JPH05238855A - Production of ceramic coating member - Google Patents

Abstract

PURPOSE:To provide a method of producing a ceramic coating member having good adhesion between a ceramic substrate and the coating layer, excellent high-temperature strength and heat resistance and good oxidation resistance and corrosion resistance and high in reliability. CONSTITUTION:The surface of a ceramic substrate consisting of a material selected from silicon carbide, silicon nitride or a silicon carbide-dispersed and strengthened silicon nitride composite material is subjected to mechanical processing, heat-treatment or chemical treatment so that ten point average roughness (Rz) as surface roughness may be >=1.5mum and average roughness of center line (Ra) may be >=0.2mum and then at least one kind of material selected from alumina, mullite, zircon, zirconia and yttria is subjected to plasma spray coating onto the surface of the substrate so as to give >=50mum thickness of a ceramic coating layer to provide the objective ceramic coating member.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a ceramic coating member.

[0002]

2. Description of the Related Art Conventionally, ceramic materials such as silicon carbide and silicon nitride have been known as high temperature structural materials used under high temperature and severe conditions.

[0003]

However, even with such high-temperature heat-resistant materials such as silicon carbide or silicon nitride, when these materials are exposed to combustion gas having a high flow velocity, they are subject to high-temperature oxidation, high-temperature corrosion, etc. Parts are often thinned. For this reason, regarding the members exposed to the combustion gas having a high flow velocity, the most important issue is to improve the oxidation resistance in order to improve the durability.

To solve this problem, a method of coating the surface of the base material of the high temperature heat resistant material with oxide ceramics has been proposed. According to this method, however, the oxide ceramics cannot be coated depending on the surface condition of the base material. Even if it can be coated, it may peel off in a short time when used at high temperature. An object of the present invention is to provide a method for producing a highly reliable ceramic coating member, which has good adhesion between a ceramic base material and a coating layer, excellent high-temperature strength and heat resistance, good oxidation resistance, and good corrosion resistance. It is in.

[0005]

In order to achieve the above object, a method of manufacturing a ceramic coating member according to the present invention comprises selecting a base material from silicon carbide, silicon nitride or a silicon carbide dispersion strengthened silicon nitride composite material. The surface of the base material is machined, heat-treated or chemically treated so that the ten-point average roughness (symbol Rz) is 1.5 μm or more and the center line average roughness (symbol Ra) is 0.2 μm or more. It is characterized in that at least one selected from alumina, mullite, zircon, zirconia, and yttria is plasma sprayed on the surface of the substrate after the treatment.

The ten-point average roughness (symbol Rz) is 1.5 μm.
It is less than these values that the center line average roughness (symbol Ra) is 0.2 μm or more.
This is because it becomes difficult to coat the surface of the substrate with alumina, mullite, zircon, zirconia, or yttria firmly and with good durability. The layer thickness of the ceramic coating layer obtained by plasma spraying is preferably 50 μm or more. The layer thickness of the ceramic coating layer is set to 50 μm or more because it is used for a long time when the layer thickness of the ceramic coating layer is less than 50 μm under severe use conditions such as contact with high-speed combustion gas. This is because there is a problem in reliability.

[0007]

According to the method for manufacturing a ceramic coating member of the present invention, the surface of a ceramic base material before coating is made to have an appropriate surface roughness, and a coating layer formed by plasma spraying is formed on the surface of the roughened base material. As a result, the adhesion between the ceramic base material and the coating material becomes good, and a highly reliable ceramic coating member can be manufactured.

[0008]

EXAMPLES Examples of the present invention will be described below. B ₄ C,
Silicon carbide sintered bodies containing C as an additive (Examples 1 to 5 and Comparative Examples 1 to 5) and silicon nitride sintered bodies containing Y ₂ O ₃ and Yb ₂ O ₃ as additives (Examples 6 to 10). Comparative Examples 6 to 10), and a composite sintered body containing silicon nitride containing Y ₂ O ₃ and Yb ₂ O ₃ as a base material and silicon carbide particles or whiskers as a reinforcing material (Examples 11 to 15). Comparative Examples 11 to 1
Using 5) as the substrate, the substrate surface roughness and the adhesion of the oxide coating layer were examined. Width of test piece is 4mm and height is 3m
m, length 40 mm.

Details are shown in Table 1 below.

[0010]

[Table 1] In Table 1, Examples 1 to 5 are 1 at a temperature of 1400 ° C. in the atmosphere.
Heat treatment was performed for 0 hours. In Examples 6 to 10, etching treatment was performed in HF at 70 ° C. for 1 hour. Examples 11 to
Sample No. 15 was sandblasted with mixed abrasive grains of 50 wt% of # 36 silicon carbide abrasive grains and 50 wt% of # 36 alumina abrasive grains.

The base material of Comparative Examples 1 to 5 is a machined surface made of silicon carbide and machined with a # 140 diamond grindstone. The base materials of Comparative Examples 6 to 10 were processed with silicon nitride and then heat-treated in the atmosphere at a temperature of 1300 ° C. for 1 hour. Comparative Example 1
The base materials 1 to 15 are processed with the composite material, and the temperature is 130 in the air.
Heat treatment was performed at 0 ° C. for 1 hour. About 10 layers of oxide coating layers of alumina, mullite, zircon, zirconia, and yttria are added to the base materials of Examples 1 to 15 and Comparative Examples 1 to 15.
It was formed by plasma spraying so as to have a thickness of 0 μm. The adhesion state of the oxide coating layer formed by plasma spraying and the heat cycle characteristics by repeated heating and cooling between room temperature and 1400 ° C. were measured and evaluated. The results are shown in Table 1.

Coating Test (Evaluation of Oxide Covering State) In Table 1, the adhesion state of the coating layer was evaluated by visually observing whether or not the surface of the substrate was uniformly covered with the oxide coating layer. As a result, in Examples 1 to 15 and Comparative Examples 6 to 15, the adhered state of the oxide coating layer was good. In Comparative Examples 1 to 5, the oxide coating layer was attached only to a part of the base material and could not be coated. It has been revealed that it is difficult to coat the oxide when the surface roughness of the substrate is fine.

Load Test (Heat Resistance Cycle Evaluation) The adhesion between the base material and the oxide coating is subjected to a heat resistance cycle by repeating heating and cooling between room temperature and 1400 ° C., and the base material is observed with an optical microscope for each cycle. And the coating layer interface was observed. As a result, in Examples 1 to 15, peeling did not occur at the interface between the base material and the coating layer even when the heating and cooling were repeated 20 times between room temperature and 1400 ° C. Comparative Examples 6 to 15 have room temperature and 1
Peeling occurred at the interface between the base material and the coating layer by repeating heating and cooling once at 400 ° C. It has been clarified that the surface roughness of the substrate cannot withstand the heat cycle unless the surface roughness is appropriate.

[0014]

As described above, according to the method for producing a ceramic coating member of the present invention, the surface of the ceramic substrate is made to have an appropriate surface roughness, and the surface of the substrate is alumina, mullite or zircon by plasma spraying. , Zirconia,
Since at least one type of coating layer selected from yttria is formed, the adhesion between the ceramic base material and the oxide coating layer and the heat cycle characteristics are improved, so that it can withstand high temperatures sufficiently and oxidize at high temperatures. There is an effect that a highly reliable ceramic coating member having good corrosiveness can be manufactured.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tomonori Takahashi 151 Kitahata, Shinmaiko, Chita City, Aichi Prefecture (72) Inventor Hiromichi Kobayashi 1-11 Ukihashi, Yokkaichi City, Mie Prefecture

Claims (2)

[Claims] 1. A material of a base material is selected from silicon carbide, silicon nitride or a silicon carbide dispersion strengthened silicon nitride composite material and has a ten-point average roughness (symbol Rz) of 1.5 μm or more as a surface roughness and a center line. The surface of the base material is machined, heat-treated or chemically treated so that the average roughness (symbol Ra) becomes 0.2 μm or more, and then the surface of the base material is selected from alumina, mullite, zircon, zirconia and yttria. A method for manufacturing a ceramic coating member, which comprises plasma spraying at least one kind. 2. The method for producing a ceramic coating member according to claim 1, wherein the thickness of the ceramic coating layer obtained by the plasma spraying is 50 μm or more.