JPS59141472A - Porous ceramic member surface minutening method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for surface densification of porous ceramic members.

In recent years, ceramic materials such as silicon carbide, silicon nitride, sialon, aluminum oxide, and zirconium oxide have attracted a lot of attention because of their excellent mechanical strength at high temperatures, as well as their excellent heat resistance and thermal shock resistance.
Numerous research and developments are underway for use in gas turbine rotors, diesel engine sills, and other high-temperature mechanical parts.

Among ceramics, porous ceramic members have excellent properties in terms of heat insulation, sound absorption, etc., and are expected to be used in a wide range of applications. By the way, porous ceramic members are usually fired by reducing the density of pressure molding of ceramic powder, or by adding a volatile or combustible substance during molding. Alternatively, it is manufactured by using a material that foams during the firing process, such as whitebait. However, the surface of conventional porous ceramics produced by these methods is also porous. Therefore, there are problems such as low wear resistance or low strength.

In order to solve these problems, it is possible to make the ceramic surface denser. However, CVD is a method for coating ceramic surfaces.

PVD, solvents, etc. have been proposed. However, CVD
Alternatively, the film formed by PvD is thin and requires a large amount of equipment and operation cost and time, and is insufficient to coat porous ceramic members. In addition, thermal spraying is a method in which a molten powder substance is sprayed onto the surface of a part, but it cannot fully fill the inside of the pores distributed on and near the surface of a porous ceramic member. There is a problem.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for densifying the surface of a ceramic member, which solves the problems of the prior art described above and can sufficiently densify the surface of a porous ceramic member. - In order to achieve this object, the present invention provides a porous ceramic member characterized in that a process is performed at least once on the surface of the porous ceramic member, in which ceramic powder is attached and then heated to bake the ceramic powder onto the surface of the ceramic member. The main purpose of this paper is a method for densifying the surface of high-quality ceramic members.

Further, the present invention is further characterized in that, if desired, the surface of the ceramic member onto which the ceramic powder has been baked is further smoothed.

The present invention will be explained in detail below.

The ceramic member to be surface-treated in the present invention is porous. This is because as the porosity decreases, typically
This is because as the diameter of the pores becomes smaller, the number of pores decreases, and the surface of the ceramic member can be made denser even by conventional methods. The method of the present invention is suitable for application to ceramics having a porosity of 15% or more, and is particularly suitable for densifying the surface of a porous ceramic member having a porosity of 25% or more.

The type of ceramic member is not particularly limited,
It can also be applied to oxides, nitrides, carbides, borides, or composites of these, such as aluminum oxide, zirconium oxide, silicon nitride, silicon carbide, lanthanum boride, zirconium boride, or Examples include Sialon.

In the present invention, any ceramic powder can be used as long as it is compatible with the ceramic member, but it is particularly preferable to use a powder having the same composition as the ceramic member.

The particle size of the ceramic powder is also influenced by the diameter of the bore of the ceramic member, but is usually 1 μm or less. In particular, if a superdifferential of 0 to 5ooX is used, it will be easy to print from a place with high reactivity, and it will be possible to fill even the smallest bores. Further, in the present invention, a sintering aid is added to the powder at a temperature higher than 0°C.

The ceramic powder can be attached to the surface of the ceramic member by suspending the powder in a solvent, applying this suspension to the surface of the ceramic member, and then evaporating the solvent. Alternatively, the ceramic powder can be applied to the surface of the ceramic member. It may also be sprinkled or sprayed.

In the present invention, various means can be employed as the heating means, for example, a heating furnace may be used, but by irradiating a laser, the desired position can be heated quickly and easily, and This is preferable because only the surface and its vicinity can be heated. Furthermore, when performing this laser irradiation, baking will be made easier if the surface to which the powder has been previously applied is baked at a temperature lower than the temperature.

The process of attaching ceramic powder to the surface of a ceramic member and baking this powder onto the ceramic member is carried out in 1
Although it may be repeated twice or more, a more dense and homogeneous surface can be obtained by repeating the process two or more times.

In addition, in the book 16, the surface of the ceramic member that has been coated with powder is further smoothed and the rock 1nJ?
It is also possible to set it to jt. Diamond grinding or diamond polishing 1 is a method for achieving this smooth finish.
．． c Which means can be adopted?

Hereinafter, the F implementation fFl-1 will be explained, but the present disclosure is not limited to the following embodiment unless it exceeds the gist thereof.

Example 1 The surface of a stabilized zirconium oxide plate with a porosity of 30% was treated according to the method of the present invention. I! did. First, average grain + i0.
81zm stabilized zirconium oxide powder
A suspension was prepared by dissolving it in alcohol, and this suspension was applied to the surface of a zirconium oxide plate. Sagibu volume ratio 21
After applying the 7σ suspension, evaporate the methyl alcohol, and then heat it at 200"C, then irradiate it with 17-ther in an argon atmosphere and heat it at 1700°C.
The zirconium oxide powder was baked onto the surface of the zirconium oxide plate by applying this powder and heating the surface. Burn this powder and process it! -! 'I repeated. In this way, the surface was densified and the porosity, thickness of the densified layer, bending strength and wear resistance were measured.

The results are shown in Table 1.

As in 17, the surface of the zirconium oxide plate was subjected to densification treatment 1-. Further, the surface of the treated zirconium oxide plate was polished and smoothed using diamond abrasive grains. Table 1 shows the results of measuring the characteristics of this smoothed zirconium oxide plate.

Table 1 (*) Surface abrasion resistance was determined by spraying steel powder particles 1 on the plate and determining the wear and tear caused by this 1'411.

From Table 1, the zirconium oxide plate according to the practical row is
It is recognized that the bending strength and lft abrasion resistance are superior to those before No. 11. It should be noted that the porosity values are approximately the same overall.

As described above, according to the method of the present invention, it is possible to sufficiently densify the surface on the porous ceramic part side. This also improves the strength and wear resistance of the porous ceramic portion.

3-

Claims (1)

[Claims] (11) A porous ceramic member characterized by applying a process of adhering ceramic powder to the surface of the porous ceramic member and then heating the ceramic powder to bake the ceramic powder onto the surface of the ceramic member at least once. (2) A method for surface densification of a porous ceramic member according to claim 1, characterized in that a process of baking ceramic powder onto the surface of the ceramic member is performed multiple times. ) A method for surface densification of a porous ceramic member according to claim 1 or 2, characterized in that after adhering the ceramic powder, the ceramic powder is baked to a temperature of 4 and heated by irradiating with a laser. ) The ceramic powder is stuck onto the surface of the porous ceramic member and then heated to bake the ceramic powder onto the surface of the ceramic member at least 61 times, and then the surface is smoothed and finished. A method for surface densification of porous ceramic members.