JPS621503A - Manufacture of ceramic sintered body - 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 [Industrial Field of Application] The present invention relates to a method of manufacturing a ceramic sintered body, and relates to a method of manufacturing a ceramic component such as a turbo rotor.

[Conventional technology]

In recent years, ceramic materials are being considered for application to various parts by taking advantage of their excellent heat resistance and wear resistance. As one of these, ceramic materials are used as high-efficiency gas turbine materials, and methods of integrally manufacturing turbo rotors and the like using ceramic materials are being considered.

One method for manufacturing ceramic sintered bodies such as turbo rotors is injection molding. In this method, a kneaded mixture of ceramic powder and an organic binder is molded into a predetermined shape in a mold by injection molding, making use of the plasticity of the organic binder. Ceramic sintered bodies are obtained by firing the decomposed and removed (degreased) material.

[Problem that the invention seeks to solve]

By the way, during the above-mentioned injection molding, metal fine powder adheres to the surface of the injection molded product due to friction with the mold.

The metal fine powder adhering to the surface of the injection molded body may remain as foreign matter in the ceramic sintered body after firing, or it may roughen the surface and worsen the surface condition, resulting in deterioration of the surface quality of the ceramic sintered body. .

Therefore, in the method of manufacturing a ceramic sintered body, it has been desired to remove such foreign substances such as fine metal powder.

[Means for solving problems]

The above problem is solved by the method for manufacturing a ceramic sintered body of the present invention, which will be described below.

That is, the method for manufacturing a ceramic sintered body of the present invention involves injection molding a mixed powder of ceramic powder and a sintering aid into a predetermined shape using an organic binder, degreasing the obtained injection molded body, A method for producing a fired ceramic sintered body, characterized in that after the injection molding, a surface cleaning treatment is performed to clean the surface of the injection molded body.

In the present invention, the surface cleaning treatment is performed by immersing the ceramic injection molded body in an acid such as hydrochloric acid, nitric acid, sulfuric acid, or hydrofluoric acid. At this time, the treatment temperature is preferably from room temperature to 100° C., and the treatment time is preferably about 1 to 10 minutes. After soaking with these acids, the acids are removed by washing with water.

[Effect]

According to the method for producing a ceramic sintered body of the present invention, foreign matter such as fine metal powder adhering to the surface of the ceramic injection molded body is removed by surface cleaning treatment, so that no foreign matter remains on the ceramic sintered body after firing. The surface is not roughened, and the surface condition of the obtained ceramic sintered body is extremely good.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

This example shows an example in which a turbo rotor is manufactured as a ceramic sintered body.

Here, FIG. 1 is a process diagram showing each step of a method for manufacturing a ceramic sintered body according to an embodiment of the present invention.

The main component is silicon nitride powder with an average particle size of approximately 1 μm, and 4% by weight of yttrium oxide is added to this silicon nitride powder as a sintering aid.
A kneaded product is prepared by adding 4% by weight of spinel and 17% by weight of paraffin, flaky polypropylene, and ethyl vinyl alcohol as organic binders.

By injection molding this kneaded material into a predetermined mold, an injection molded article in the shape of a turbo rotor was obtained.

This injection molded article was immersed in a 10% hydrochloric acid aqueous solution for 3 minutes, taken out, and subjected to surface cleaning treatment by washing with water to remove the hydrochloric acid.

Subsequently, this injection molded article was placed in a degreasing device and subjected to a degreasing treatment. That is, after introducing an inert gas into the degreasing device and replacing the inside of the device with the inert gas, the inside of the device was heated to 450° C. at a rate of 5° C./hr to perform degreasing.

This turbo rotor-shaped degreased body was placed in a firing furnace, and 175
A ceramic turbo rotor was obtained by firing at 0° C. for 4 hours. The above steps are illustrated in FIG. 1.

(Comparative Example) Here, FIG. 2 is a process diagram showing each step of a conventional method for manufacturing a ceramic sintered body.

In the example, a ceramic turbo rotor was manufactured in substantially the same manner as in the example except that the surface cleaning treatment for cleaning the surface of the injection molded body was not performed.

The steps of this conventional method are illustrated in FIG. 2.

When we investigated the surface conditions of the turbo rotors obtained in the examples and comparative examples, we found that the turbo rotors of the examples showed no residual foreign matter on the surface, and no surface roughness or bores were observed. The turbo rotor obtained had foreign substances such as iron and molybdenum on the surface, and bores and surface roughness were observed.

From the above, it can be seen that according to the method for manufacturing a ceramic sintered body of this example, a ceramic sintered body with a good surface condition can be obtained.

Although specific embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, but includes various embodiments within the scope of the claims.

For example, in the embodiment, an example is shown in which hydrochloric acid is used for surface cleaning treatment, but other acids such as sulfuric acid and nitric acid may also be used.

Moreover, the optimum conditions for the treatment temperature and treatment time can be determined as appropriate, taking into account the type and concentration of the acid used.

〔Effect of the invention〕

As described above, according to the method for manufacturing a ceramic sintered body of the present invention, the surface condition of the ceramic sintered body is always good, and the quality can be improved.

[Brief explanation of the drawing]

FIG. 1 is a process diagram showing each step of a method for manufacturing a ceramic sintered body according to an embodiment of the present invention, and FIG. 2 is a process diagram showing each step of a conventional method for manufacturing a ceramic sintered body. Applicant: Toyota Motor Corporation Figure 1 Figure 2

Claims (1)

[Claims] (1) A method for producing a ceramic sintered body, in which a mixed powder of ceramic powder and a sintering aid is injection molded into a predetermined shape using an organic binder, the resulting injection molded body is degreased, and then fired. A method for producing a ceramic sintered body, characterized in that, after the injection molding, a surface cleaning treatment is performed to clean the surface of the injection molded body.