Method for applying a heat shielding coating and heat resistant member

Abstract

To suppress clogging of multiple cooling holes opened on the surface of a heat resistant member by a material of a thermal barrier coating.SOLUTION: A construction method of thermal barrier coating in at least one embodiment, includes a step for forming, by flame spraying, a top coat layer on a bond coat layer formed on a heat-proof alloy base material, while blowing out gas from multiple holes formed on the surface of the heat-proof alloy base material.SELECTED DRAWING: Figure 13

Description

Technical Field

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

Background Art

[0002] It is known to provide a thermal barrier coating (TBC) on heat-resistant members exposed to high-temperature combustion gases, such as combustor panels and turbine blades in aircraft engines, and turbine blades and split rings in industrial gas turbines. In addition, in these heat-resistant members, for example, in order to perform film cooling, a plurality of cooling holes may be formed in the surface of the heat-resistant member. In such a case of a heat-resistant member, it is necessary to prevent the material of the thermal barrier coating from entering the cooling holes and blocking the cooling holes during the formation process of the thermal barrier coating. Therefore, for example, if masking pins are inserted into each cooling hole in advance, it is possible to prevent the material of the thermal barrier coating from entering each cooling hole during the formation process of the thermal barrier coating (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] (1) A method for applying a heat-shielding coating according to at least one embodiment of the present disclosure comprises the step of forming a top coat layer on a bond coat layer formed on a heat-resistant alloy substrate by thermal spraying while ejecting gas from a plurality of holes opened on the surface of the heat-resistant alloy substrate.

[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, it is possible to prevent a plurality of cooling holes opening on the surface of the heat-resistant member from being blocked by the heat-shielding coating material. [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 4A] This diagram illustrates the general structure of an apparatus related to a method for applying a heat-shielding coating according to several embodiments. [Figure 4B] This figure shows an example of a cooling method to maintain the temperature of the topcoat layer within the temperature range described above. [Figure 5] This graph schematically shows the temperature change of the topcoat layer from the start of thermal spraying. [Figure 6] It is a graph showing the relationship between the thermal conductivity of the top coat layer and the temperature during spraying. [Figure 7] It is a graph showing the relationship between the delamination limit temperature difference and the temperature during spraying. [Figure 8] It is a graph showing the relationship between the delamination limit temperature difference and the transverse crack length. [Figure 9] It is a graph showing the relationship between the deposited film thickness per spraying pass and the temperature during spraying. [Figure 10A] It is a table showing the measurement results of the density of longitudinal cracks dispersed in the plane direction. [Figure 10B] It is a table showing the measurement results of the maximum length of transverse cracks. [Figure 11] It is a diagram for explaining an embodiment regarding the cooling of a heat-resistant member. [Figure 12A] It is a diagram for explaining an embodiment regarding the cooling of a plurality of heat-resistant members. [Figure 12B] It is a diagram for explaining another embodiment regarding the cooling of a plurality of heat-resistant members. [Figure 13] It is a diagram for explaining an embodiment regarding the cooling of a heat-resistant member. [Figure 14] It is a diagram for explaining an embodiment regarding the cooling of a heat-resistant member. [Figure 15] It is a schematic diagram for explaining the construction angle during spraying for a plurality of holes. [Figure 16] It is a graph showing the experimental results regarding the relationship between the diameter of the hole and the blockage rate of the hole by the sprayed material.

Mode for Carrying Out the Invention

[0010] Hereinafter, some embodiments of the present disclosure will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described as embodiments or shown in the drawings are not intended to limit the scope of the present disclosure, but are merely illustrative examples. For example, expressions representing relative or absolute arrangements such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric", or "coaxial" not only strictly represent such arrangements, but also represent states with tolerances or relative displacements with angles or distances such that the same function can be obtained. For example, expressions representing that things are in an equal state such as "identical", "equal", and "homogeneous" not only strictly represent an equal state, but also represent states with tolerances or differences such that the same function can be obtained. For example, expressions representing shapes such as a square shape or a cylindrical shape not only represent shapes such as a square shape or a cylindrical shape in a geometrically strict sense, but also represent shapes including concavo-convex portions, chamfered portions, etc. within a range where the same effect can be obtained. On the other hand, expressions such as "comprising", "having", "including", or "possessing" one component are not exclusive expressions that exclude the existence of other components.

[0011] (Regarding the heat insulation coating 3) FIG. 1 is a schematic cross-sectional view of a heat-resistant member 1 including a heat insulation coating 3 constructed by a method for constructing a heat insulation coating according to some embodiments. FIG. 2 is a view showing the appearance of a combustor panel 1A for an aircraft engine as an example of the heat-resistant member 1. On heat-resistant members 1 such as a combustor panel 1A for an aircraft engine, turbine blades, turbine blades and split rings for an industrial gas turbine, a heat insulation coating (Thermal Barrier Coating: TBC) 3 for heat insulation of the heat-resistant member 1 is formed. 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 as a heat insulation layer are sequentially formed. That is, in some embodiments, the heat insulation coating 3 includes a bond coat layer 7 and a top coat layer 9.

[0012] In some embodiments, the bond coat layer 7 is composed of an MCrAlY alloy (where M represents a metallic element such as Ni, Co, Fe, or a combination of two or more of these).

[0013] In some embodiments, the topcoat layer 9 may be composed of a ZrO2-based material, for example, YSZ (yttria-stabilized zirconia), which is ZrO2 partially or fully stabilized with Y2O3. In some embodiments, the topcoat layer 9 may also be composed of DySZ (dyspurosis-stabilized zirconia), ErSZ (ervia-stabilized zirconia), Gd2Zr2O7, or Gd2Hf2O7. This results in a heat-shielding coating 3 with excellent heat-shielding properties.

[0014] In some embodiments of the topcoat layer 9, longitudinal cracks Cv extending in the thickness direction of the topcoat layer 9 are dispersed in the plane direction, i.e., the left-right direction and the depth direction of the paper in Figure 1. In addition, in some embodiments of the topcoat layer 9, transverse cracks Ch extending in the plane direction are dispersed. In some embodiments of the heat-shielding coating 3, the structure having multiple longitudinal cracks Cv in the top coat layer 9 can mitigate the generation of thermal stress due to the difference in linear expansion coefficient with the heat-resistant alloy substrate 5, thus providing excellent thermal cycle durability.

[0015] (flowchart) Figure 3 is a flowchart showing the procedure for applying a heat-shielding coating according to several embodiments. The application method for a heat-shielding coating according to several embodiments includes a step S10 for forming a bond coat layer 7 and a step S20 for forming a top coat layer 9.

[0016] In some embodiments, step S10 for forming the bond coat layer 7 is a step of forming the bond coat layer 7 on the heat-resistant alloy substrate 5 by thermal spraying. In some embodiments, step S10 for forming the bond coat layer 7 may be a step of forming the bond coat layer on the heat-resistant alloy substrate 5 by high-velocity flame spraying (HVOF), for example. In the following description, step S10 for forming the bond coat layer 7 is assumed to be a step of forming the bond coat layer 7 on the heat-resistant alloy substrate 5 by high-velocity flame spraying. In other words, in some embodiments, in step S10 for forming the bond coat layer 7, powder such as MCrAlY alloy as a thermal spray material is sprayed onto the surface of the heat-resistant alloy substrate 5 by high-speed flame spraying.

[0017] In some embodiments, the surface roughness of the bond coat layer 7 is preferably 8 μm or more in terms of arithmetic mean roughness Ra, in order to improve adhesion with the top coat layer 9.

[0018] 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 sprayed. In some embodiments, in step S20 for forming the topcoat layer 9, the topcoat layer is formed by spraying a suspension containing ceramic powder by high-velocity flame spraying. That is, in some embodiments, the spraying performed in step S20 for forming the topcoat layer 9 is high-velocity flame spraying with a suspension (S-HVOF). In some embodiments, in step S20 for forming the topcoat layer 9, a suspension in which ceramic powder as a spray material is dispersed in a solvent is sprayed onto the surface of the bond coat layer 7 by high-velocity flame spraying. In high-velocity flame spraying with a suspension, the spray material TM supplied as a suspension is blown onto the surface of the object to be sprayed by a combustion flame jet flow CF (see Figure 4B described later). The thermal spraying conditions in step S20, which forms the topcoat layer 9, will be explained in detail later.

[0019] Figure 4A 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 4A, in some embodiments of the heat-shielding coating application method, the heat-shielding coating 3 is applied using a thermal spray gun 30, a mobile device 50 for the thermal spray gun 30, and a dust collection hood 70. In addition to the devices shown in Figure 4A, some embodiments of the heat-shielding coating application method also include, although not shown, a thermal spray control panel, a control device for controlling the drive of the mobile device 50, and a thermal spray material supply device. When applying the heat-shielding coating 3, if it is necessary to fix the heat-resistant member 1, which is the object to be coated with the heat-shielding coating 3, a fixing jig 91 may be used, and if it is necessary to continuously rotate the heat-resistant member 1, a rotary drive device (not shown) may be used.

[0020] In some embodiments, the moving device 50 is, for example, an industrial robot, but it may also be a scanning device having a slide axis that can move in multiple directions, such as an NC device.

[0021] As shown in Figure 4A, in some embodiments of the method for applying a heat-shielding coating, for example, the thermal spray gun 30, the mobile device 50, and the dust collection hood 70 are arranged inside a thermal spray booth 20. The thermal spray booth 20 forms a space partitioned from the surroundings for sound insulation and to prevent dust from scattering into the surroundings. For example, the thermal spray booth 20 may be a box-shaped structure placed in a work room, a section of a work room partitioned by walls, or a dedicated room set up inside a building. The heat-resistant component 1, which is the object to which the heat-shielding coating 3 is applied, has the heat-shielding coating 3 formed inside the thermal spray booth 20.

[0022] In some embodiments of the heat-shielding coating application method, as described above, the step S10 for forming the bond coat layer 7 is performed by high-velocity flame spraying (HVOF), and the step S20 for forming the top coat layer 9 is performed by high-velocity flame spraying (S-HVOF) using a suspension. Therefore, in some embodiments of the heat-shielding coating application method, for example, by changing the spray gun 30 and the spray material supply device between the step S10 for forming the bond coat layer 7 and the step S20 for forming the top coat layer 9, the step S10 for forming the bond coat layer 7 and the step S20 for forming the top coat layer 9 can be performed in the same spray booth 20. In some embodiments of the heat-shielding coating application method, when performing the step of forming the top coat layer 9 in step S20 after the step of forming the bond coat layer 7 in step S10, it is not necessary to move the heat-resistant member 1 to a different thermal spray booth than the one in which the step of forming the bond coat layer 7 in step S10 was performed. This eliminates the effort of moving the heat-resistant member 1 to a different thermal spray booth and the effort of setting up the heat-resistant member 1 after moving it until thermal spraying begins.

[0023] (Regarding the construction conditions in step S20, which involves forming the top coat layer 9) Conventionally, topcoat layers were sometimes formed by electron beam physical vapor deposition (EB-PVD) to ensure thermal cycle durability by incorporating cracks, known as longitudinal cracks, that extend in the thickness direction of the topcoat layer. However, the initial cost of equipment for electron beam physical deposition is more than 10 times higher than that of thermal spraying equipment, etc. Furthermore, the running costs for forming layers by electron beam physical deposition are about 10 times higher than the running costs for forming layers by thermal spraying, etc. Moreover, the layer formation rate by electron beam physical deposition is low, only a fraction of the rate by 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.

[0024] As a result of diligent research by the inventors, it was found that in step S20 for forming the topcoat layer 9, by maintaining the temperature of the topcoat layer 9 between 300°C and 450°C while spraying a suspension containing ceramic powder by high-speed flame spraying, it is possible to ensure performance such as heat shielding and thermal cycle durability equivalent to that obtained when the topcoat layer is formed on the bond coat layer by electron beam physical deposition. Therefore, in the heat-shielding coating application method according to several embodiments, in step S20 for forming the top coat layer 9, the top coat layer 9 is formed by spraying a suspension containing ceramic powder by high-speed flame spraying while maintaining the temperature of the top coat layer 9 at 300°C or higher and 450°C or lower. The inventors' findings will be explained later.

[0025] This allows for the formation of the topcoat layer 9 on the bond coat layer 7 by electron beam physical deposition at a lower running cost and in a shorter time. Furthermore, by forming the topcoat layer 9 by high-speed flame spraying using a suspension, the cost of introducing equipment for forming the topcoat layer 9 can be significantly reduced.

[0026] Furthermore, some heat-resistant members 1 according to certain embodiments have a top coat layer 9 formed by a heat-shielding coating application method according to certain embodiments. This makes it possible to reduce the manufacturing cost of the heat-resistant component 1.

[0027] Furthermore, in step S20, where the topcoat layer 9 is formed, it is preferable to form the topcoat layer 9 by thermal spraying a suspension containing ceramic powder using high-velocity flame spraying while maintaining the temperature of the topcoat layer 9 at 300°C to 400°C. This further improves the performance of the heat-shielding coating, such as its heat-shielding properties and thermal cycle durability.

[0028] Whether the temperature of the topcoat layer 9 is maintained within the above-mentioned temperature range can be confirmed by measuring it with a non-contact thermometer, such as a thermal viewer that detects temperature using infrared light.

[0029] Furthermore, cooling may be performed as needed to maintain the temperature of the top coat layer 9 within the aforementioned temperature range. In other words, in the heat-shielding coating application method according to some embodiments, in step S20 where the top coat layer 9 is formed, it is preferable to control the temperature of the top coat layer 9 by cooling with a cooling medium. This makes it easier to control the temperature of the topcoat layer 9 within the aforementioned temperature range, thus stabilizing the performance of the heat-shielding coating 3, such as its heat shielding properties and thermal cycle durability.

[0030] Figure 4B shows an example of a cooling method to maintain the temperature of the topcoat layer 9 within the temperature range described above. In the example shown in Figure 4B, the heat-resistant member 1 is an axial member. In the example shown in Figure 4B, the topcoat layer 9 is formed on the heat-resistant member 1 while it is being rotated by a rotary drive device (not shown) for continuously rotating the heat-resistant member 1. In the example shown in Figure 4B, the heat-resistant member 1 is held by a gripping part 92 of a rotary drive device (not shown) and rotates together with the gripping part 92. In the example shown in Figure 4B, the heat-resistant member 1 is cooled by a cooling medium CM blown out from a cooling nozzle 81, for example. In the example shown in Figure 4B, in order to suppress the effect of the combustion flame jet flow CF on the cooling medium CM blown out from the cooling nozzle 81, it is preferable that the cooling medium CM be blown out not to the surface of the topcoat layer 9, but to the area 1a of the heat-resistant member 1 where the topcoat layer 9 is not formed, or to the gripping portion 92 that grips the heat-resistant member 1. Other examples of cooling the heat-resistant component 1, as well as the type of cooling medium CM, will be explained later.

[0031] Figure 5 is a schematic graph showing the temperature change of the topcoat layer 9 from the start of thermal spraying. The temperature of the topcoat layer 9 increases as time passes from the time thermal spraying for the formation of the topcoat layer 9 begins. As shown in the example in Figure 4B, by cooling with a cooling medium CM, the temperature of the topcoat layer 9 during thermal spraying can be kept stable within the temperature range described above. In other words, in the heat-shielding coating application method according to some embodiments, in step S20 of forming the top coat layer 9, it is preferable to ensure that the average value of the temperature of the top coat layer 9 in a stable state after the temperature rises after the start of thermal spraying is kept within the above-mentioned temperature range. In the following explanation, this average value will also be referred to as the thermal spray temperature Ta. In addition, in some embodiments of the heat-shielding coating application method, it is not necessary to preheat the heat-resistant member 1 on which the bond coat layer 7 is formed before starting thermal spraying for the formation of the top coat layer 9.

[0032] The inventors' findings are described below. Figure 6 is a graph showing the relationship between the thermal conductivity (relative value) of the topcoat layer 9 and the thermal spray temperature Ta for test specimen A, test specimen B, and test specimen C, which have a thermal spray temperature Ta of 413°C, 477°C, and 586°C, respectively. Figure 7 is a graph showing the relationship between the peel limit temperature difference ΔT (relative value) and the thermal spray temperature Ta for test specimens A, B, and C. Figure 8 is a graph showing the relationship between the peel limit temperature difference ΔT (relative value) and the length of the transverse crack Ch (transverse crack length) for test specimens A, B, and C. Figure 9 is a graph showing the relationship between the deposition film thickness per thermal spray pass (relative value) and the thermal spray temperature Ta for test specimens A, B, C, and D, where the thermal spray temperature Ta was 678°C. Figure 10A is a table showing the measurement results of the density of longitudinal cracks Cv dispersed in the planar direction for test specimens A, B, and C. Figure 10B is a table showing the measurement results for the maximum length of transverse cracks Ch for test specimens A, B, and C.

[0033] In Figure 6, the thermal conductivity of the topcoat layer 9 is expressed as a relative value, with the thermal conductivity of the topcoat layer formed by electron beam physical vapor deposition (EB-PVD) set to 1. Similarly, in Figures 7 and 8, the peeling limit temperature difference ΔT of the topcoat layer 9 is expressed as a relative value with the peeling limit temperature difference ΔT of the topcoat layer formed by electron beam physical deposition set to 1. Note that the peeling limit temperature difference ΔT in Figures 7 and 8 is the temperature difference at which peeling is estimated to occur in the heat-shielding coating 3 when this temperature difference ΔT is applied in a test that is repeated 1000 times. In Figure 9, the adhesion thickness of the topcoat layer 9 per pass is expressed as a relative value, with the adhesion thickness per pass at a thermal spraying temperature Ta of 450°C set to 1. In order to obtain the data shown in Figures 10A and 10B, the data was acquired by observing micrographs of the cross-sections obtained by cutting each test specimen along the thickness direction of the topcoat layer 9. In addition, in Figures 10A and 10B, data was acquired at six different observation sites (six fields of view) on the cross-section. In acquiring the data shown in Figures 10A and 10B, the field of view corresponding to the left-right direction in Figure 1 was 1.09 mm in each microscope image. Therefore, the number of longitudinal fissures Cv and the maximum length of transverse fissures Ch observed within this field of view were obtained.

[0034] The thermal spraying conditions for test specimens A, B, C, and D, other than the thermal spraying temperature Ta, are as follows: Test specimens A to D are cylindrical specimens as shown in Figure 4B. A topcoat layer 9 was formed on the bond coat layer 7 formed on the outer circumference of test specimens A to D by high-speed flame spraying of a suspension. The traverse speed of the thermal spray gun 30 is 100 mm / second. The film thickness of the topcoat layer 9 is 0.5 mm. The rotation speed of the cylindrical test specimen is 1200 rpm. During thermal spraying of the test specimen, the thermal spray gun 30 is moved from the starting position for film deposition on one side in the vertical direction shown in Figure 4B to the other side while depositing the film. After the thermal spray gun 30 reaches the end position for film deposition on the other side, the thermal spray gun 30 is moved in the depth direction of the paper in Figure 4B to avoid the combustion flame jet CF from hitting the test specimen, and then moved towards the one side in the vertical direction shown in Figure 4B. Then, the thermal spray gun 30 is moved back to the starting position for film deposition in the depth direction of the paper in Figure 4B, and the above operation is repeated thereafter to form the topcoat layer 9.

[0035] As shown in Figure 6, by setting the thermal spraying temperature Ta to 450°C or lower, the thermal conductivity of the topcoat layer 9 can be made equivalent to or lower than that of the layer formed by electron beam physical deposition. Furthermore, as shown in Figure 6, the thermal conductivity of the topcoat layer 9 can be further reduced by setting the thermal spraying temperature Ta to 400°C or lower. As shown in Figure 7, by setting the thermal spraying temperature Ta to 400°C or lower, the peeling limit temperature difference ΔT of the topcoat layer 9 can be made equivalent to or greater than that when formed by electron beam physical deposition. Furthermore, the peeling limit temperature difference ΔT of the topcoat layer 9 may be around 0.8 as a relative value in Figure 7. Therefore, by setting the thermal spraying temperature Ta to 450°C or lower, the peeling limit temperature difference ΔT of the topcoat layer 9 can be set to be greater than or equal to the required temperature difference. Therefore, the thermal spray temperature Ta should ideally be 450°C or lower, and even better, 400°C or lower.

[0036] As shown in Figures 8 and 10B, it can be seen that the length of transverse cracks Ch tends to increase as the thermal spray temperature Ta increases. Furthermore, it can be seen that the peeling limit temperature difference ΔT of the topcoat layer 9 tends to decrease as the length of transverse cracks Ch increases. Since the growth of transverse cracks Ch causes peeling of the topcoat layer 9 and reduces thermal cycle durability, it is desirable for the length of transverse cracks Ch to be small. Note that each plot shown in Figure 8 is based on the data shown in Figure 10B.

[0037] As shown in Figure 10A, the density of longitudinal cracks Cv dispersed in the plane increases as the thermal spray temperature Ta increases. A higher density of longitudinal cracks Cv dispersed in the plane improves thermal cycle durability, but increasing the density of longitudinal cracks Cv dispersed in the plane tends to increase the length of transverse cracks Ch. Therefore, a density of longitudinal cracks Cv dispersed in the plane of about 4 cracks / mm is sufficient.

[0038] As shown in Figure 9, when the thermal spraying temperature Ta decreases, the thickness of the coating per thermal spray pass decreases. Therefore, when the thermal spraying temperature Ta decreases, the productivity of the topcoat layer 9 decreases. As shown in Figure 9, when the thermal spraying temperature Ta falls below 300°C, the coating thickness per thermal spray pass is less than half of what it is when the thermal spraying temperature Ta is 450°C. Therefore, the thermal spray temperature Ta is preferably 300°C.

[0039] (Regarding the cooling of heat-resistant component 1) Figure 11 is a diagram illustrating an example of cooling the heat-resistant component 1. Figure 12A is a diagram illustrating an example of cooling multiple heat-resistant components 1. Figure 12B is a diagram illustrating another embodiment relating to the cooling of multiple heat-resistant members 1. Figure 13 is a diagram illustrating an example of cooling the heat-resistant component 1. Figure 14 is a diagram illustrating an example of cooling the heat-resistant component 1.

[0040] As shown in Figure 11, for example, when a topcoat layer 9 is formed on one surface of a plate-shaped heat-resistant member 1, the heat-resistant member 1 may be cooled by blowing a cooling medium CM toward the other surface opposite to the one surface.

[0041] As shown in Figures 12A and 12B, in step S20 for forming the topcoat layer 9, the topcoat layer 9 may be formed by sequentially thermal spraying onto multiple heat-resistant members 1 attached to jigs 93 and 94. This allows for the efficient formation of a topcoat layer 9 on multiple heat-resistant components 1.

[0042] In other words, as shown in Figure 12A, multiple heat-resistant members 1 may be arranged in a line, and thermal spraying may be performed on multiple heat-resistant members 1 in a single pass. In this case, for example, multiple heat-resistant members 1 arranged in a linear or planar manner may be held by a jig 93. As shown in Figure 12A, each heat-resistant member 1 may be cooled by blowing the cooling medium CM toward the side of the heat-resistant member 1 that is opposite to the side forming the top coat layer 9, when multiple heat-resistant members 1 are arranged in a row. Furthermore, as shown in Figure 12A, if multiple heat-resistant members 1 are arranged side by side and thermal spraying is performed on multiple heat-resistant members 1 in one pass, the interval between thermal spraying passes becomes longer compared to when thermal spraying is performed on a single heat-resistant member 1, so the temperature of the topcoat layer 9 does not rise easily. For this reason, if the thermal spraying temperature Ta can be maintained within the above-mentioned temperature range without cooling each heat-resistant member 1 by blowing out the cooling medium CM, cooling with the cooling medium CM is not essential.

[0043] As shown in Figure 12B, the heat-resistant members 1 arranged in a ring shape may be rotated relative to the thermal spray gun 30 to perform thermal spraying on the multiple heat-resistant members 1. In this case, for example, the multiple heat-resistant members 1 arranged in a ring shape may be held by a jig 94. That is, it is preferable that the jig 94 is capable of holding the multiple heat-resistant members 1 arranged in a ring shape. Then, in step S20 for forming the top coat layer 9, it is preferable to sequentially spray the multiple heat-resistant members 1 while rotating the multiple heat-resistant members 1 held by the jig 94 and the thermal spray gun 30 relative to each other.

[0044] Alternatively, the multiple heat-resistant members 1 arranged in a ring shape may be fixed in place and the thermal spraying gun 30 may be rotated to perform thermal spraying, or the thermal spraying gun 30 may be fixed in place and the multiple heat-resistant members 1 arranged in a ring shape may be rotated to perform thermal spraying. When multiple heat-resistant components 1 are rotated, a speed difference is created between each heat-resistant component 1 and the surrounding air. This provides a cooling effect similar to that obtained when air is blown onto each heat-resistant component 1, allowing each heat-resistant component 1 to be cooled efficiently.

[0045] For example, as shown in Figures 13 and 14, if the heat-resistant member 1 has a plurality of holes 110 opened on the surface of the heat-resistant alloy substrate 5, such as so-called film cooling holes, the top coat layer 9 may be formed by ejecting gas (cooling medium CM) from the plurality of holes 110. This makes it easier to control the thermal spray temperature Ta within the aforementioned temperature range, thus stabilizing the performance of the heat-shielding coating 3, such as its heat shielding properties and thermal cycle durability.

[0046] Furthermore, if, for example, a combustor panel 1A as shown in Figure 2 has multiple holes communicating between one side and the other side, then, as shown in Figure 13, for example, gas may be injected into the side opposite to the side forming the topcoat layer 9 to cause gas to be ejected from the multiple holes 110.

[0047] Furthermore, if, for example, a plurality of holes 110 in a turbine blade communicate with a cooling passage inside the blade, and the plurality of holes 110 communicate with a passage 120 inside the heat-resistant member 1 (see Figure 14), gas (cooling medium CM) may be supplied to the passage 120 communicating with the plurality of holes 110 to cause the gas to be ejected from the plurality of holes 110.

[0048] (Regarding the cooling medium CM) In some embodiments, the cooling medium CM may be compressed air compressed by a compressor. Using compressed air from a compressor makes it easier to secure the cooling medium (CM), thus suppressing increased cooling costs. The compressed air used as the cooling medium CM may be compressed air produced by a compressor used to generate compressed air for factory power, or it may be compressed air produced by a compressor installed for cooling the heat-resistant component 1.

[0049] In some embodiments, the cooling medium CM may also include dry ice. In other words, the cooling medium CM may be a system in which relatively small particles or powder of dry ice are transported by compressed air, or it may be carbon dioxide, which is the vaporized dry ice with a relatively low temperature. This reduces the risk of the topcoat layer 9 becoming too hot during its formation, and stabilizes the performance of the heat-shielding coating 3, such as its heat-shielding properties and thermal cycle durability.

[0050] (Regarding the suppression of blockage of multiple holes 110 opened on the surface of the heat-resistant alloy substrate 5) As described above, in some embodiments of the heat-resistant member 1, for example, a plurality of holes 110 (hereinafter also referred to as cooling holes 110) may be opened on the surface of the heat-resistant member 1 in order to cool the film. In the case of such a heat-resistant member 1, it is necessary to prevent the material of the heat-shielding coating (thermal spray material) from entering the cooling holes 110 and blocking them during the process of forming the heat-shielding coating. For this reason, for example, if masking pins are inserted into each cooling hole 110 in advance, it is possible to prevent the material of the heat-shielding coating from entering each cooling hole 110 during the process of forming the heat-shielding coating.

[0051] However, when masking pins are used, the masking pins must be removed from each cooling hole 110 after the heat-shielding coating is formed. Therefore, the more cooling holes 110 there are in the heat-resistant member 1, the more effort is required to remove the masking pins. For this reason, it is desirable to be able to prevent the cooling holes 110 from becoming blocked during the heat-shielding coating formation process using a simpler method.

[0052] Therefore, in the heat-shielding coating application method according to some embodiments, for example, in step S10 for forming the bond coat layer 7, the bond coat layer 7 may be formed on the heat-resistant alloy substrate 5 by thermal spraying while gas is ejected from a plurality of holes 110 opened on the surface of the heat-resistant alloy substrate 5. That is, in the heat-shielding coating application method according to some embodiments, for example, step S10 for forming the bond coat layer 7 may be a step in which the bond coat layer 7 is formed on the heat-resistant alloy substrate 5 by thermal spraying while gas is ejected from a plurality of holes 110. In this way, by forming the bond coat layer 7 while ejecting gas from multiple holes 110, the penetration of the bond coat layer material (thermal spray material) into these multiple holes 110 is suppressed. As a result, in step S10 of forming the bond coat layer 7, it is possible to suppress the blockage of these multiple holes 110 by the bond coat layer material.

[0053] As mentioned above, in step S10, for example, in forming the bond coat layer 7, it is preferable to form the bond coat layer 7 on the heat-resistant alloy substrate 5 by high-speed flame spraying while ejecting gas from a plurality of holes 110. This allows the bond coat layer 7 to be formed by high-speed flame spraying while suppressing the blockage of multiple holes 110 by the bond coat layer 7 material.

[0054] Furthermore, in the heat-shielding coating application method according to some embodiments, for example, in step S20 of forming the top coat layer 9, the top coat layer 9 may be formed by thermal spraying onto the bond coat layer 7 formed on the heat-resistant alloy substrate 5 while gas is ejected from a plurality of holes 110 opened on the surface of the heat-resistant alloy substrate 5. That is, in the heat-shielding coating application method according to some embodiments, for example, step S20 of forming the top coat layer 9 may be a step of forming the top coat layer 9 by thermal spraying onto the bond coat layer 7 formed on the heat-resistant alloy substrate 5 while gas is ejected from a plurality of holes 110. In this way, by forming the topcoat layer 9 while ejecting gas from multiple holes 110, the penetration of the topcoat layer material (thermal spray material, i.e., ceramic powder) into these multiple holes 110 is suppressed. This prevents the multiple holes 110 from becoming blocked by the topcoat layer material in step S20 of forming the topcoat layer 9. Furthermore, in step S20, where the topcoat layer 9 is formed, if the temperature of the topcoat layer 9 rises excessively due to thermal spraying, the above-mentioned problems may occur. In such cases, the excessive rise in temperature of the topcoat layer 9 can be suppressed by ejecting gas from multiple holes 110.

[0055] As mentioned above, for example, in step S20 of forming the top coat layer 9, the top coat layer 9 may be formed by spraying a suspension containing ceramic powder by high-speed flame spraying while ejecting gas from a plurality of holes 110. This allows for the formation of the topcoat layer 9 on the bond coat layer 7 by electron beam physical deposition at a lower running cost and in a shorter time. Furthermore, by forming the topcoat layer 9 by high-speed flame spraying using a suspension, the cost of introducing equipment for forming the topcoat layer 9 can be significantly reduced.

[0056] As mentioned above, if, for example, a combustor panel 1A as shown in Figure 2 has multiple holes communicating between one side and the other side, then, as shown in Figure 13, for example, gas can be injected into the side opposite to the side forming the topcoat layer 9 to expel the gas from the multiple holes 110. This makes it easy to expel gas from the multiple holes.

[0057] Furthermore, as shown in Figure 14, if the multiple holes 110 are in communication with the internal passage 120 of the heat-resistant member 1, as described above, gas (cooling medium CM) may be supplied to the passage 120 communicating with the multiple holes 110 to cause the gas to be ejected from the multiple holes 110. By supplying gas to this passage 120, the gas can be easily ejected from the multiple holes 110.

[0058] As described above, suppressing the blockage of the cooling holes 110 by the thermal spray material by ejecting gas from multiple holes during the heat-shielding coating formation process is effective regardless of the thermal spraying method. In other words, it is effective in thermal spraying such as atmospheric pressure plasma spraying (APS), high-velocity flame spraying (HVOF), atmospheric pressure plasma spraying with suspension (S-APS), and high-velocity flame spraying with suspension (S-HVOF).

[0059] Figure 15 is a schematic diagram illustrating the application angle during thermal spraying for multiple holes 110. In some embodiments, the application angle θa during thermal spraying with respect to the hole 110 is the difference in angle between the extending direction of the hole 110 and the spraying direction of the thermal spray material (the extending direction of the nozzle 31 of the thermal spray gun 30). In some embodiments, the inclination angle θb of the hole 110 is the difference in angle between the extending direction of the surface 5a of the heat-resistant alloy substrate 5 and the extending direction of the hole 110.

[0060] When the construction angle θa is around 90 degrees, the holes 110 become blocked by the thermal spray material, and as the construction angle θa gradually decreases from 90 degrees and approaches 0 degrees, the holes 110 tend to become less likely to be blocked. Furthermore, in atmospheric pressure plasma spraying (APS), for example, a high-temperature plasma jet is used to melt the spray material and adhere it to the substrate. In contrast, in high-velocity flaming (HVOF) and supersonic high-velocity flaming with suspension (S-HVOF), the spray material is made to adhere to the substrate by impacting it at supersonic speeds. Therefore, as the application angle θa gradually decreases from 90 degrees, high-velocity flaming (HVOF) and supersonic high-velocity flaming with suspension (S-HVOF) tend to make it more difficult for the holes 110 to be blocked than in atmospheric pressure plasma spraying (APS).

[0061] In addition, in the heat-shielding coating application method according to some embodiments, in step S20 of forming the top coat layer 9, it is preferable to set the difference in angle between the direction of extension of the holes and the spraying direction of the thermal spray material, i.e., the application angle θa, to 0 degrees or more and 80 degrees or less when performing thermal spraying.

[0062] As a result of diligent research by the inventors, it was found that setting the application angle θa to 0 degrees or more and 80 degrees or less when thermal spraying is even more effective in preventing the holes 110 from being blocked by the material of the topcoat layer 9. Therefore, in the heat-shielding coating application methods according to some embodiments, by setting the application angle θa to 0 degrees or more and 80 degrees or less and performing thermal spraying, it is possible to effectively suppress the blockage of the holes 110 by the material of the topcoat layer.

[0063] In some embodiments of the heat-shielding coating application method, the diameter of the hole 110 is preferably greater than 0.5 mm (for example, 0.533 mm or more).

[0064] As a result of diligent research by the inventors, it was found that, as described later, in order to prevent the holes 110 from being blocked by the material of the topcoat layer 9, it is even better if the diameter of the holes 110 is greater than 0.5 mm (for example, 0.533 mm or more). Therefore, in the heat-shielding coating application methods according to some embodiments, by setting the diameter of the holes 110 to be larger than 0.5 mm (for example, 0.533 mm or more) and performing thermal spraying, it is possible to effectively suppress the blockage of the holes 110 by the material of the topcoat layer 9.

[0065] Figure 16 is a graph showing the experimental results regarding the relationship between the hole diameter (diameter) of hole 110 and the rate of blockage of hole 110 by the thermal spray material. The results shown in Figure 16 illustrate the degree of blockage of hole 110 when the inclination angle θb of hole 110 is 30 degrees and the construction angle θa is 60 degrees, depending on the thermal spraying method and whether or not gas (air) is ejected from hole 110. In the experiment shown in Figure 16, a bond coat layer 7 and a top coat layer 9 were sequentially formed on the surface of a heat-resistant alloy test piece corresponding to the heat-resistant alloy substrate 5 described above. In the experiment shown in Figure 16, the top coat layer 9 was formed by high-speed flame spraying using a suspension, with the target thickness set to be equivalent to the thickness in the actual machine.

[0066] The blockage rate on the vertical axis of the graph shown in Figure 16 is the percentage of the value obtained by dividing the pore diameter Da of the pore 110 after the formation of the topcoat layer 9 by the pore diameter Db of the pore 110 after the formation of the bond coat layer 7. Note that the pore diameter Db of the pore 110 after the formation of the bond coat layer 7 tends to be smaller than the pore diameter of the pore 110 before the formation of the bond coat layer 7 because a portion of the pore 110 is blocked by the thermal spray material of the bond coat layer 7. The pore diameter on the horizontal axis of the graph shown in Figure 16 represents the pore diameter of pore 110 before the formation of the bond coat layer 7.

[0067] As shown in Figure 16, when thermal spraying is performed without ejecting air from the hole 110, the blockage rate becomes 100% if the hole diameter of 110 is 0.5 mm or less. However, if the hole diameter of 110 is greater than 0.5 mm (for example, 0.533 mm or more), the blockage rate is less than approximately 50%. Furthermore, as shown in Figure 16, when thermal spraying is performed without ejecting air from the holes 110, the blockage rate is smaller when the topcoat layer 9 is formed by atmospheric pressure plasma spraying with a suspension than when the topcoat layer 9 is formed by atmospheric pressure plasma spraying with a suspension.

[0068] As shown in Figure 16, when the topcoat layer 9 is formed by atmospheric pressure plasma spraying with a suspension, and when the topcoat layer 9 is formed by high-velocity flame spraying with a suspension, the occlusion rate is smaller when spraying is performed while air is ejected from the holes 110 than when spraying is performed without ejecting air from the holes 110.

[0069] 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.

[0070] 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 by thermal spraying while ejecting gas from a plurality of holes 110 opened in the surface 5a of the heat-resistant alloy substrate 5.

[0071] According to the method described in (1) above, by forming the topcoat layer 9 while ejecting gas from multiple holes 110, the penetration of the topcoat layer material into these multiple holes 110 is suppressed. This prevents the multiple holes 110 from becoming blocked by the topcoat layer material during the process of forming the topcoat layer 9 by thermal spraying (S20). Furthermore, in the process of forming the topcoat layer 9 by thermal spraying (S20), if there is a risk of problems arising due to an excessive rise in the temperature of the topcoat layer 9 caused by thermal spraying, the excessive rise in the temperature of the topcoat layer 9 can be suppressed by ejecting gas from multiple holes 110.

[0072] (2) In some embodiments, in the step (S20) of forming the top coat layer 9 by thermal spraying in the method of (1) above, gas may be ejected from the plurality of holes 110 by spraying gas onto the surface of the heat-resistant alloy substrate 5 opposite to the surface 5a.

[0073] According to the method described in (2) above, if one end of the plurality of holes 110 opens to the surface 5a of the heat-resistant alloy substrate 5 and the other end opens to the opposite surface, gas can be easily ejected from the plurality of holes 110.

[0074] (3) In some embodiments, in the step (S20) of forming the top coat layer 9 by thermal spraying in the method of (1) above, gas may be supplied to the passage 120 communicating with the plurality of holes 110 to cause the gas to be ejected from the plurality of holes 110.

[0075] According to the method described in (3) above, by supplying gas to the passage 120, the gas can be easily ejected from the multiple holes 110.

[0076] (4) In some embodiments, in the step (S20) of forming the top coat layer 9 by thermal spraying in any of the methods (1) to (3) above, it is preferable to set the angle difference between the extending direction of the holes 110 and the spraying direction of the thermal spray material (working angle θa) to 0 degrees or more and 80 degrees or less when performing thermal spraying.

[0077] As a result of diligent research by the inventors, it was found that in order to prevent the holes 110 from being blocked by the material of the topcoat layer 9, it is even better to set the angle difference between the direction in which the holes 110 extend and the spraying direction of the thermal spray material (construction angle θa) to 0 degrees or more and 80 degrees or less when thermal spraying. According to the method described in (4) above, the blockage of the pores 110 by the material of the topcoat layer 9 can be effectively suppressed.

[0078] (5) In some embodiments, in any of the methods (1) to (4) above, the diameter of the hole 110 may be greater than 0.5 mm (for example, 0.533 mm or more).

[0079] After diligent research by the inventors, it was found that in order to prevent the holes 110 from becoming blocked by the material of the topcoat layer 9, it is even better if the diameter of the holes 110 is greater than 0.5 mm (for example, 0.533 mm or more). According to the method described in (5) above, the blockage of the pores 110 by the material of the topcoat layer 9 can be effectively suppressed.

[0080] (6) In some embodiments, in any of the methods (1) to (5) described above, the step (S20) of forming the top coat layer 9 by thermal spraying may be performed by thermal spraying a suspension containing ceramic powder by high-velocity flame spraying to form the top coat layer 9.

[0081] According to the method described in (6) above, the topcoat layer 9 can be formed on the bond coat layer 7 by electron beam physical deposition at a lower running cost and in a shorter time. Furthermore, according to the method described in (6) above, the cost of introducing equipment for forming the topcoat layer 9 can be significantly reduced.

[0082] (7) In some embodiments, the method of (1) to (6) above may further include a step (S10) of forming a bond coat layer 7 on the heat-resistant alloy substrate 5 by thermal spraying while ejecting gas from the plurality of holes 110.

[0083] According to the method described in (7) above, by forming the bond coat layer 7 while ejecting gas from the multiple holes 110, the penetration of the bond coat layer material into these multiple holes 110 is suppressed. This prevents the multiple holes 110 from becoming blocked by the bond coat layer material during the process of forming the bond coat layer 7 by thermal spraying.

[0084] (8) In some embodiments, in the method of (7) described above, the bond coat layer 7 may be formed on the heat-resistant alloy substrate 5 by high-speed flame spraying in step (S10).

[0085] According to the method described in (8) above, the bond coat layer 7 can be formed by high-speed flame spraying while suppressing the blockage of multiple holes 110 by the bond coat layer 7 material.

[0086] (9) 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 (8) described above.

[0087] According to the configuration described in (9) above, the blockage of the multiple holes 110 by the material of the top coat layer 9 is suppressed, thereby improving the reliability of cooling the heat-resistant member 1 by film cooling. [Explanation of symbols]

[0088] 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 20 Thermal spray booths 30 Thermal spray gun 50 Mobile device 70 Dust collection hood 81 Cooling nozzle 93, 94 Jig

Claims

1. forming a top coat layer on the bond coat layer formed on the heat-resistant alloy substrate by thermal spraying while ejecting gas from a plurality of holes opened on the surface of the heat-resistant alloy substrate; Equipped with How to apply heat-shielding coating.

2. In the step of forming the topcoat layer by thermal spraying, the gas is sprayed onto a surface of the heat-resistant alloy substrate opposite to the surface of the heat-resistant alloy substrate, thereby ejecting the gas from the plurality of holes. A method for applying the thermal barrier coating according to claim 1.

3. In the step of forming the top coat layer by thermal spraying, the gas is supplied to a passage communicating with the plurality of holes, and the gas is ejected from the plurality of holes. A method for applying the thermal barrier coating according to claim 1.

4. In the step of forming the top coat layer by thermal spraying, the difference in angle between the extending direction of the holes and the spraying direction of the thermal spraying material is set to be 0 degrees or more and 80 degrees or less. A method for applying the thermal barrier coating according to any one of claims 1 to 3.

5. The diameter of the hole is greater than 0.5 mm A method for applying the thermal barrier coating according to any one of claims 1 to 4.

6. In the step of forming the top coat layer by thermal spraying, the top coat layer is formed by spraying a suspension containing ceramic powder by high-velocity flame spraying. A method for applying the thermal barrier coating according to any one of claims 1 to 5.

7. forming the bond coat layer on the heat-resistant alloy substrate by thermal spraying while ejecting gas from the plurality of holes; Further equipped A method for applying the thermal barrier coating according to any one of claims 1 to 6.

8. In the step of forming the bond coat layer by thermal spraying, the bond coat layer is formed on the heat-resistant alloy substrate by high velocity flame spraying. A method for applying the thermal barrier coating according to claim 7.

9. A high-temperature resistant component having a top coat layer formed by the method for applying a thermal barrier coating according to any one of claims 1 to 8.

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