JPH07258816A - Ceramic coating structure on metallic base material and its formation - Google Patents

Abstract

PURPOSE:To provide a metallic base material with a ceramic coating structure combining thermal stress relaxation and oxidation resistance only by a single layer, free from cracking and peeling, and excellent in durability and to form such a ceramic coating structure with high efficiency. CONSTITUTION:This coating structure is constituted by continuously changing, in a thickness direction, the composition ratio between metal 2 and ceramic 3, both constituting a coating layer 5, so that the proportion of the ceramic 3 increases from the interface between the layer and a metallic base material 1 toward the surface of the layer and also dispersing superfine grains 4 of a second ceramics in the metal. Further, such a structure can be formed by preparing a powder material, where the grains of the second ceramics are superfinely dispersed in the metal, and a ceramic powder, mixing these powders while changing mixing ratio so that the proportion of the ceramic powder increases along the thickness direction, laminating the resulting powder mixture on the metallic base material, and then applying sintering.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic coating structure on a metal substrate and a method for forming the same. More specifically, the physical properties (physical properties) of the material and the required function are separated from each other. The structure of a ceramic coating on a metal substrate having both thermal stress relaxation characteristics depending on physical properties and surface functions such as corrosion resistance and abrasion resistance, and a method for forming such a coating structure. It is about.

[0002]

2. Description of the Related Art In recent years, in order to improve functions such as heat resistance, corrosion resistance and abrasion resistance, ceramic coating on a metal base material has been actively carried out, and its application fields are also diverse. However, when the ceramic is coated, cracks and peeling easily occur in the ceramic coating at the time of production and use, which is the biggest problem. Such cracking and peeling are very fragile, which is the inherent property of ceramic materials, and the physical properties (physical properties) of metals and ceramics such as coefficient of thermal expansion, thermal conductivity, Young's modulus, and Poisson's ratio. The thermal stress caused by the difference is a major cause, and not only the effect of coating the ceramic cannot be fully utilized, but it often causes a trouble during use. In particular, when a material in which a metal base material is coated with ceramic is used in a high temperature oxidizing atmosphere or the like, cracking or peeling of the ceramic coating is likely to occur for the following reasons, which can be said to be a very severe condition for the coating material. That is, in a high temperature oxidizing atmosphere, a thermal stress is generated due to a difference in coefficient of thermal expansion between the metal base material and the ceramic coating, and at the same time, a material change occurs in the metal base material or the ceramic coating such as generation of an oxide. This is because the strength and adhesion of the coating are reduced.

Conventionally, in order to prevent cracking and peeling of the ceramic coating and improve reliability, in a coating structure in which different materials such as metal and ceramic are joined,
Various attempts have been made to alleviate thermal stress and improve oxidation resistance. That is, first, as an attempt to reduce the thermal stress due to the difference in the coefficient of thermal expansion, the invention described in JP-A-4-214826 (method for producing composite material and composite material, method for producing heat receiving material and heat receiving material) ), And the invention (method for producing functionally gradient material) described in Japanese Patent Application No. 3-110595. In each of these, by continuously changing the composition at the interface of the two materials,
It aims to reduce thermal stress by eliminating the parts where the material properties such as thermal expansion coefficient and Young's modulus change rapidly.
The present invention relates to a method for producing a functionally graded material in which the function at the interface between different materials is continuously changed.

Among these, the invention described in Japanese Patent Application Laid-Open No. 4-214826 is one in which a low melting point metal is infiltrated into the pores after producing a high melting point metal whose porosity is continuously changed. , A functionally graded material is manufactured.
Further, the invention described in Japanese Patent Application No. 3-110595 discloses that a graded composition block is produced by using a method such as a sintering method or a thermal spraying method, in which graded composition can be relatively easily performed, and then extrusion, drawing, The present invention relates to a method for producing a functionally gradient material having a long dimension, which is finished into an arbitrary shape by plastic working such as rolling.

On the other hand, as an attempt to reduce the decrease in adhesion between the metal base material and the ceramic coating film due to the generation of oxides, the invention described in Japanese Patent Application Laid-Open No. 3-20451 (ceramic-coated gas turbine blade). There is. This is intended to suppress the formation of oxide by providing an alloy layer for oxidation resistance under the ceramic coating film on the surface. At least one of Co and Ni, Cr and Al, and further Hf, Ta, Y and S are used as materials for forming such an alloy layer.
An alloy excellent in oxidation resistance containing at least one element of i and Zr is defined.

From another point of view, there is also an attempt to reduce the cracking and peeling of the ceramic coating film on the metal substrate to improve the durability. That is, Japanese Patent Application No. 4-
The method of ceramic coating on a metal substrate described in Japanese Patent No. 214422 discloses a method in which a material formed by gradually changing the composition from metal to ceramic is subjected to heat treatment,
By applying an arbitrary compressive residual stress to the ceramic coating, the ceramic coating is strengthened and the adhesion to the substrate is improved.

[0007]

As described above, in ceramic coating materials used under severe conditions such as a high temperature oxidizing atmosphere, various attempts have been made to prevent cracking and peeling of the ceramic coating. . Summarizing these efforts, we can roughly divide them into structural improvement and material improvement. Of these, structural improvements are mainly aimed at relaxing thermal stress by graded composition, etc., and material improvements aim at improving deterioration characteristics over time such as the addition of oxidation resistant layers. There are many. However, in the conventional improvement measures, those for the purpose of only relaxing the thermal stress, those for the purpose of only improving the oxidation resistance, or the thermal stress relaxation and the oxidation resistance are carried by different layers. Although there are various types of materials, it is the current situation that one layer that has both thermal stress relaxation and oxidation resistance is not yet known.

The present invention has been made to solve the above problems, and has a material for controlling the physical properties of the material that causes the generation of thermal stress and another surface function such as oxidation resistance. By including a material, it is possible to combine thermal stress relaxation and oxidation resistance in one layer to provide a ceramic coating structure on a metal substrate that is excellent in durability without cracking or peeling, and It is an object to provide a method of efficiently forming a ceramic coating structure.

[0009]

A ceramic coating structure for a metal base material of the present invention is a ceramic coating structure in which a coating layer mainly composed of ceramic is provided on a metal base material, and the metal forming the coating layer is The composition ratio with the ceramic is continuously changed in the thickness direction so that the ratio of the ceramic increases from the interface with the metal substrate toward the surface of the coating layer, and in the metal of the gradient composition region. In addition, ultrafine particles of the second ceramic are dispersed.

The method for forming a ceramic coating structure on a metal substrate according to the present invention is a method of forming a coating layer mainly composed of ceramics on a metal substrate, wherein ultrafine particles of the second ceramic are formed in the metal. The dispersed powder material and the ceramic powder are respectively prepared, and the metal base material is mixed while changing the mixing ratio so that the ratio of the ceramic powder increases along the thickness direction. It is characterized in that after it is laminated on top, it is sintered.

A second method of forming a ceramic coating structure of the present invention is a method of forming a coating layer mainly composed of ceramics on a metal substrate, wherein ultrafine particles of the second ceramic are formed in the metal. The dispersed powder material and the ceramic powder are respectively prepared, and these powders are respectively supplied into a high temperature flame while changing the supply ratio so that the ratio of the ceramic powder increases with time, The method is characterized in that a heat treatment is performed after plasma spraying on the metal base material.

Furthermore, a third method of forming a ceramic coating structure of the present invention is a method of forming a coating layer mainly composed of ceramics on a metal substrate, wherein ultrafine particles of the second ceramic are contained in the metal. The dispersed powder material and the ceramic powder were respectively prepared, and these powders were mixed at different mixing ratios and then sintered to manufacture a plurality of thin plates having different composition ratios of the metal and the ceramic. After that, these thin plates are laminated in order of increasing composition ratio of the ceramic, and heated under pressure to be integrally molded.

In the ceramic coating structure for a metal substrate and the method for forming the same according to the present invention, the second ceramic is a hard and chemically stable oxide system such as Al ₂ O ₃ or Y ₂ O _3. It is desirable to use a ceramic and an ultrafine powder having a particle size of 0.1 μm or less. Further, the content of such a second ceramic is preferably 0.5 to 10.0% by weight of the matrix metal to be dispersed. The second ceramic content is 0.5
If it is less than 10% by weight, the effect of improving the oxidation resistance of the ceramic coating layer is not sufficient, and 10.0% by weight
If it exceeds, the physical properties, particularly toughness, are extremely deteriorated, which is not preferable.

Furthermore, in the first, second and third methods of forming a ceramic coating structure on a metal substrate of the present invention, in order to disperse the above-mentioned ultrafine second ceramic particles in the metal, It is desirable to employ a so-called mechanical alloy method in which the powder of No. 1 and the powder of the second ceramic are mixed while being crushed by strong mechanical energy.

[0015]

In the ceramic coating structure for a metal substrate of the present invention, the composition ratio of the metal and the ceramic constituting the coating layer is continuously changed in the thickness direction,
And since the composition ratio of the ceramic is formed so as to gradually increase from the interface with the metal substrate toward the surface,
The physical properties such as the coefficient of thermal expansion and Young's modulus of the coating layer continuously change in the thickness direction, and the rapid change of the physical properties disappears. Therefore, the thermal stress caused by the difference in thermal expansion is relaxed. Further, in such a gradient composition region,
Since the ultrafine particles of the second ceramic are dispersed in the metal, which is one of the constituents, the function of the hard and chemically stable second ceramic particles is added without changing the physical properties of the material, and corrosion resistance is improved. And functions such as abrasion resistance are improved.

In the method for forming the ceramic coating structure of the present invention, the powder material in which the particles of the second ceramic are ultrafinely dispersed in the metal and the powder of the first ceramic are prepared by a mechanical alloy method or the like. The metal and the first ceramic can be made to have a graded composition by laminating on a metal base material while mixing while gradually changing the mixing ratio, and the metal can be made to have a graded composition. It is possible to form a coating layer in which the second ceramic is ultrafinely dispersed.

In the second method of forming the ceramic coating structure of the present invention, the metal powder material in which the second ceramic particles are ultrafinely dispersed and the first ceramic powder are formed in the same manner as the above method. , While supplying each other in the high temperature frame while changing the mutual supply ratio,
By spraying the material thus melted at a high flow rate onto a metal base material (plasma spraying) and then performing a heat treatment, the metal and the first ceramic are made to have a graded composition, and the metal is formed in such a graded composition region. It is possible to form a coating layer in which the second ceramic is ultrafinely dispersed.

Further, in the third forming method of the present invention, the metal powder material in which the second ceramic particles are ultrafinely dispersed and the first ceramic powder are mixed and sintered at different mixing ratios. By laminating a plurality of thin plates having different composition ratios obtained in this order, pressurizing and heating to form and integrate them, the metal and the first ceramic are made to have a graded composition, and such a graded composition region. Thus, it is possible to form a coating layer in which the second ceramic is ultrafinely dispersed in the metal.

Furthermore, in the method for forming a ceramic coating structure of the present invention, after forming a coating layer on a metal substrate by the above-mentioned sintering method or plasma spraying method, heat treatment is performed in a vacuum or a pressurized atmosphere. By performing or by performing hot plastic working such as rolling or extrusion, the coating layer itself can be further sintered, and at the same time, the elements constituting the coating layer and the elements constituting the metal base material. Mutual diffusion can be caused. Therefore, by such heat treatment or plastic working, the strength of the coating layer itself is improved and the adhesion between the metal base material and the coating layer is improved.

[0020]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view schematically showing an embodiment of a ceramic coating structure for a metal substrate according to the present invention. In this figure, reference numeral 1 indicates, for example, Ni or C.
Heat resistant alloy based on o or Fe (MCrAlY)
The base material is shown on top of which the heat-resistant alloy MCrAl
Y2 and ZrO ₂ -8 wt% which is a ceramic with low thermal conductivity
Y ₂ O ₃ 3 and Al ₂ O ₃ which is the second ceramic
A coating layer 5 consisting of 4 as described below is provided. That is, this ceramic coating layer 5
Has a composition ratio of MCrAlY2 of 100% on the heat-resistant alloy substrate 1, and ZrO ₂ -8 on the surface of the coating layer 5.
From the top of the heat-resistant alloy substrate 1 to the surface of the coating layer 5, MCr so that the composition ratio of wt% Y ₂ O ₃ becomes 100%.
The composition ratio of AlY2 and ZrO ₂ -8 wt% Y ₂ O ₃ 3 is continuously changed in the thickness direction. By doing so, as shown in FIG. rate,
The physical properties of the material such as the Poisson's ratio are controlled so as not to change suddenly, and the thermal stress at the time of manufacturing and use is relaxed. In addition, the coating layer 5 of MCrAlY2 and ZrO
_In the region where 2-8 wt% Y ₂ O ₃ 3 is graded, the ultrafine particles of the second ceramic Al ₂ O _{3 in} the matrix of MCrAlY 2 are 0.5-10.
It is contained and dispersed in a proportion of 0% by weight, and due to such dispersion, as shown in FIG. 2B, surface functions such as oxidation resistance and abrasion resistance are remarkably added.

The operation of this embodiment will be described in detail below with reference to FIGS.

In the ceramic coating layer of the example, the composition ratio of MCrAlY and ZrO ₂ -8 wt% Y ₂ O ₃ was continuously changed in the thickness direction, and such MCrAlY and ZrO ₂ -8 wt%. Y ₂ O ₃ is used as a particle to control the physical properties such as linear expansion coefficient and Young's modulus, and the portion where the physical properties change rapidly (discontinuously) is eliminated, so thermal stress during manufacturing and use Has been eased. Further, in the examples, since the physical properties are continuously changed, it is necessary to eliminate the stress singular points (singular points of the stress in the plate thickness direction and the shear stress) generated at the ends when the physical properties are discontinuously changed. You can

FIG. 3 shows the ceramic coating structure of the embodiment and the conventional coating structure (MCrAlY and ZrO.
₂ shows the measurement results of the thermal stress in the direction parallel to the plate thickness during heating for a two-layer body in which a coating layer of 2-8 wt% Y ₂ O ₃ 100% was directly provided). As can be seen from this graph, the conventional coating structure
In contrast to the large thermal stress at the interface between the metal base material and the ceramic coating layer, in the coating structure of the embodiment, the thermal stress is maximum on the surface of the coating layer and the back surface of the base material. Are different. Also,
Comparing the two with the maximum value, the absolute value of the coating structure of the embodiment is overwhelmingly smaller than that of the conventional structure.

The now to consider the functions of the embodiment, and a second ceramic A1 ₂ 0 ₃ of ultrafine particles is dispersed in MCrAlY matrix is heat-resistant alloy,
The finely dispersed Al ₂ O ₃ particles effectively act to suppress and stabilize the growth of oxide films such as Al ₂ O ₃ and Cr ₂ O _{3 on the} surface of MCrAlY, so that the oxidation resistance is significantly improved. 4, taken on the vertical axis the oxidation weight gain as a parameter representative of the oxidation resistance, in which examine changes in oxidation weight gain relative to the addition amount of A1 ₂ 0 ₃ (content). As is apparent from this graph, by ultrafine dispersing A1 ₂ 0 ₃ particles into the MCrAlY, oxidation resistance is greatly improved.
Further, FIG. 5 shows that 0.5 to 1 of Al ₂ O ₃ was added to MCrAlY.
With respect to the ceramic coating layer of the example in which it is ultrafinely dispersed at a ratio of 0.0% and the conventional ceramic coating layer containing no Al ₂ O ₃ , the time variation of the oxidation weight increase in a high temperature oxidizing atmosphere is shown. is there. From this graph, in the coating layer of the example, the oxidation weight gain in the high temperature oxidizing atmosphere is significantly reduced as compared with the conventional one, and the oxidation resistance which is the biggest problem of the ceramic which is the oxygen ion permeable material is It can be seen that is greatly improved.

Further, the ceramic coating structure of the example and various conventional coating structures were repeatedly subjected to a thermal cycle of 1100-200 ° C. and 2 Hr holding in the atmosphere (thermal cycle test), and the results are shown in FIG. Are shown respectively. As is clear from this graph, the ceramic coating structures of the examples have excellent heat cycle characteristics, and show excellent durability with little cracking or peeling during repeated use in a high temperature oxidizing atmosphere.

Next, a method for forming such a ceramic coating structure on a metal substrate will be described.

In the first method (sintering method), as shown in FIG. 7 (a), first, MCrAlY powder and Al ₂ O ₃ powder are used as raw materials and pulverized and mixed by a mechanical alloy method to form an MCrAlY matrix 6 A dispersion powder (powder A) 8 in which ultrafine particles 7 of Al ₂ O ₃ are dispersed is prepared. On the other hand, ZrO
Of _{2 -8wt%} Y ₂ O ₃ powder (powder B) is prepared. Then, as shown in FIG. 7 (b), the powder A8 and ZrO ₂
-8 wt% Y ₂ O ₃ powder (powder B) 9 is uniformly mixed by a ball mill or the like. At this time, powder A8 and powder B
Several kinds of mixed powders having different mixing ratios with 9 are prepared.
Then, as shown in FIG. 7 (c), a mixed powder layer 11 is laminated on the metal base material 10 such as MCrAlY by using the mixed powders in order of the ratio of MCrAlY being larger, and then, as shown in FIG. As shown in (d), the powder layer 11 thus laminated is subjected to uniaxial molding by a mold or normal temperature isotropic pressure (CIP) molding to densify the powder. Finally, as shown in FIG. 7 (e), the formed powder layer 11 is sintered in a heating furnace 12 such as an electric furnace to improve the strength of the coating layer, and the coating layer and the metal substrate 1
The adhesion is improved by mutual diffusion of elements with 0.
In this way, the ceramic coating structure on the metal substrate of the above embodiment can be easily formed. In such a sintering method, it is possible to simultaneously perform densification and sintering of the powder by CIP molding or the like in one step such as sintering while applying pressure. That is, the laminated powder layer 11 can be formed by a hot press sintering method, a hot isotropic pressing method (HIP), or the like.

Next, another method for forming the ceramic coating structure of the embodiment will be described.

That is, in the second method, as shown in FIG.
As shown in, as in the example, by mechanical alloying of MCrAlY powder and Al ₂ O ₃ powder as raw material, Al ₂ O during MCrAlY matrix 6
While preparing a dispersion powder (powder A) 8 in which the ultrafine particles ₃ of ₃ are dispersed, Z is prepared by an electrofusion pulverization method or a chemical deposition method.
A powder (powder B) 9 of rO ₂ -8 wt% Y ₂ O ₃ is prepared. Then, as shown in FIG. 8 (b), hard particles 13 such as Al ₂ O ₃ particles are jetted at high speed onto the surface of the metal base material 10 such as MCrAlY to roughen the surface of the base material 10 (blast treatment). To do. Then, the surface of the metal substrate 10 is cleaned. That is, as shown in FIG. 8C, the oxide on the surface of the base material is removed by the transferred arc 14 in which the base material 10 is used as a positive electrode in a non-oxidizing atmosphere. Next, as shown in FIG. 8D, particles obtained by melting the powder A and the powder B by the plasma spraying method are made to collide with the surface of the metal substrate 10 at high speed as the plasma jet 15. At this time, the ratio of the powder A and the powder B is changed and supplied into the high temperature flame so that the supply ratio of the powder B increases with time. Finally, as shown in FIG. 8 (e), the coating film 16 formed by thermal spraying is subjected to a heat treatment in a vacuum or in an inert gas atmosphere in order to densify and improve the adhesion with the substrate. .

Further, in the third method, as shown in FIG.
As shown in FIG. 5, a mechanical alloying method is used to prepare a dispersion powder (powder A) 8 in which ultrafine particles ₂ of Al ₂ O ₃ are dispersed in an MCrAlY matrix 6 as in the above-described embodiment, while an electro-melting method is used. ZrO ₂
After preparing a powder (powder B) 9 of −8 wt% Y ₂ O ₃ , these powders are uniformly mixed by a ball mill or the like as shown in FIG. 9 (b). At this time, several kinds of mixed powders having different mixing ratios of the powder A and the powder B are prepared. Then, FIG.
As shown in (c), using these mixed powders, several kinds of thin plates 17 having different composition ratios of powder A and powder B are produced by a sintering method or the like. Then, as shown in FIG. 9 (d), these thin plates 17 are laminated in the descending order of composition ratio of MCrAlY, and then as shown in FIG.
Canning in 8. Then, the laminated plate 19 thus canned is subjected to a treatment in a high-temperature pressurized atmosphere, that is, a HIP treatment to be integrated. Finally, the integrated laminated plate 19 is taken out from the canning container 18 and, at the same time, is machined to a predetermined size for finishing.

In the ceramic coating structure on the metal substrate formed by the first, second and third methods described above, MCrAlY and zr _O2 -8wt from the interface with the metal substrate to the surface of the coating layer. % Y ₂ 0 ₃ of which are gradually changed along the thickness direction composition ratio, since the physical properties such as coefficient of linear expansion and Young's modulus are controlled, thermal stress generated during heating such as during manufacture or use Is alleviated.

Further, in this way, MCrAlY and ZrO ₂
In the gradient composition region of the coating layer in which the composition ratio of −8 wt% Y ₂ O ₃ is continuously changed, ultrafine Al ₂ O ₃ particles are dispersed in the matrix of MCrAlY. The oxidation resistance is improved with almost no change in the physical properties such as the rate, and it also has excellent heat cycle characteristics and has excellent durability in a high temperature oxidizing atmosphere.

[0034]

As is apparent from the above description, according to the ceramic coating structure for a metal substrate of the present invention,
Controlling physical properties of materials such as linear expansion coefficient and Young's modulus that cause thermal stress and functions such as oxidation resistance are provided in different materials, so that one coating layer relaxes thermal stress and oxidation resistance. It is possible to combine desired functions such as. Therefore, a ceramic coating layer having excellent durability can be obtained without cracking or peeling even in a high temperature oxidizing atmosphere.

Further, according to the method of the present invention, a ceramic coating layer having such excellent physical properties and functions and excellent durability can be easily and stably formed.

[Brief description of drawings]

FIG. 1 is a cross-sectional view schematically showing an example of a ceramic coating structure for a metal substrate according to the present invention.

FIG. 2 is a graph schematically showing the relationship between the thickness position of the coating layer and the physical properties and functions in the same example.

FIG. 3 is a graph showing measurement results of thermal stress parallel to the plate thickness during heating for the ceramic coating structure of the example and the conventional coating structure.

FIG. 4 is a graph schematically showing a change in the amount of oxidation increase with respect to the amount of Al ₂ O ₃ added to MCrAlY.

FIG. 5 is a graph showing changes over time in the amount of oxidation increase in a high temperature oxidizing atmosphere for the coating layer of the example and the conventional ceramic coating layer not containing Al ₂ O ₃ .

FIG. 6 is a graph showing the results of a thermal cycle test in the atmosphere for the coating structure of the example and various conventional coating structures.

FIG. 7 is a diagram schematically showing each step in one embodiment (sintering method) of the method for forming a ceramic coating structure of the present invention.

FIG. 8 is a diagram schematically showing each step in the second embodiment (plasma spraying method) of the method for forming a ceramic coating structure of the present invention.

FIG. 9 is a diagram schematically showing each step in the third embodiment (method of integrating thin plates by HIP) of the method for forming a ceramic coating structure of the present invention.

[Explanation of symbols]

1 ... Heat resistant alloy (MCrAlY) substrate 2 ... MCrAlY 3 ... ZrO ₂ -8 wt% Y ₂ O ₃ 4 Al ₂ O ₃ 5 coating layer 8 Dispersed powder ( Powder A) 9 ... ZrO ₂ -8 wt% Y ₂ O ₃ powder (powder B) 10 ... Metal substrate 11 ... Mixed powder layer 15 Plasma jet 16 Thin plate

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takanari Okamura 4-4 Suehiro-cho, Tsurumi-ku, Yokohama-shi, Kanagawa Stock company Toshiba Keihin office

Claims (7)

[Claims] 1. In a ceramic coating structure in which a coating layer composed mainly of ceramic is provided on a metal substrate, the composition ratio of the metal and the ceramic constituting the coating layer is set such that the ratio of the ceramic to the metal substrate is Continuously changing in the thickness direction so as to increase from the interface toward the surface of the coating layer, and superfine particles of the second ceramic are dispersed in the metal of the gradient composition region. A ceramic coating structure on a metal substrate characterized by: 2. The second ceramic is a hard and chemically stable oxide ceramic and has a grain size of 0.1.
If the particle size is less than μm, the content of metal is 0.5-10.0% by weight.
A ceramic coating structure on a metal substrate according to claim 1. 3. A method of forming a ceramic-based coating layer on a metal substrate, wherein a powder material in which ultrafine particles of a second ceramic are dispersed in a metal and a powder of the ceramic are prepared respectively. Then
These metal powders are laminated on the metal base material while mixing while changing the mixing ratio so that the ratio of the ceramic powder increases along the thickness direction, and then sintered. Method for forming ceramic coating structure on wood. 4. A method for forming a ceramic-based coating layer on a metal substrate, wherein a powder material in which ultrafine particles of a second ceramic are dispersed in a metal, and a powder of said ceramic are prepared, respectively. Then
These powders are respectively supplied into the high temperature flame by changing the supply ratio so that the ratio of the ceramic powder increases with time, plasma-sprayed on the metal base material, and then heat treatment is performed. A method of forming a ceramic coating structure on a featured metal substrate. 5. A method for forming a ceramic-based coating layer on a metal substrate, wherein a powder material in which ultrafine particles of a second ceramic are dispersed in a metal, and a powder of said ceramic are prepared, respectively. Then
These powders are mixed in different mixing ratios and then sintered to produce a plurality of thin plates having different composition ratios of the metal and the ceramic, and then these thin plates are laminated in order of increasing composition ratio of the ceramics. A method for forming a ceramic coating structure on a metal substrate, which comprises heating under pressure and integrally molding. 6. The second ceramic is a hard and chemically stable oxide ceramic and has a grain size of 0.1.
If the particle size is less than μm, the content of metal is 0.5-10.0% by weight.
The method for forming a ceramic coating structure on a metal substrate according to any one of claims 3 to 5. 7. A powder material in which ultrafine particles of a second ceramic are dispersed in a metal, wherein the powder of the metal and the powder of the second ceramic are prepared by a mechanical alloy method. Item 7. A method for forming a ceramic coating structure on a metal substrate according to any one of items 3 to 6.