Method for applying heat-shielding coating and method for manufacturing heat-resistant material

Abstract

To suppress the cost of a thermal barrier coating in a heat resistant member.SOLUTION: A method for constructing a thermal barrier coating comprises the step of forming a topcoat layer on a bond coat layer formed on the heat resistant alloy base material of an object. The step of forming the topcoat layer comprises forming the topcoat layer by spraying a suspension including ceramic powder by atmospheric pressure plasma spray while cooling a part of plasma flame by supplying water around the plasma flame at a supply rate of 25 ml / min. or more and 100 ml / min. or less as a cooling fluid.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to a method for applying a thermal barrier coating and a heat-resistant member.

Background Art

[0002] It is known that heat-resistant members exposed to high-temperature combustion gas, such as combustor panels and turbine blades in aircraft engines, and turbine blades and split rings in industrial gas turbines, are provided with a Thermal Barrier Coating (TBC). Such a thermal barrier coating includes a bond coat layer formed on a heat-resistant alloy substrate, and a top coat layer as a thermal barrier layer formed on the bond coat layer. The bond coat layer is formed on a heat-resistant alloy substrate, for example, by thermal spraying (see, for example, Patent Document 1). In addition, since it is difficult to ensure desired thermal cycle durability for the top coat layer by, for example, atmospheric pressure plasma spraying (APS), in order to ensure thermal cycle durability, the top coat layer may be formed by electron beam physical vapor deposition (EB-PVD) so that the layer contains cracks called vertical cracks extending in the thickness direction of the top coat layer (see, for example, Patent Document 2).

Prior Art Literature

Patent Literature

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problem to be Solved by the Invention

[0004] The initial cost of equipment for electron beam physical deposition is more than 10 times higher than that of thermal spraying equipment. Furthermore, the running costs for forming layers by electron beam physical deposition are about 10 times higher than those for forming layers by thermal spraying, etc. Moreover, the layer formation rate by electron beam physical deposition is low, only a fraction of that of thermal spraying, etc. Therefore, there is a need for a method to form a topcoat layer at a lower cost while ensuring performance such as heat shielding and thermal cycle durability as a topcoat layer for heat shielding coatings.

[0005] At least one embodiment of this disclosure aims to reduce the cost of heat-shielding coatings in heat-resistant members, in view of the circumstances described above. To reduce costs, it is necessary to improve the heat-shielding properties and thermal cycle durability of the topcoat of the heat-shielding coating formed by thermal spraying or the like. [Means for solving the problem]

[0006] (1) A method for applying a heat-shielding coating according to at least one embodiment of the present disclosure is: The process includes a step of forming a top coat layer on a bond coat layer formed on a heat-resistant alloy substrate of the object, In the process of forming the topcoat layer, the topcoat layer is formed by spraying a suspension containing ceramic powder by atmospheric pressure plasma spraying while cooling a portion of the plasma flame by supplying water as a cooling fluid at a supply rate of 25 ml / min to 100 ml / min.

[0007] (2) A heat-resistant member according to at least one embodiment of the present disclosure has the top coat layer formed by the heat-shielding coating application method according to (1) above. [Effects of the Invention]

[0008] According to at least one embodiment of this disclosure, the cost of heat-shielding coatings on heat-resistant members can be reduced. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic diagram of a cross-section of a heat-resistant member equipped with a heat-shielding coating applied by a heat-shielding coating application method according to several embodiments. [Figure 2] This diagram shows the appearance of a combustor panel for an aircraft engine, as an example of a heat-resistant component. [Figure 3] This flowchart shows the procedure for applying a heat-shielding coating according to several embodiments. [Figure 4] This diagram illustrates the general structure of an apparatus related to a method for applying a heat-shielding coating according to several embodiments. [Figure 5] This table shows the common construction conditions for Examples 1 to 3 and the Comparative Example. [Figure 6] This table shows the test results when a flat plate-shaped component is used as the heat-resistant alloy substrate. [Figure 7] This graph shows the test results of a thermal cycle durability test using a cylindrical component. [Figure 8A] This is an SEM image of a cross-section of a test specimen in which a topcoat layer was formed under the same construction conditions as in Example 1. [Figure 8B] The area enclosed by the dashed line in Figure 8A is a grayscale image representing the crystal orientation color-coded using image processing. [Figure 8C] This graph shows the crystal grain size distribution for the region enclosed by the dashed line in Figure 8A. [Figure 9A] This is an SEM image of a cross-section of a test specimen in which the topcoat layer was formed under the same construction conditions as the comparative example. [Figure 9B] The area enclosed by the dashed line in Figure 9A is a grayscale image representing the crystal orientation color-coded using image processing. [Figure 9C] This graph shows the crystal grain size distribution for the region enclosed by the dashed line in Figure 9A. [Figure 10] This graph shows the relationship between the amount of water supplied from the cooling fluid supply unit and the deposition rate, which is the film thickness per pass of thermal spraying during the application of the topcoat layer. MODE FOR CARRYING OUT THE INVENTION

[0010] Hereinafter, several embodiments of the present disclosure will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements and the like of components described in the embodiments or shown in the drawings are not intended to limit the scope of the present disclosure, and are merely illustrative examples. For example, expressions indicating relative or absolute arrangements such as "in a certain direction", "along a certain direction", "parallel", "perpendicular", "center", "concentric" or "coaxial" not only strictly represent such an arrangement, but also represent a state of relative displacement within a tolerance or at an angle or distance that allows the same function to be obtained. For example, expressions indicating that things are in an equal state such as "identical", "equal" and "homogeneous" not only strictly represent an equal state, but also represent a state where there is a difference within a tolerance or a difference that allows the same function to be obtained. For example, expressions representing shapes such as a quadrangular shape or a cylindrical shape not only represent shapes such as a quadrangular shape or a cylindrical shape in a geometrically strict sense, but also represent shapes including uneven portions, chamfered portions and the like within a range where the same effect can be obtained. On the other hand, the expressions "comprising", "comprehending", "including", "containing" or "having" one component are not exclusive expressions that exclude the presence of other components.

[0011] (Regarding Thermal Barrier Coating 3) FIG. 1 is a schematic cross-sectional view of a heat-resistant member 1 provided with a thermal barrier coating 3 applied by a thermal barrier coating application method according to several embodiments. FIG. 2 is a view showing the external appearance of a combustor panel 1A for an aircraft engine as an example of the heat-resistant member 1. A thermal barrier coating (TBC) 3 for heat insulation of the heat-resistant member 1 is formed on the heat-resistant member 1 such as a combustor panel 1A for an aircraft engine, a turbine blade, or a turbine blade or a split ring for an industrial gas turbine. On a heat-resistant alloy base material (base metal) 5 of a heat-resistant member 1 according to some embodiments, a metal bonding layer (bond coat layer) 7 and a top coat layer 9 serving as a thermal barrier layer are formed in this order. That is, in some embodiments, the thermal barrier coating 3 includes the bond coat layer 7 and the top coat layer 9.

[0012] The heat-resistant alloy base material 5 according to some embodiments is made of, for example, a nickel-based alloy. This improves the heat resistance of the heat-resistant alloy base material 5. The bond coat layer 7 according to some embodiments is composed of MCrAlY alloy (M represents a metal element such as Ni, Co, Fe or a combination of two or more of these), or the like.

[0013] The top coat layer 9 according to some embodiments is preferably composed of a ZrO₂-based material, for example, YSZ (yttria-stabilized zirconia) which is ZrO₂ partially or fully stabilized by Y₂O₃. Further, the top coat layer 9 according to some embodiments may be composed of any one of DySZ (dysprosia-stabilized zirconia), ErSZ (erbia-stabilized zirconia), Gd₂Zr₂O₇, or Gd₂Hf₂O₇. Thereby, the thermal barrier coating 3 excellent in thermal barrier properties can be obtained.

[0014] (Flow chart) FIG. 3 is a flowchart showing procedures of a method for applying a thermal barrier coating according to some embodiments. The method for applying a thermal barrier coating according to some embodiments includes a step S10 of forming the bond coat layer 7 and a step S20 of forming the top coat layer 9.

[0015] In some embodiments, step S10 of forming the bond coat layer 7 is a step of forming the bond coat layer 7 on the heat-resistant alloy base material 5 by thermal spraying. In some embodiments, step S10 of forming the bond coat layer 7 may be, for example, a step of forming the bond coat layer on the heat-resistant alloy base material 5 by atmospheric pressure plasma spraying. In other words, in some embodiments, in step S10 of forming the bond coat layer 7, powder such as MCrAlY alloy as a thermal spray material may be thermal sprayed onto the surface of the heat-resistant alloy substrate 5 by atmospheric pressure plasma spraying.

[0016] In some embodiments, step S20 for forming the topcoat layer 9 is a step for forming the topcoat layer 9 on a bond coat layer 7 formed on a heat-resistant alloy substrate 5 of the heat-resistant member 1 which is the object to be thermal sprayed. In some embodiments, in step S20 for forming the topcoat layer 9, the topcoat layer is formed by thermal spraying a suspension containing ceramic powder by atmospheric pressure plasma spraying. That is, in some embodiments, the thermal spraying performed in step S20 for forming the topcoat layer 9 is atmospheric pressure plasma spraying (S-APS) with a suspension. In some embodiments, in step S20 for forming the topcoat layer 9, a suspension in which ceramic powder as a thermal spraying material is dispersed in a solvent is thermal sprayed onto the surface of the bond coat layer 7 by atmospheric pressure plasma spraying.

[0017] In atmospheric pressure plasma spraying using a suspension, the spray material supplied as a suspension S is sprayed onto the surface of the object to be sprayed by a plasma flame P ejected from the nozzle of the spray gun (see Figure 4, described later). In some embodiments, in step S20 for forming the topcoat layer 9, as will be described in detail later, the topcoat layer 9 is formed by spraying a suspension S containing ceramic powder by atmospheric pressure plasma spraying while cooling a portion of the plasma flame P from around the plasma flame with a cooling fluid. The conditions for thermal spraying in step S20, which forms the topcoat layer 9, will be explained later.

[0018] (Outline of the device configuration) Figure 4 is a diagram illustrating the schematic of an apparatus related to a method for applying a heat-shielding coating according to several embodiments. As shown in Figure 4, in some embodiments of the heat-shielding coating application method, the topcoat layer 9 is applied using a thermal spray gun 30 for atmospheric pressure plasma spraying, a supply unit 35 for supplying a suspension S containing powder of the thermal spray material for the topcoat layer 9, and a cooling fluid supply unit (water shroud) 40 for supplying water W as a cooling fluid from around the plasma flame P. In addition to the devices shown in Figure 4, some embodiments of the heat-shielding coating application method also include, although not shown, a thermal spray control panel, a suspension supply device, a water W supply device as a cooling fluid, etc. Note that in Figure 4, the device configuration related to the formation of the topcoat layer 9 is omitted from the illustration.

[0019] The cooling fluid supply unit 40 includes, for example, a plurality of nozzles 41 positioned downstream of the suspension S supply unit 35 in terms of the injection direction of the plasma flame P. For example, the plurality of nozzles 41 are arranged in a circumferential direction centered on a virtual central axis AX of the plasma flame P along the injection direction of the plasma flame P, so as to surround the plasma flame P. The cooling fluid supply unit 40 is configured so that water W from the plurality of nozzles 41 is injected toward the central axis AX. However, the cooling fluid supply unit 40 is not limited to the above-described configuration as long as it is configured so that water W is injected toward the central axis AX.

[0020] By injecting water W from the cooling fluid supply unit 40 toward the plasma flame P, the temperature of the plasma flame P decreases in the radially outer region (outer region Ro) centered on the central axis AX. As a result, the ceramic powder present in the outer region Ro, i.e., the raw material powder for the top coat layer 9, collides with the surface of the object to be thermal sprayed (the surface of the bond coat layer 7) without melting, and therefore does not adhere (weld) to the surface of the object to be thermal sprayed. However, in the region of the plasma flame P located radially inward from the central axis AX (inner region Ri), the plasma flame P is hardly affected by water W, and the temperature of the inner region Ri hardly decreases. Therefore, the raw material powder for the topcoat layer 9 present in the inner region Ri collides with the surface of the bond coat layer 7 in a molten state and accumulates on the surface of the bond coat layer 7.

[0021] Even when water W is not being sprayed from the cooling fluid supply unit 40 toward the plasma flame P, the temperature of the plasma flame P is lower in the radially outer region of the plasma flame P with respect to the radially inner region of the plasma flame P with respect to the central axis AX. As a result, the ceramic powder present in the radially outer region, i.e., the raw material powder for the topcoat layer 9, collides with the surface of the object to be thermal sprayed (the surface of the bond coat layer 7) without being sufficiently heated, causing the structure of the topcoat layer 9 to become coarse.

[0022] For example, in a device configuration like the one shown in Figure 4, when a suspension S is supplied from the radially outer side of the plasma flame P toward the plasma flame P, the relatively small-particle ceramic powder in the suspension S will be carried along by the plasma flame flow in the outer region Ro before reaching the inner region Ri of the plasma flame P. Furthermore, the ceramic powder particles with relatively large particle sizes in the suspension S have a relatively large inertial force that causes them to move along the radial direction around the central axis AX. As a result, they penetrate the inner region Ri of the plasma flame P and reach the outer region Ro beyond it, and become part of the plasma flame flow in the outer region Ro. Therefore, the relatively small-particle ceramic powders and the relatively large-particle ceramic powders in the suspension S will not adhere (weld) to the bond coat layer 7. In other words, in the heat-shielding coating application methods according to some embodiments, the remaining ceramic powders, excluding the relatively small-particle ceramic powders and the relatively large-particle ceramic powders in the suspension S, will accumulate on the surface of the bond coat layer 7. Furthermore, in the heat-shielding coating application methods according to some embodiments, when water W is not sprayed toward the plasma flame P as described above, it is possible to suppress the adhesion (welding) of ceramic powder to the bond coat layer 7 in the radially outer region of the plasma flame P, where heating is insufficient. As a result, the structure of the topcoat layer 9 becomes denser.

[0023] In this way, by cooling a portion of the plasma flame from around the flame with a cooling fluid while spraying a suspension containing ceramic powder by atmospheric pressure plasma spraying, the structure of the sprayed layer can be made relatively dense. However, in heat-shielding coatings, it is necessary to suppress heat transfer to the substrate by keeping the thermal conductivity low, but densification of the structure leads to an increase in thermal conductivity. For this reason, spraying a suspension containing ceramic powder by atmospheric pressure plasma spraying while cooling a portion of the plasma flame from around the plasma flame with a cooling fluid has not been performed until now from the standpoint of suppressing densification of the structure of the sprayed layer.

[0024] As a result of diligent research by the inventors, it was found that when a topcoat layer 9 is formed by spraying a suspension containing ceramic powder by atmospheric pressure plasma spraying while a portion of the plasma flame P is cooled from around the plasma flame P with a cooling fluid, the structure of the topcoat layer 9 becomes relatively dense, while the increase in thermal conductivity is kept relatively low. Furthermore, it was found that the relatively dense structure of the topcoat layer 9 significantly improves thermal cycle durability. In other words, it has been found that a construction method previously thought to be unsuitable for forming the heat-shielding layer (topcoat layer 9) in heat-shielding coating 3 is actually suitable for forming the heat-shielding layer (topcoat layer 9) in heat-shielding coating 3. According to several embodiments of the method for applying a heat-shielding coating, a topcoat layer 9 can be formed at low cost without performing electron beam physical deposition, and the thermal cycle durability of the heat-shielding coating 3 can be improved.

[0025] In some embodiments of the method for applying a heat-shielding coating, in step S20, where the top coat layer 9 is formed, water W is supplied around the plasma flame P as a cooling fluid. By using water W as the cooling fluid, the cooling fluid becomes readily available, and because its latent heat of vaporization is relatively large, it can efficiently cool the area around the plasma flame P, thus providing a good cooling effect at a low cost.

[0026] Furthermore, in the heat-shielding coating application methods according to some embodiments, as will be described later, in step S20 for forming the top coat layer 9, it is preferable to supply water W around the plasma flame P at a supply rate of 100 ml / min or less. As a result of diligent research by the inventors, it was found that in step S20, when water W is supplied around the plasma flame P at a supply rate of 100 ml / min or less, the thermal cycle durability of the heat-shielding coating 3 is significantly improved, as will be described later. Therefore, according to the application method of the heat-shielding coating as embodied in several embodiments, the thermal cycle durability of the heat-shielding coating 3 can be significantly improved.

[0027] In some embodiments of the heat-shielding coating application method, the material of the ceramic powder, i.e., the raw material powder of the top coat layer 9, may include any of yttria-stabilized zirconia, dyspurosia-stabilized zirconia, ervia-stabilized zirconia, Gd2Zr2O7, or Gd2Hf2O7. This results in a heat-shielding coating 3 with excellent heat-shielding properties.

[0028] In some embodiments of the heat-shielding coating application method, the heat-resistant alloy substrate 5 is preferably a nickel-based alloy substrate. This improves the heat resistance of the heat-resistant alloy substrate 5.

[0029] Some heat-resistant members 1 according to several embodiments have a top coat layer 9 formed by the heat-shielding coating application method described above. This makes it possible to improve the thermal cycle durability of the heat-shielding coating 3 while suppressing the manufacturing cost of the heat-resistant component 1.

[0030] (Regarding the examples) The following describes examples in which the topcoat layer 9 is formed by a heat-shielding coating application method according to several embodiments. Figure 5 is a table showing the common construction conditions for Examples 1 to 3 and the Comparative Example. Figure 6 is a table showing the test results when a flat plate-shaped member was used as the heat-resistant alloy substrate 5. In Figure 6, the test results for Example 1, Example 2, and the Comparative Example are shown as relative values ​​with the Comparative Example's test result set to 1. All results in Figure 6 were performed under the same thermal cycle test conditions. Figure 7 is a graph showing the test results of the thermal cycle endurance test for Example 3.

[0031] The construction conditions in Example 1, Example 3, and the Comparative Example are designated as Construction Condition A, and the construction conditions in Example 2 are designated as Construction Condition B. In each example and comparative example, the dispersion medium of the suspension S and the supply amount of suspension S (material supply amount) differ between construction conditions A and construction condition B, but the following conditions are the same. Specifically, the concentration of Y2O3 in suspension S is 8 wt%, and the concentration of yttria-stabilized zirconia powder is 25 wt%. The thermal spraying distance was set to 70 mm, the traverse speed to 1000 mm / s, and the traverse pitch to 4 mm. The gas flow rates were calculated using a ratio of 85:57:57 for Ar, N2, and H2. The plasma output, i.e., the input power to the thermal spray gun 30, was set to 100 kW. The dispersion medium for suspension S was anhydrous ethanol. The supply rate of suspension S (material supply rate) was set to 45 ml / min under construction condition A and to 63 ml / min under construction condition B.

[0032] In Examples 1 to 3, the water W supply rate from the cooling fluid supply unit 40 was set to 100 ml / min, while in the comparative example, it was set to 0 ml / min. In Figure 6, the water W supply rate from the cooling fluid supply unit 40 is denoted as WS flow rate, which is an abbreviation for water shroud flow rate.

[0033] In Example 1, the porosity of the topcoat layer 9 was 0.7 relative to the comparative example (set as 1), and the thermal conductivity of the topcoat layer 9 was 0.9 relative to the comparative example (set as 1). Furthermore, even at a thermal cycle count of 32 relative to the comparative example (set as 1) in the thermal cycle durability test, the layer remained intact. The porosity was calculated by dividing the total area of ​​the porous portion in a certain range of the SEM image of the cross-section of the test specimen in each example and comparative example by the total area of ​​that range, and expressing the result as a relative value with the comparative example set to 1. Furthermore, in the thermal cycle durability test, the number of cycles until the thermal barrier coating peeled off the test specimen when a temperature difference of 1000 degrees was repeatedly applied was determined, and this number of cycles, or thermal cycle number, was expressed as a relative value with the comparative example set to 1.

[0034] Comparing the test results of Example 1 with those of the comparative example, the porosity decreased by 30%. The thermal conductivity did not increase, but rather decreased by 10%. As mentioned above, the thermal cycle durability was significantly improved, remaining unpeeled even after 32 times the number of thermal cycles compared to the comparative example.

[0035] In Example 2, the porosity of the topcoat layer 9 was 0.1 relative to the comparative example (set as 1), and the thermal conductivity of the topcoat layer 9 was 1.3 relative to the comparative example (set as 1). Furthermore, even at a thermal cycle count of 32 relative to the comparative example (set as 1) in the thermal cycle durability test, the layer remained intact. Comparing the test results of Example 2 with those of the comparative example, the porosity decreased by 90%. The thermal conductivity increased by only 30%. As mentioned above, the thermal cycle durability was significantly improved, with no delamination even after 32 times the number of thermal cycles compared to the comparative example.

[0036] In Example 3, unlike Examples 1, 2, and the Comparative Example, a cylindrical member is used as the heat-resistant alloy substrate 5. Therefore, during thermal spraying, the heat-resistant alloy substrate 5 is rotated around the central axis of the cylinder while the thermal spray gun 30 is also moved. In Examples 1, 2, and the Comparative Example, the heat-resistant alloy substrate 5 remains stationary during thermal spraying, and only the thermal spray gun 30 is moved.

[0037] As shown in Figure 7, in Examples 1 to 3, in the thermal cycle durability test where a temperature difference of 1000 degrees was applied, the number of cycles until the heat-shielding coating peeled off on the test specimen was equivalent to or better than the test results for test specimens in which the topcoat layer 9 was formed by electron beam physical vapor deposition (EB-PVD). However, the test results for test specimens in which the topcoat layer 9 was formed by atmospheric pressure plasma spraying (APS) without supplying water W from the cooling fluid supply unit 40 were not as good as the test results for test specimens in which the topcoat layer 9 was formed by electron beam physical vapor deposition (EB-PVD).

[0038] Figure 8A is an SEM image of a cross-section of a test specimen in which the topcoat layer 9 was formed under the same construction conditions as in Example 1. Figure 8B is a grayscale image of the region enclosed by the dashed line in Figure 8A, which has been color-coded by crystal orientation using image processing. In Figure 8B, the areas shown in black represent pores, crystals whose crystal orientation could not be determined due to their small grain size, or amorphous crystals. Figure 8C is a graph showing the crystal grain size distribution for the region enclosed by the dashed line in Figure 8A. Figure 9A is an SEM image of a cross-section of a test specimen in which the topcoat layer 9 was formed under the same construction conditions as the comparative example described above. Figure 9B is a grayscale image of the region enclosed by the dashed line in Figure 9A, which has been color-coded by crystal orientation using image processing. In Figure 9B, the areas shown in black represent stomata. Figure 9C is a graph showing the crystal grain size distribution for the region enclosed by the dashed line in Figure 9A.

[0039] The average grain size of the crystals in the topcoat layer 9 of the test specimens shown in Figures 8A to 8C was 0.36 μm. Furthermore, the average grain size of the crystals in the topcoat layer 9 of the test specimens shown in Figures 9A to 9C was 1.03 μm. As can be seen from Figures 8A to 8C and Figures 9A to 9C, by performing atmospheric pressure plasma spraying with a suspension while supplying water W from the cooling fluid supply unit 40, cracks in the top coat layer 9 can be suppressed and the average grain size of the crystals can be reduced. The average grain size of the crystals in the top coat layer 9 is preferably 0.3 μm or more and 0.8 μm or less.

[0040] (Regarding the amount of water W supplied from the cooling fluid supply unit 40) Figure 10 is a graph showing the relationship between the amount of water W supplied from the cooling fluid supply unit 40 and the deposition rate, which is the film thickness per thermal spray pass when applying the topcoat layer 9. As shown in Figure 10, the deposition rate was 3.9 or 4.0 μm / path when the water W supply rate was 50 ml / min, 3.4 or 3.5 μm / path when the water W supply rate was 75 ml / min, 2.8 or 3.1 μm / path when the water W supply rate was 100 ml / min, 0.3 μm / path when the water W supply rate was 200 ml / min, 0 μm / path when the water W supply rate was 300 ml / min, and 0 μm / path when the water W supply rate was 400 ml / min. As shown in Figure 10, the film deposition rate decreases as the amount of water W supplied from the cooling fluid supply unit 40 increases. Furthermore, from the test results in Examples 1 to 3 described above, it was found that in step S20, when water W is supplied around the plasma flame P as a cooling fluid at a supply rate of 25 ml / min to 100 ml / min, the thermal cycle durability of the heat shielding coating 3 is significantly improved.

[0041] This disclosure is not limited to the embodiments described above, but also includes modified forms of the embodiments described above, as well as forms that combine these forms as appropriate.

[0042] The contents described in each of the above embodiments can be understood, for example, as follows: (1) A method for applying a heat-shielding coating according to at least one embodiment of the present disclosure comprises a step S20 of forming a top coat layer 9 on a bond coat layer 7 formed on a heat-resistant alloy substrate 5 of an object. In the step S20 of forming the top coat layer 9, a suspension S containing ceramic powder is sprayed by atmospheric pressure plasma spraying while a portion of the plasma flame P is cooled by supplying water W as a cooling fluid around the plasma flame P at a supply rate of 25 ml / min to 100 ml / min.

[0043] According to the method described in (1) above, a topcoat layer 9 can be formed at low cost without performing electron beam physical deposition, and the thermal cycle durability of the heat-shielding coating 3 can be improved.

[0044] According to the method described in (1) above, by using water W as the cooling fluid, the cooling fluid becomes readily available, and because the latent heat of vaporization is relatively large, the area around the plasma flame P can be cooled efficiently, thus providing a good cooling effect at a low cost. As a result of diligent research by the inventors, it was found that in the process of forming the top coat layer 9, supplying water W as a cooling fluid around the plasma flame P at a supply rate of 25 ml / min to 100 ml / min significantly improves the thermal cycle durability of the heat shielding coating 3. According to the method described in (1) above, the thermal cycle durability of the heat-shielding coating 3 can be significantly improved.

[0045] (2) In some embodiments, the ceramic powder in the method of (1) above may contain any of yttria-stabilized zirconia, dysprosia-stabilized zirconia, ervia-stabilized zirconia, Gd2Zr2O7, or Gd2Hf2O7.

[0046] According to the method described in (2) above, a heat-shielding coating 3 with excellent heat-shielding properties can be obtained.

[0047] (3) In some embodiments, in the method of (1) or (2) above, the heat-resistant alloy substrate 5 may be a nickel-based alloy substrate.

[0048] According to the method described in (3) above, the heat resistance of the heat-resistant alloy substrate 5 is improved.

[0049] (4) A heat-resistant member 1 according to at least one embodiment of the present disclosure has a top coat layer 9 formed by a heat-shielding coating application method according to any of the methods (1) to (3) described above.

[0050] According to the configuration described in (4) above, the manufacturing cost of the heat-resistant component 1 can be reduced while improving the thermal cycle durability of the heat-shielding coating 3. [Explanation of Symbols]

[0051] 1 Heat-resistant material 3. Heat-shielding coating 5 Heat-resistant alloy base material (base material) 7. Metallic bonding layer (bond coat layer) 9. Top coat layer 30 Thermal spray gun 35 Supply section 40 Cooling fluid supply unit (water shroud)

Claims

1. The process includes a step of forming a top coat layer on a bond coat layer formed on a heat-resistant alloy substrate of the object, In the process of forming the topcoat layer, the topcoat layer is formed by spraying a suspension containing ceramic powder by atmospheric pressure plasma spraying while cooling a portion of the plasma flame by supplying water as a cooling fluid at a supply rate of 25 ml / min to 100 ml / min, The water used as the cooling fluid is supplied to the area around the plasma flame separately from the suspension. Application method for heat-shielding coating.

2. The ceramic powder comprises any of the following: yttria-stabilized zirconia, dyspurosia-stabilized zirconia, ervia-stabilized zirconia, Gd2Zr2O7, or Gd2Hf2O7. A method for applying the heat-shielding coating described in claim 1.

3. The heat-resistant alloy substrate is a nickel-based alloy substrate. A method for applying a heat-shielding coating according to claim 1 or 2.

4. The supply position of the water as a cooling fluid to the vicinity of the plasma flame is downstream of the supply position of the suspension in the direction of injection of the plasma flame. A method for applying a heat-shielding coating according to any one of claims 1 to 3.

5. The top coat layer is formed of crystals with an average particle size of 0.3 μm or more and 0.8 μm or less. A method for applying a heat-shielding coating according to any one of claims 1 to 4.

6. A method for manufacturing a heat-resistant member having a bond coat layer and a top coat layer formed on a heat-resistant alloy substrate, The process includes forming the top coat layer on the bond coat layer formed on the heat-resistant alloy substrate, In the process of forming the topcoat layer, the topcoat layer is formed by spraying a suspension containing ceramic powder by atmospheric pressure plasma spraying while cooling a portion of the plasma flame by supplying water as a cooling fluid at a supply rate of 25 ml / min to 100 ml / min, The water used as the cooling fluid is supplied to the area around the plasma flame separately from the suspension. A method for manufacturing heat-resistant components.

Images