Heat-resistant coating material, heat-resistant component, and method for manufacturing heat-resistant coating material

Abstract

To provide: a heat-resistant coating material suppressing a ceramic layer from being peeled from a metal component in a high temperature environment; to provide a heat-resistant component; and to provide a method for manufacturing the heat-resistant coating material.SOLUTION: A heat-resistant coating material 2 for a metal component 1 including a metallic porous body 21 and a ceramic layer 23 is provided. The metallic porous body 21 is provided on the surface of the metallic component 1. The ceramic layer 23 covers the surface of the metallic porous body 21. An average pore diameter of the metallic porous body 21 may be 0.5-3.2 mm. The heat-resistant coating material 2 may further include a ground layer 22 formed on the surface of the metallic porous body 1. In this case, the ceramic layer 23 may cover the surface of the ground layer 22.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a heat-resistant coating material for metal parts, a heat-resistant part using the same, and a method for producing the heat-resistant coating material. [Background technology]

[0002] A technique is known for coating the surface of a metal part with a ceramic layer as a thermal barrier layer by thermal spraying in order to improve the heat resistance of the metal part (see, for example, Patent Document 1 below). A base layer is formed on the surface of the metal part, and a ceramic layer is coated on the surface of the base layer, thereby improving the adhesion of the ceramic layer to the metal part. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 6-136505 Summary of the Invention [Problem to be solved by the invention]

[0004] When a ceramic layer is coated on a metal part, the ceramic layer is likely to peel off from the surface of the metal part in a high-temperature environment due to the difference in linear expansion coefficient between metal and ceramic. Even if a base layer is formed on the surface of the metal part as described above and a ceramic layer is coated on the surface of the base layer, it is difficult to prevent the ceramic layer from peeling off from the metal part in a high-temperature environment exceeding 1000°C.

[0005] The present invention has been made in consideration of the above-mentioned circumstances, and has an object to provide a heat-resistant coating material and a heat-resistant component that can suppress peeling of a ceramic layer from a metal component in a high-temperature environment, as well as a method for manufacturing a heat-resistant coating material. [Means for solving the problem]

[0006] (1) A heat-resistant coating material according to the present invention is a heat-resistant coating material for a metal part, and includes a porous metal body and a ceramic layer. The porous metal body is provided on a surface of the metal part. The ceramic layer covers the surface of the porous metal body.

[0007] According to this configuration, the thermal stress occurring between the metal part and the ceramic layer can be alleviated by the highly flexible porous metal body, and therefore it is possible to provide a heat-resistant coating material that can suppress peeling of the ceramic layer from the metal part in a high-temperature environment.

[0008] (2) The average pore size of the porous metal body may be 0.5 to 3.2 mm.

[0009] According to this configuration, the small pores of the porous metal body can be reliably covered with the ceramic layer while the flexibility of the porous metal body is sufficiently ensured.

[0010] (3) The heat-resistant coating material may further include an underlayer formed on the surface of the metal porous body, in which case the ceramic layer may cover the surface of the underlayer.

[0011] According to this configuration, the underlayer can suppress peeling of the ceramic layer from the porous metal body.

[0012] (4) A heat-resistant component according to the present invention includes the heat-resistant coating material and a metal component having the heat-resistant coating material provided on a surface thereof.

[0013] According to this configuration, the thermal stress occurring between the metal component and the ceramic layer can be alleviated by the highly flexible porous metal body, and therefore it is possible to provide a heat-resistant component that can suppress peeling of the ceramic layer from the metal component in a high-temperature environment.

[0014] (5) In the method for producing a heat-resistant coating material according to the present invention, a ceramic layer is spray-coated onto the surface of a porous metal body to be provided on the surface of a metal part, thereby producing a heat-resistant coating material.

[0015] According to this configuration, the thermal stress occurring between the metal part and the ceramic layer can be alleviated by the highly flexible porous metal body, and therefore it is possible to provide a method for producing a heat-resistant coating material that can suppress peeling of the ceramic layer from the metal part in a high-temperature environment. Effect of the Invention

[0016] According to the present invention, the thermal stress occurring between the metal part and the ceramic layer can be alleviated by the use of a metal porous body with excellent flexibility, thereby making it possible to suppress peeling of the ceramic layer from the metal part in a high-temperature environment. [Brief description of the drawings]

[0017] [Figure 1] 1 is a schematic cross-sectional view showing a configuration example of a heat-resistant part according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a diagram for explaining an example of a heat-resistant coating material. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] 1. Heat-resistant component configuration 1 is a schematic cross-sectional view showing an example of the configuration of a heat-resistant component according to the present embodiment. In the present embodiment, a heat-resistant component having a heat-resistant coating material 2 provided on the surface of a metal component 1 will be described.

[0019] For example, the heat-resistant part according to this embodiment is used in gas turbines, heating furnaces such as rotary kilns, etc. The material, shape, and application of the metal part 1 are not particularly limited, but the present invention can be suitably used for the metal part 1 used in a high-temperature environment (e.g., 1000°C or higher).

[0020] The heat-resistant coating material 2 includes a porous metal body 21, an underlayer 22, and a ceramic layer 23. Specifically, the porous metal body 21 is provided on the surface of the metal component 1, and the underlayer 22 is formed on the surface of the porous metal body 21. The ceramic layer 23 is formed on the surface of the underlayer 22 opposite to the porous metal body 21 side, thereby covering the surface of the underlayer 22. In this way, the heat-resistant coating material 2 in which the surface of the porous metal body 21 is covered with the ceramic layer 23 is formed.

[0021] However, the underlayer 22 may be omitted, and the surface of the porous metal body 21 may be directly coated with the ceramic layer 23. Furthermore, another layer may be formed between the porous metal body 21 and the underlayer 22, or between the underlayer 22 and the ceramic layer 23. When the underlayer 22 is omitted, another layer may be formed between the porous metal body 21 and the ceramic layer 23.

[0022] The metal porous body 21 is made of a metal with many pores formed on the surface and inside, and can be made of, for example, a metal fiber sintered body, a metal mesh laminated sintered body, a metal powder sintered body, or a foamed metal. Examples of materials for the metal porous body 21 include nickel-based metals such as pure nickel, nickel alloys such as NiCr and NiSn, but are not limited to these. The average value of the pore diameters of the many pores formed in the metal porous body 21 is the average pore diameter, and the larger this average pore diameter is, the more easily the undercoat layer 22 and the ceramic layer 23 formed on the surface of the metal porous body 21 penetrate into the metal porous body 21 through the pores.

[0023] If necessary, a blasting treatment may be performed on the surface of the porous metal body 21, and a base layer 22 may be formed on the roughened surface of the porous metal body 21 after the blasting treatment. The blasting treatment may be performed using a ceramic powder such as Al2O3, but the blasting treatment may also be performed using other materials.

[0024] The underlayer 22 is a thin film formed of a material such as NiCr, Mo, or MCrAlY, and preferably has a thickness of about 0.05 to 0.3 mm. The underlayer 22 can be formed by various thermal spraying methods such as atmospheric plasma spraying, arc spraying, or high velocity flame spraying, but may be formed by methods other than thermal spraying. The underlayer 22 is not limited to the above materials, and can be formed of any material such as pure metal, alloy, or cermet.

[0025] The ceramic layer 23 is a thin film formed of ceramic, and may be formed using one type of material selected from oxide ceramics such as Al2O3, Al2O3-SiO2, Al2O3-TiO2, ZrO2-Y2O3, ZrO2-CaO, etc. However, the ceramic layer 23 is not limited to oxide ceramics, and may also be formed using non-oxide ceramics such as nitride ceramics.

[0026] The thickness of the ceramic layer 23 is preferably about 0.3 to 20.0 mm. The ceramic layer 23 can be formed by various thermal spraying methods such as water plasma spraying or air plasma spraying, but may be formed by a method other than thermal spraying. Furthermore, the ceramic layer 23 may be formed by the same method as the base layer 22, or may be formed by a different method.

[0027] The base layer 22 and the ceramic layer 23 each penetrate into the porous metal body 21 through each pore of the porous metal body 21. At this time, the base layer 22 and the ceramic layer 23 do not need to penetrate into all the pores of the porous metal body 21, and it is preferable that they penetrate at least into the pores formed on the surface of the porous metal body 21 (the surface opposite to the metal component 1 side).

[0028] The heat-resistant coating material 2 is joined to the surface of the metal part 1 by any method. Examples of the joining method include mechanical joining, brazing, resistance welding, etc. After the heat-resistant coating material 2 is formed by laminating a base layer 22 and a ceramic layer 23 on the surface of a porous metal body 21, the heat-resistant coating material 2 may be joined to the surface of the metal part 1, or after the porous metal body 21 is joined to the surface of the metal part 1, the heat-resistant coating material 2 may be formed by laminating a base layer 22 and a ceramic layer 23 on the surface of the porous metal body 21.

[0029] In the heat-resistant component according to this embodiment, the porous metal body 21 with excellent flexibility can reduce thermal stress occurring between the metal component 1 and the ceramic layer 23. That is, even if the surface of the porous metal body 21 facing the metal component 1 shrinks as the metal component 1 thermally shrinks, the flexibility of the porous metal body 21 can suppress shrinkage of the surface of the porous metal body 21 opposite the metal component 1. As a result, the ceramic layer 23 covering the surface of the porous metal body 21 opposite the metal component 1 can be suppressed from peeling off from the metal component 1 in a high-temperature environment.

[0030] 2. Examples of heat-resistant coating materials 2 is a diagram for explaining an example of a heat-resistant coating material 2. This example shows the results of observing the appearance and cross section of each of the heat-resistant coating materials 2 produced using metal porous bodies A to E with different average pore sizes. The appearance was observed by visually inspecting the surface (upper surface) of the heat-resistant coating material 2, and the cross section was observed by visually inspecting the interface between each layer in the cross section of the heat-resistant coating material 2.

[0031] Celmet (registered trademark of Sumitomo Electric Industries, Ltd.) was used for the porous metal bodies A to E, and the surface was roughened by blasting with Al2O3, after which a base layer and a ceramic layer were laminated in sequence on both sides. The base layer was made of 80Ni-20Cr, and was spray-coated to a thickness of 0.2 mm by arc spraying on the surface of the porous metal bodies A to E. The ceramic layer was made of Al2O3, and was spray-coated to a thickness of 3 mm on the surface of the base layer by water plasma spraying.

[0032] The heat-resistant coating materials 2 formed as described above were heated in an electric furnace at a rate of 10°C / min, and were then heated and held at 1200 to 1300°C for 5 hours, after which they were cooled and their appearances and cross sections were observed. As a result, no peeling or damage occurred in the ceramic spray coating for any of the heat-resistant coating materials 2 using any of the metallic porous bodies A to E.

[0033] For comparison with heat-resistant coating material 2 using a porous metal body, a similar test was also conducted on a component in which a base layer and a ceramic layer were laminated in sequence by the above-mentioned method on the surface of a solid metal body without many pores on the surface or inside, rather than a porous metal body. In this case, the ceramic spray coating peeled off completely from the solid metal. This result shows that when a base layer and a ceramic layer are formed directly on the surface of the metal part 1, peeling of the ceramic layer from the metal part 1 cannot be suppressed in a high-temperature environment.

[0034] More specifically, in all of the porous metal bodies A to E having an average pore size of 0.5 to 3.2 mm, no peeling or damage occurred in the appearance or cross section, but when the average pore size exceeded 3.2 mm, the pores on the surface of the porous metal body could not be blocked unless the undercoat layer and ceramic layer were repeatedly coated multiple times. In other words, for porous metal bodies having an average pore size exceeding 3.2 mm, the thickness of the sprayed coating becomes too large by repeatedly coating multiple times, which is not preferable from the viewpoints of production cost and product weight.

[0035] On the other hand, when the average pore size is smaller than 0.5 mm, the condition is almost the same as when a solid metal is used, so it is difficult to suppress peeling of the ceramic layer in a high-temperature environment as described above. The porosity is preferably 80% or more.

[0036] Thus, the average pore size of the metal porous body is preferably 0.5 to 3.2 mm, and more preferably 0.6 to 1.9 mm. [Explanation of symbols]

[0037] 1 Metal parts 2. Heat-resistant coating materials 21 Metallic Porous Body 22 Base layer 23 Ceramic layer

Claims

1. A heat-resistant coating material for metal parts, comprising: A metal porous body provided on a surface of the metal part; and a ceramic layer covering the surface of the metal porous body.

2. 2. The heat-resistant coating material according to claim 1, wherein the average pore size of the porous metal body is 0.5 to 3.2 mm.

3. Further comprising a base layer formed on the surface of the metal porous body, The heat-resistant coating material according to claim 1 , wherein the ceramic layer covers a surface of the base layer.

4. The heat-resistant coating material according to claim 1 ; and a metal component having the heat-resistant coating material provided on a surface thereof.

5. A method for producing a heat-resistant coating material by spray-coating the surface of a porous metal body provided on the surface of a metal part with a ceramic layer.

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