in the heat resistant alloy base material side in a ceramic layer. Furthermore, erosion resistance can be ensured by forming the second dense layer on the surface side in the ceramic layer.

Further, in the thermal barrier coating forming method according to the ninth aspect of the present invention, in the eighth aspect, a spraying method is used for the ceramic layer forming step, and the distance between the spray hole of the spray gun and the surface of the spray target is The first dense layer forming step and the second dense layer forming step may be shorter than the pore layer forming step.

Further, in the thermal barrier coating forming method according to the tenth aspect of the present invention, in the eighth aspect or the ninth aspect, the first dense layer forming step is such that the first vertical split extending in the thickness direction is dispersed in the surface direction. The first dense layer may be formed as described above, and in the second dense layer forming step, the second dense layer may be formed so that the second vertical division extending in the thickness direction is dispersed in the surface direction. .

Further, in the thermal barrier coating forming method according to the eleventh aspect of the present invention, in any one of the eighth aspect to the tenth aspect, the spray particles have a particle size of 0.1 μm or more and 1.0 μm or less. Also good.

Moreover, in the thermal barrier coating forming method according to the twelfth aspect of the present invention, in any one of the eighth aspect to the eleventh aspect, at least a part of the ceramic layer forming step uses suspension plasma spraying. Also good.

Moreover, the high temperature member according to the thirteenth aspect of the present invention includes a heat-resistant alloy base material and a ceramic layer formed on the heat-resistant alloy base material and containing ceramic, and the ceramic layer includes a first dense layer, An intermediate pore layer that is laminated on the first dense layer and has a higher density than the first dense layer and has a large number of pores, and an intermediate pore layer that is laminated on the intermediate pore layer and has a lower density than the intermediate pore layer A second dense layer.

In the thermal barrier coating according to the fourteenth aspect of the present invention, in the first aspect, the ceramic layer is divided in a longitudinal direction extending in a thickness direction in the plane direction, and the vertical split is formed on a surface of the ceramic layer. And may be inclined and extended.

According to such a configuration, the heat input in the thickness direction in the ceramic layer is hindered by the longitudinal split extending obliquely. Therefore, the thermal conductivity in the ceramic layer can be reduced by the vertical division. On the other hand, the erosion resistance can be prevented from decreasing by forming the ceramic layer so densely that the vertical split is formed.

In the thermal barrier coating according to the fifteenth aspect of the present invention, in the fourteenth aspect, the vertical inclination angle may be different between the surface side of the ceramic layer and the heat-resistant alloy substrate side.

In the thermal barrier coating according to the sixteenth aspect of the present invention, in the fourteenth aspect or the fifteenth aspect, the longitudinal split may have a distribution rate per 1 mm of 6 / mm to 12 / mm. Good.

In the thermal barrier coating according to the seventeenth aspect of the present invention, in any one of the fourteenth aspect to the sixteenth aspect, the vertical split may extend intermittently.

In the thermal barrier coating according to the eighteenth aspect of the present invention, in any one of the fourteenth aspect to the seventeenth aspect, all of the plurality of vertical divisions are directed toward the surface of the ceramic layer. You may incline toward the one side of a surface direction.

With such a configuration, heat input in the thickness direction is inhibited over a wide area in the surface direction of the ceramic layer. As a result, the thermal conductivity in the ceramic layer can be reduced over a wide range.

In the thermal barrier coating according to the nineteenth aspect of the present invention, in any one of the fourteenth aspect to the eighteenth aspect, the vertical inclination angle is 45 ° or more with respect to the surface of the ceramic layer. It may be an angle of 80 ° or less.

By adopting such a configuration, the effect of inhibiting heat input in the thickness direction due to vertical splitting is increased by reducing the tilt angle. As a result, the thermal conductivity in the ceramic layer can be greatly reduced. Moreover, it can suppress that it becomes difficult for a thermal spray particle to adhere to the surface at the time of forming a ceramic layer by making the vertical inclination angle into 45 degrees or more. Therefore, it is possible to suppress a decrease in the manufacturing efficiency of the ceramic layer.

The thermal barrier coating forming method according to the twentieth aspect of the present invention is the suspension according to the eighth aspect, wherein the thermal spray gun is inclined with respect to the surface of the heat-resistant alloy substrate by a predetermined inclination angle to disperse the spray particles. Thermal spraying using a turbid liquid may be performed to form a ceramic layer that includes a ceramic that extends in the thickness direction on the heat-resistant alloy base material and that includes a ceramic in which longitudinal splits that are inclined by the inclination angle are dispersed in the plane direction. Good.

With such a configuration, the heat input in the thickness direction in the ceramic layer is hindered by the longitudinal split extending obliquely. Therefore, the thermal conductivity in the ceramic layer can be reduced by the vertical division. On the other hand, the erosion resistance can be prevented from decreasing by forming the ceramic layer so densely that the vertical split is formed. In addition, since the ceramic layer is formed by suspension plasma spraying, the particle size of the spray particles forming the ceramic layer is reduced. As a result, the ceramic layer can have a very dense structure. Thereby, the adhesiveness of the ceramic layer after formation can also be improved.

In the thermal barrier coating forming method according to the twenty-first aspect of the present invention, in the twentieth aspect, the thermal spraying may be suspension plasma thermal spraying.

In the thermal barrier coating forming method according to the twenty-second aspect of the present invention, in the twentieth aspect or the twenty-first aspect, the particle size of the sprayed particles may be 0.1 μm or more and 1.0 μm or less.

The high-temperature member according to the twenty-third aspect of the present invention is the heat-resistant alloy substrate according to the thirteenth aspect, formed on the heat-resistant alloy substrate, and the vertical splits extending in the thickness direction are dispersed in the surface direction. A ceramic layer including ceramics, and the longitudinal split may extend at an angle with respect to a surface of the ceramic layer.

According to the above thermal barrier coating formation method, thermal barrier coating, and high temperature member, it is possible to enhance the thermal barrier effect while suppressing a decrease in erosion resistance.

1 is a schematic configuration diagram of a gas turbine according to an embodiment of the present invention. It is a schematic structure perspective view of a moving blade concerning an embodiment of the present invention. It is a principal part cross-sectional enlarged view of the moving blade explaining the thermal barrier coating which concerns on embodiment of this invention. It is process drawing explaining the process of the thermal barrier coating formation method in 1st embodiment of this invention. It is the figure which calculated | required the relationship between the thermal conductivity and the porosity in the topcoat layer in embodiment of this invention by simulation. It is the figure which calculated | required the relationship between the thermal conductivity in the topcoat layer in which the vertical division in embodiment of this invention was formed, and the inclination angle of vertical division by simulation. It is a principal part cross-sectional enlarged view of the moving blade explaining the thermal barrier coating which concerns on the modification of this invention. It is a principal part cross-sectional enlarged view of the moving blade explaining the thermal barrier coating which concerns on the modification of this invention.

Hereinafter, embodiments of the present invention will be described with reference to FIGS.
As shown in FIG. 1, the gas turbine 1 of the present embodiment includes a compressor 2, a combustor 3, a turbine body 4, and a rotor 5. The compressor 2 takes in a large amount of air and compresses it. The combustor 3 mixes fuel with the compressed air A compressed by the compressor 2 and burns it.

The turbine body 4 converts the thermal energy of the combustion gas G introduced from the combustor 3 into rotational energy. The turbine body 4 generates power by converting the thermal energy of the combustion gas G into mechanical rotational energy by blowing the combustion gas G onto the rotor blades 7 provided in the rotor 5. The turbine body 4 is provided with a plurality of stationary blades 8 in a casing 6 of the turbine body 4 in addition to the plurality of rotor blades 7 on the rotor 5 side. In the turbine body 4, the moving blades 7 and the stationary blades 8 are alternately arranged in the axial direction of the rotor 5. The rotor 5 transmits a part of the rotating power of the turbine body 4 to the compressor 2 to rotate the compressor 2.

Hereinafter, in this embodiment, the moving blade 7 of the turbine body 4 will be described as an example of the high temperature member of the present invention.
As illustrated in FIG. 2, the moving blade 7 includes a moving blade body 70 and a thermal barrier coating 100. The rotor blade body 70 is a heat-resistant alloy base material formed of a well-known heat-resistant alloy material such as a Ni-based alloy, for example. The rotor blade main body 70 of the present embodiment includes a blade main body portion 71, a platform portion 72, a blade root portion 73, and a shroud portion 74.

The wing body 71 has a wing shape in cross section. The blade body 71 is disposed in the flow path of the combustion gas G in the casing 6 of the turbine body 4. The platform portion 72 is provided at the proximal end of the wing body portion 71. The platform portion 72 defines a flow path for the combustion gas G on the proximal end side of the blade body portion 71. The blade root portion 73 is formed to protrude from the platform portion 72 to the opposite side of the blade body portion 71. The shroud portion 74 is provided at the tip of the wing body portion 71. The shroud portion 74 defines a flow path for the combustion gas G on the tip side of the blade body portion 71.

As shown in FIG. 3, the thermal barrier coating 100 is formed on the surface of the rotor blade main body 70 which is a heat-resistant alloy substrate. Among the surfaces of the rotor blade main body 70, the thermal barrier coating 100 includes the surface of the blade main body 71, the surface of the platform 72 connected to the blade main body 71, and the blade main body 71 of the shroud 74. It is formed so as to cover the surface on the connected side. The thermal barrier coating 100 of the present embodiment is formed by suspension plasma spraying described later. The thermal barrier coating 100 of this embodiment includes a bond coat layer 110 and a top coat layer (ceramic layer) 120.

The bond coat layer 110 is directly formed on the surface of the rotor blade body 70. The bond coat layer 110 suppresses the top coat layer 120 from peeling from the rotor blade body 70. The bond coat layer 110 is a metal bonding layer having excellent corrosion resistance and oxidation resistance. The bond coat layer 110 is formed, for example, by spraying a metal spray powder of MCrAlY alloy on the surface of the rotor blade body 70 as a spraying material. Here, “M” in the MCrAlY alloy constituting the bond coat layer 110 represents a metal element. The metal element “M” is made of, for example, a single metal element such as Ni or Co, or a combination of two or more of these.

The top coat layer 120 is formed on the rotor blade main body 70 via the bond coat layer 110. The topcoat layer 120 has a layer containing ceramic in which the longitudinal divisions C extending in the thickness direction are dispersed in the plane direction. Here, the surface direction is a direction along the surface of the topcoat layer 120. The topcoat layer 120 of this embodiment is formed with a thickness of 0.3 mm or more and 1.5 mm or less. The topcoat layer 120 has a first dense layer 121, an intermediate pore layer 122, and a second dense layer 123.

The first dense layer 121 is directly laminated on the bond coat layer 110. In the first dense layer 121, the first vertical division C1 is dispersed as the vertical division C in the surface direction in which the surface spreads. Therefore, in the first dense layer 121, a plurality of the first vertical divisions C1 are formed apart in the surface direction. The first dense layer 121 of the present embodiment is, for example, a dense DVC (Dense Vertical Crack) coating in which the first vertical divisions C1 are dispersed in the surface direction. The first dense layer 121 is formed on the most heat-resistant alloy substrate side in the top coat layer 120. The thermal spray material used when forming the first dense layer 121 is, for example, yttria-stabilized zirconia (YSZ) or ytterbia stable (ZrO ₂ ) partially stabilized with ytterbium oxide (Yb ₂ O ₃ ). Zirconia fluoride (YbSZ) is used.

The first vertical split C1 extends with a predetermined inclination angle α with respect to the surface of the topcoat layer 120. Specifically, the first vertical split C1 extends in the extending direction of an imaginary straight line connecting the base end that is the surface side of the heat-resistant alloy base material in the thickness direction and the front end that is the surface side of the topcoat layer 120. The direction is assumed. In the first vertical split C1, the extending direction is inclined with respect to the surface direction in which the surface of the top coat layer 120 is spread. Therefore, the first vertical split C 1 extends toward the one side in the surface direction with respect to the base end as it goes from the base end toward the surface of the top coat layer 120. The inclination angle α in the present embodiment is an angle in the extending direction with respect to the surface direction. In the present embodiment, the plurality of first vertical divisions C1 are all inclined toward the same direction. That is, all of the plurality of first vertical divisions C 1 are inclined toward one side in the surface direction as they go to the surface of the top coat layer 120. In addition, the first vertical division C1 is inclined over the entire region in the thickness direction as well as a part of the proximal end side and the distal end side.

The inclination angle α in the present embodiment is preferably an angle of 45 ° or more and 80 ° or less with respect to the surface of the topcoat layer 120. The inclination angle α is more preferably an angle of 50 ° or more and 70 ° or less with respect to the surface of the top coat layer 120. The inclination angle α is particularly preferably an angle of 55 ° to 65 ° with respect to the surface of the topcoat layer 120.

In the first dense layer 121, the distribution ratio of the first vertical division C1 per 1 mm is preferably 6 / mm or more and 12 / mm or less. In the first dense layer 121, it is more preferable that the distribution ratio of the first vertical division C1 per 1 mm is 8 pieces / mm or more and 10 pieces / mm or less.

The porosity of the first dense layer 121 is preferably in the range of 10% or less and 5% or more. In addition, the porosity in this embodiment is not only the occupation rate of only the pores P per unit volume, but also the occupation rate of the vertical split C and the pores P combined.

The intermediate pore layer 122 is laminated on the first dense layer 121. The intermediate pore layer 122 has a higher density than the first dense layer 121, and a large number of pores P are formed. Therefore, the intermediate pore layer 122 is a porous film formed with a larger porosity than the first dense layer 121, and has almost no vertical division C inside. The intermediate pore layer 122 of the present embodiment is formed with the same thickness as the first dense layer 121. The intermediate pore layer 122 of this embodiment is formed of the same thermal spray material as the first dense layer 121.

The porosity of the intermediate pore layer 122 of the present embodiment is preferably 10% or more and 20% or less. The porosity of the intermediate pore layer 122 is more preferably 12% or more and 18% or less. The porosity of the intermediate pore layer 122 is particularly preferably 14% or more and 16% or less.

The porosity is continuously changing at the first boundary, which is the boundary between the intermediate pore layer 122 and the first dense layer 121. Therefore, the porosity is formed so that the porosity gradually increases from the vicinity of the center in the thickness direction of the first dense layer 121 toward the vicinity of the center in the thickness direction of the intermediate pore layer 122.

The second dense layer 123 is directly laminated on the intermediate pore layer 122. In the second dense layer 123, the second vertical division C 2 is dispersed in the plane direction as the vertical division C. Therefore, in the second dense layer 123, a plurality of the second vertical divisions C2 are formed apart in the surface direction. The second dense layer 123 has a higher density than the intermediate pore layer 122. The second dense layer 123 is formed on the most surface side in the top coat layer 120. Therefore, the surface of the second dense layer 123 is the surface of the topcoat layer 120. The second dense layer 123 of the present embodiment is, for example, a dense DVC coating in which the second vertical divisions C2 are dispersed in the surface direction. The second dense layer 123 of this embodiment is a film having the same structure as the first dense layer 121. Therefore, the thermal spray material used when forming the second dense layer 123 is the same thermal spray material as the first dense layer 121.

The second vertical division C2 extends at an inclination angle α with respect to the surface of the topcoat layer 120, similarly to the first vertical division C1. Specifically, the second vertical split C2 extends in the extending direction of an imaginary straight line connecting the base end on the surface side of the heat-resistant alloy substrate in the thickness direction and the tip end on the surface side of the topcoat layer 120. The direction. In the second vertical split C2, the extending direction is inclined with respect to the surface direction in which the surface of the top coat layer 120 is spread. Therefore, like the first vertical split C1, the second vertical split C2 extends toward one side in the surface direction with respect to the base end as it goes from the base end to the surface of the topcoat layer 120. The second vertical division C2 of the present embodiment is inclined at the same angle in the same direction as the first vertical division C1. The plurality of second vertical divisions C2 are all inclined in the same direction. That is, all of the plurality of second vertical divisions C 2 are inclined toward one side in the surface direction as they go toward the surface of the top coat layer 120. In addition, the second vertical division C2 is inclined over the entire region in the thickness direction, as well as part of the proximal end side and the distal end side.

In the second dense layer 123, it is preferable that the distribution ratio of the second longitudinal division C2 per 1 mm is 6 / mm or more and 12 / mm or less. In the second dense layer 123, it is more preferable that the distribution ratio of the second longitudinal division C2 per 1 mm is 8 / mm or more and 10 / mm or less. The porosity of the second dense layer 123 is preferably within the range of 10% or less and 5% or more. In the second dense layer 123, the distribution ratio of the second vertical division C2 per mm is preferably the same as the distribution ratio of the first vertical division C1 of the first dense layer 121. The porosity of the second dense layer 123 is preferably the same as the porosity of the first dense layer 121.

The porosity is continuously changing at the second boundary, which is the boundary between the intermediate pore layer 122 and the second dense layer 123. Therefore, the porosity is formed so that the porosity gradually decreases from the vicinity of the center in the thickness direction of the intermediate pore layer 122 toward the vicinity of the center in the thickness direction of the second dense layer 123.

Next, manufacturing method S1 of a high temperature member will be described. Manufacturing method S1 of the high temperature member of this embodiment is a manufacturing method of the moving blade 7 which manufactures the moving blade 7 mentioned above as a high temperature member. As shown in FIG. 4, the high-temperature member manufacturing method S 1 of the present embodiment includes a rotor blade body preparation step S 10 and a thermal barrier coating formation step S 20.

In the blade main body preparation step S10, a heat-resistant alloy base material is prepared as the blade main body 70 in advance. In the rotor blade main body preparation step S10 of the present embodiment, the material is prepared by being formed into the shape of a target high-temperature member (for example, the rotor blade main body 70 in the present embodiment).

In the thermal barrier coating forming step S20, the thermal barrier coating 100 is formed on the surface of the rotor blade main body 70 prepared in the rotor blade main body preparing step S10 by the thermal barrier coating forming method S100. In the thermal barrier coating formation step S 20 of the present embodiment, the bond coat layer 110 and the top coat layer 120 are formed on the surface of the rotor blade main body 70. Thermal barrier coating formation process S20 of this embodiment is implemented by the following thermal barrier coating formation method S100.

In the thermal barrier coating forming method S100, the thermal barrier coating 100 is formed on the rotor blade main body 70. The thermal barrier coating forming method S100 of the present embodiment includes a bond coat layer forming step S110, a top coat layer forming step (ceramic layer forming step) S120, and an adjusting step S130.

In the bond coat layer forming step S110, the bond coat layer 110 is formed on the surface of the rotor blade body 70. The bond coat layer forming step S110 is performed after the rotor blade main body preparing step S10. In the bond coat layer forming step S 110, for example, the spray particles of the MCrAlY alloy are sprayed on the surface of the rotor blade main body 70 with a spray gun. In the bond coat layer forming step S 110, the spray gun is moved with the spray holes of the spray particles perpendicular to the surface of the rotor blade body 70. The bond coat layer forming step S110 of the present embodiment forms the bond coat layer 110 by performing high-speed flame spraying (HVOF: High Velocity Oxygen Fuel) or low-pressure plasma spraying (LPPS: Low Pressure Plasma Spraying) with a spray gun. .

In the top coat layer forming step S120, the top coat layer 120 containing ceramic is formed on the surface of the rotor blade body 70. The top coat layer forming step S120 is performed after the bond coat layer forming step S110. In the top coat layer forming step S120, the top coat layer 120 is laminated on the bond coat layer 110 formed in the bond coat layer forming step S110. In the top coat layer forming step S120, a thermal spraying method is used. Accordingly, in the top coat layer forming step S120 of the present embodiment, the top coat layer 120 is formed by spraying the spray particles on the surface of the bond coat layer 110 formed on the rotor blade main body 70. The topcoat layer forming step S120 includes a first dense layer forming step S121, a pore layer forming step S122, and a second dense layer forming step S123.

The first dense layer forming step S121 is performed after the bond coat layer forming step S110. In the first dense layer forming step S 121, the first dense layer 121 is formed on the bond coat layer 110. In the first dense layer forming step S121, suspension plasma spraying is performed to form the first dense layer 121. In the first dense layer forming step S121, suspension plasma spraying is performed by inclining the thermal spray gun with respect to the surface of the rotor blade main body 70 by a predetermined inclination angle α. Suspension plasma spraying is a spraying method in which a suspension in which fine spray particles are dispersed is supplied into a plasma jet to form a coating. Note that the distance between the spray hole of the spray gun and the surface of the rotor blade main body 70 to be sprayed is shorter in the first dense layer forming step S121 than in the pore layer forming step S122.

The fine spray particles preferably have a particle size of 0.1 μm or more and 1.0 μm or less. Examples of the carrier used for the suspension include water and ethanol. In suspension plasma spraying, a suspension gun spraying system may use an axial flow internal supply spray gun or an external supply spray gun.

The pore layer forming step S122 is performed after the first dense layer forming step S121. In the pore layer forming step S 122, the intermediate pore layer 122 is formed on the first dense layer 121. In the pore layer forming step S122, suspension plasma spraying is performed to form the intermediate pore layer 122. In the pore layer forming step S122, the thermal spray gun is separated from the moving blade main body 70 to spray the thermal spray particles more than in the first dense layer forming step S121. In the pore layer forming step S122, first, spraying is performed while moving the spray gun so as to gradually move away from the spraying distance in the first dense layer forming step S121. Thereafter, when the intermediate pore layer 122 is formed to about half the desired film thickness of the intermediate pore layer 122, the spray distance is gradually brought closer to the spray distance in the second dense layer forming step S123. Finally, when the intermediate pore layer 122 having a desired thickness is formed, the spray gun is moved so that the spray distance matches the spray distance in the second dense layer forming step S123.

The second dense layer forming step S123 is performed after the pore layer forming step S122. In the second dense layer forming step S123, the second dense layer 123 is formed on the intermediate pore layer 122. In the second dense layer forming step S123, suspension plasma spraying is performed to form the second dense layer 123. In the second dense layer forming step S123, the thermal spray gun is brought closer to the moving blade body 70 than in the pore layer forming step S122 to spray the thermal spray particles. The second dense layer forming step S123 of the present embodiment is performed under the same conditions as the first dense layer forming step S121. Therefore, in the second dense layer forming step S123, the thermal spray gun is inclined by a predetermined inclination angle α with respect to the surface of the rotor blade body 70 and sprayed by suspension plasma spraying. The distance between the spray hole of the spray gun and the surface of the moving blade main body 70 that is the object of spraying is shorter in the second dense layer forming step S123 than in the pore layer forming step S122.

The adjusting step S130 is performed after the second dense layer forming step S123. The adjustment step S130 adjusts the surface state of the thermal barrier coating 100. Specifically, in the adjustment step S130, the surface of the top coat layer 120 is slightly shaved to adjust the film thickness of the thermal barrier coating 100, or to make the surface smoother. By this adjustment process S130, the heat conductivity to the moving blade 7 can be reduced, for example. In the adjusting step S130 of this embodiment, the surface of the second dense layer 123 is shaved by several μm to smooth the surface of the topcoat layer 120 and adjust the film thickness.

According to the thermal barrier coating 100, the thermal barrier coating formation method S100, and the rotor blade 7 as described above, the intermediate pore layer 122 is formed between the first dense layer 121 and the second dense layer 123. Heat input to the top coat layer 120 in the thickness direction is inhibited by the intermediate pore layer 122. As a result, the thermal conductivity as the top coat layer 120 can be further reduced. By forming the first dense layer 121 on the side of the top coat layer 120 that is in close contact with the bond coat layer 110 on the rotor blade main body 70 side, adhesion to the bond coat layer 110 can be ensured. Furthermore, erosion resistance can be ensured by forming the second dense layer 123 on the surface side in the top coat layer 120. Accordingly, it is possible to enhance the heat shielding effect while suppressing a decrease in erosion resistance in the heat shielding coating 100.

Specifically, the point that the thermal conductivity is lowered due to the presence of the intermediate pore layer 122 will be described with reference to FIG. FIG. 5 is a diagram in which the relationship between the thermal conductivity and the porosity in the topcoat layer 120 is obtained by simulation. As shown in FIG. 5, in the topcoat layer 120, the thermal conductivity in the topcoat layer 120 decreases as the porosity increases. More specifically, when the porosity increases from 0% to 15%, the thermal conductivity decreases by about 10%. Therefore, it can be seen that the thermal conductivity of the topcoat layer 120 can be lowered by forming the intermediate porosity layer 122 having a high porosity between the first dense layer 121 and the second dense layer 123.

In addition, by setting the porosity in the intermediate pore layer 122 to 10% or more and 20% or less, the effect of inhibiting heat input in the thickness direction by the first vertical division C1 and the second vertical division C2 is increased. As a result, the thermal conductivity in the topcoat layer 120 can be greatly reduced without greatly reducing the erosion resistance in the intermediate pore layer 122.

Moreover, the vertical division C formed diagonally in the topcoat layer 120 is formed like the first vertical division C1 and the second vertical division C2. Therefore, the heat input in the thickness direction in the first dense layer 121 is hindered by the first vertical split C1 extending obliquely. Similarly, the heat input in the thickness direction in the second dense layer 123 is hindered by the second vertical split C2 extending obliquely. Therefore, the thermal conductivity in the topcoat layer 120 can be reduced by the first vertical division C1 and the second vertical division C2. On the other hand, the second dense layer 123 is formed on the surface side of the top coat layer 120. By forming the second dense layer 123 as densely as the vertical split C is formed, it is possible to suppress a decrease in erosion resistance. As a result, the heat shielding effect can be enhanced while suppressing a decrease in the erosion resistance on the surface side of the thermal barrier coating 100.

Specifically, the point that the thermal conductivity is lowered by inclining the vertical split C will be described with reference to FIG. FIG. 6 is a diagram in which the relationship between the thermal conductivity in the top coat layer 120 in which the vertical division C is formed and the inclination angle α of the vertical division C is obtained by simulation. As shown in FIG. 6, in the top coat layer 120, the smaller the inclination angle α of the longitudinal split C, the smaller the thermal conductivity in the top coat layer 120. More specifically, the thermal conductivity is 25% or more when the inclination angle α of the vertical division C is 60 ° as compared to the state where the vertical division C is not inclined (when the inclination angle α is 90 °). descend. Therefore, it can be seen that the thermal conductivity in the topcoat layer 120 can be lowered by making the vertical division C oblique.

Further, since the topcoat layer 120 is formed by suspension plasma spraying, the particle size of the sprayed particles forming the topcoat layer 120 is smaller than that of atmospheric plasma spraying (APS). As a result, the first dense layer 121 and the second dense layer 123 can have a very dense structure. Therefore, the adhesion between the first dense layer 121 and the bond coat layer 110 and the adhesion between the layers in the top coat layer 120 can be improved.

Further, since all of the first vertical division C1 and the second vertical division C2 are inclined in the same direction, the first dense layer 121 and the second dense layer 123 extend in the thickness direction over a wide area in the surface direction. Heat input is hindered. As a result, the thermal conductivity in the topcoat layer 120 can be reduced over a wide range.

Further, the inclination angle α of the first vertical division C1 and the second vertical division C2 is set to 45 ° or more and 80 ° or less. By decreasing the inclination angle α, the effect of inhibiting heat input in the thickness direction by the first vertical division C1 and the second vertical division C2 is increased. As a result, the thermal conductivity in the top coat layer 120 can be significantly reduced. In addition, by setting the inclination angle α of the first vertical division C1 and the second vertical division C2 to 45 degrees or more, it becomes difficult for the spray particles to adhere to the surface when the first dense layer 121 and the second dense layer 123 are formed. Can be suppressed. Therefore, it is possible to further suppress a decrease in manufacturing efficiency of the topcoat layer 120.

(Other variations of the embodiment)
Although the embodiments of the present invention have been described in detail with reference to the drawings, the configurations and combinations of the embodiments in the embodiments are examples, and the addition and omission of configurations are within the scope not departing from the gist of the present invention. , Substitutions, and other changes are possible. Further, the present invention is not limited by the embodiments, and is limited only by the scope of the claims.

In addition, in the said embodiment, although the 1st vertical division C1 and the 2nd vertical division C2 have comprised the structure, the topcoat layer 120 is not limited to such a structure. For example, as shown in FIG. 7, the top coat layer 120 A of the thermal barrier coating 100 A having a structure having a vertical division C (non-inclined vertical division) extending perpendicular to the surface direction may be formed. . Therefore, the first vertical division C1 of the first dense layer 121A and the second vertical division C2 of the second dense layer 123A extend in a direction perpendicular to the surface of the topcoat layer 120A.

In the above embodiment, the top coat layer 120 has a multilayer structure in which the intermediate pore layer 122 is formed between the first dense layer 121 and the second dense layer 123. However, the topcoat layer 120 is not limited to such a structure. For example, as shown in FIG. 8, the top coat layer 120 A of the thermal barrier coating 100 A may be formed as a single-layer structure having an inclined vertical division C.

Further, in the thermal barrier coating forming method S100 of the present embodiment, the bond coat layer forming step S110 may not be performed. For example, the bond coat layer 110 may be formed by another method, and the bond coat layer 110 itself may not be formed. When the bond coat layer 110 is not formed, the ceramic layer may be formed directly on the surface of the rotor blade main body 70.

Further, the high temperature member is not limited to the rotor blade 7 and may be any member that is exposed to high temperature. For example, the present invention may be applied to a member such as a nozzle or a cylinder constituting the stationary blade 8 of the gas turbine 1 or the combustor 3 as the high temperature member. Further, the high temperature member may be a member exposed to a high temperature other than the gas turbine 1. For example, the high temperature member may be a member exposed to a high temperature environment in a gas engine.

Further, the intermediate pore layer 122 is not limited to a structure in which the vertical split C is not completely formed and only the pores P are formed. As long as the porosity of the intermediate pore layer 122 is sufficiently large, the vertical split C may be formed to some extent. Similarly, the first dense layer 121 and the second dense layer 123 may have some pores P as long as the longitudinal split C is formed.

Moreover, the extending direction of the vertical divisions such as the first vertical division C1 and the second vertical division C2 is not limited to the extending direction of the virtual straight line connecting the base end and the distal end as described above. Absent. The extending direction of the vertical division may be the direction in which the approximate straight line extends by obtaining an approximate straight line by image analysis or the like from the vertically bent vertical division.

The first vertical division C1 and the second vertical division C2 only need to be inclined, and are not limited to being inclined in the same direction over the entire area. The inclination angle α of the longitudinal split C may be different between the surface side of the ceramic layer and the rotor blade body 70 side. That is, for example, if the vertical split is inclined in the same direction, it may be inclined at a different angle in the middle of the extending direction. Therefore, in the first vertical division C1 and the second vertical division C2, for example, the inclination angle α in the region near the surface of the topcoat layer 120 is larger than the inclination angle α in the region near the surface of the rotor blade body 70. It may be formed small.

In the present embodiment, the first dense layer 121 has the first vertical division C1 and the second dense layer 123 has the second vertical division C2 having the same inclination angle α. However, the first dense layer 121 and the second dense layer 121 have the same inclination angle α. The dense layer 123 is not limited to such a structure. Therefore, the inclination angle α with respect to the surface of the top coat layer 120 of the first vertical division C1 may be different from the inclination angle α with respect to the surface of the top coat layer 120 of the second vertical division C2. At this time, it is preferable that the inclination angle α of the first vertical division C1 is smaller than the inclination angle α of the second vertical division C2.

In the present embodiment, the distribution ratio of the vertical division C per mm of the first dense layer 121 and the second dense layer 123 is the same, but the first dense layer 121 and the second dense layer 123 have such a structure. It is not limited to. For example, the distribution ratio of the vertical division C per 1 mm of the second dense layer 123 may be made larger or smaller than the distribution ratio of the vertical division C per 1 mm of the first dense layer 121.

In the present embodiment, the porosity of the first dense layer 121 and the second dense layer 123 is the same, but the first dense layer 121 and the second dense layer 123 are not limited to such a structure. . For example, the porosity of the first dense layer 121 and the second dense layer 123 may be different from each other as long as it is lower than the porosity of the intermediate pore layer 122.

Further, in the vertical division C of the present embodiment, an interval is provided in the middle pore layer 122 in the vicinity of the middle in the thickness direction in one top coat layer 120 as in the first vertical division C1 and the second vertical division C2. It is formed as follows. Thus, the longitudinal split C is not limited to a structure in which the ceramic layer is continuous from the surface facing the rotor blade main body 70 side to the surface. Therefore, the longitudinal split C may extend intermittently in the thickness direction within one ceramic layer. Therefore, the first vertical division C1 and the second vertical division C2 are not limited to the structure extending continuously as in this embodiment. For example, the first vertical divisions C1 may be formed in the first dense layer 121 at intervals in the thickness direction. Similarly, the second vertical divisions C 2 may be formed in the second dense layer 123 with an interval in the thickness direction.

Further, in the pore layer forming step S122 of the present embodiment, the spray gun is moved so as to gradually change (remove) the spray distance, but it is not limited to moving the spray gun in this way. . For example, in the pore layer forming step S122, the spray gun may be moved so as to change rapidly from the spraying distance in the first dense layer forming step S121 to the target spraying distance in the pore layer forming step S122.

Moreover, the thermal spraying conditions mentioned in each process are only examples, and are not limited. The thermal spraying conditions may be appropriately set according to the apparatus used, the type of the thermal spraying particles to be used, and the like.

The present invention can be applied to a thermal barrier coating forming method, a thermal barrier coating, and a high-temperature member, and can enhance a thermal barrier effect while suppressing a decrease in erosion resistance.

DESCRIPTION OF SYMBOLS 1 ... Gas turbine 2 ... Compressor 3 ... Combustor 4 ... Turbine body 5 ... Rotor 6 ... Casing 7 ... Rotor blade 70 ... Rotor blade body 71 ... Blade body portion 72 ... Platform portion 73 ... Blade root portion 74 ... Shroud portion 8 ... Stator blade A ... Compressed air G ... Combustion gas 100 ... Thermal barrier coating 110 ... Bond coat layer 120 ... Top coat layer 121 ... First dense layer C1 ... First vertical split α ... Inclination angle 122 ... Middle pore layer P ... Pore 123 ... second dense layer C2 ... second vertical split S1 ... high temperature member manufacturing method S10 ... blade body preparation step S20 ... thermal barrier coating formation step S100 ... thermal barrier coating formation method S110 ... bond coat layer formation step S120 ... topcoat Layer formation step S121 ... First dense layer formation step S122 ... Porous layer formation step S 23 ... second dense layer forming step S130 ... adjusting step C ... vertical split

Claims

Formed on a heat-resistant alloy substrate, comprising a ceramic layer containing ceramic,
The ceramic layer is
A first dense layer;
An intermediate pore layer that is laminated on the first dense layer and has a larger number of pores than the first dense layer;
A second dense layer laminated on the intermediate pore layer and having a lower density than the intermediate pore layer;
Thermal barrier coating.
The porosity continuously changes at the first boundary portion, which is the boundary portion between the intermediate pore layer and the first dense layer, and at the second boundary portion, which is the boundary portion between the intermediate pore layer and the second dense layer. The thermal barrier coating according to claim 1.
The thermal barrier coating according to claim 1 or 2, wherein the porosity of the intermediate pore layer is 10% or more and 20% or less.
The thermal barrier coating according to any one of claims 1 to 3, wherein the porosity of the first dense layer and the second dense layer is 10% or less and 5% or more.
In the first dense layer, the first vertical split extending in the thickness direction is dispersed in the plane direction,
The thermal barrier coating according to any one of claims 1 to 4, wherein the second dense layer has second longitudinal divisions extending in a thickness direction dispersed in a plane direction.
The thermal barrier coating according to claim 5, wherein the first vertical split and the second vertical split are inclined with respect to the surface of the ceramic layer.
The thermal barrier coating according to claim 5 or 6, wherein an inclination angle with respect to a surface of the ceramic layer of the first vertical division is different from an inclination angle with respect to the surface of the ceramic layer of the second vertical division.
Including a ceramic layer forming step of forming a ceramic layer containing ceramic on the surface of the heat-resistant alloy substrate;
The ceramic layer forming step includes
A first dense layer forming step of forming a first dense layer;
A pore layer forming step, which is performed after the first dense layer forming step, and forms an intermediate pore layer in which a large number of pores having a larger density than the first dense layer are formed on the first dense layer;
A thermal barrier coating forming method comprising: a second dense layer forming step, which is performed after the pore layer forming step and forming a second dense layer having a density lower than that of the intermediate pore layer on the intermediate pore layer.
Thermal spraying is used for the ceramic layer forming step,
The thermal barrier coating formation according to claim 8, wherein the distance between the spray hole of the thermal spray gun and the surface of the thermal spray target is shorter in the first dense layer forming step and the second dense layer forming step than in the pore layer forming step. Method.
In the first dense layer forming step, the first dense layer is formed such that the first vertical split extending in the thickness direction is dispersed in the surface direction,
10. The thermal barrier coating forming method according to claim 8, wherein in the second dense layer forming step, the second dense layer is formed such that the second vertical division extending in the thickness direction is dispersed in the surface direction. .
The thermal barrier coating formation method according to any one of claims 8 to 10, wherein the sprayed particles have a particle size of 0.1 µm or more and 1.0 µm or less.
The thermal barrier coating forming method according to any one of claims 8 to 11, wherein at least a part of the ceramic layer forming step uses suspension plasma spraying.
A heat-resistant alloy substrate;
A ceramic layer formed on the heat-resistant alloy substrate and including ceramic;
The ceramic layer is
A first dense layer;
An intermediate pore layer that is laminated on the first dense layer and has a larger number of pores than the first dense layer;
A high temperature member having a second dense layer laminated on the intermediate pore layer and having a density lower than that of the intermediate pore layer.
In the ceramic layer, longitudinal splits extending in the thickness direction are dispersed in the plane direction,
The thermal barrier coating according to claim 1, wherein the vertical split extends at an angle with respect to the surface of the ceramic layer.
The thermal barrier coating according to claim 14, wherein an inclination angle of the vertical division is different between the surface side of the ceramic layer and the heat-resistant alloy base material side.
The thermal barrier coating according to claim 14 or 15, wherein the vertical division has a distribution rate per mm of 6 / mm to 12 / mm.
The thermal barrier coating according to any one of claims 14 to 16, wherein the longitudinal split extends intermittently.
The thermal barrier coating according to any one of claims 14 to 17, wherein all of the plurality of vertical divisions are inclined toward one side in the surface direction as they go toward the surface of the ceramic layer. .
The thermal barrier coating according to any one of claims 14 to 18, wherein the vertical inclination angle is an angle of 45 ° to 80 ° with respect to the surface of the ceramic layer.
The thermal spray gun is inclined with respect to the surface of the heat-resistant alloy substrate by a predetermined inclination angle, sprayed using a suspension in which the spray particles are dispersed, and extends in the thickness direction on the heat-resistant alloy substrate. The method for forming a thermal barrier coating according to claim 8, wherein a ceramic layer including ceramic in which longitudinal divisions inclined at an inclination angle are dispersed in a plane direction is formed.
The thermal barrier coating formation method according to claim 20, wherein the thermal spraying is suspension plasma thermal spraying.
The method for forming a thermal barrier coating according to claim 20 or 21, wherein a particle diameter of the sprayed particles is 0.1 µm or more and 1.0 µm or less.
A heat-resistant alloy substrate;
A ceramic layer that is formed on the heat-resistant alloy substrate and includes a ceramic in which longitudinal splits extending in the thickness direction are dispersed in the plane direction;
The high-temperature member according to claim 13, wherein the vertical split extends obliquely with respect to the surface of the ceramic layer.