JPS60141671A - Manufacture of zirconia 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 The present invention provides a zirconia sintered body (
The present invention relates to a method for producing a sintered body (hereinafter referred to as a sintered body).

Conventionally, it has been reported in 1983 that bending strength, hardness, etc. are significantly improved when sintered bodies are manufactured by adding small amounts of oxides such as yttrium and magnesium as zirconium oxide stabilizers.
This is known from Japanese Patent No. 9784. How to manufacture such a sintered body.

The crystal grains contained in the sintered body are created by using ultrafine raw material powder, which is a uniform mixture of zirconium oxide and a stabilizer using gas phase and liquid phase reactions, and firing it under strictly controlled temperature conditions. It is necessary to specify the diameter. However, it is expensive because it uses fine particles produced through a complicated process as a raw material, and it is difficult to manufacture large products because it is prone to large shrinkage during the molding or firing process, causing cracks and deformation. Furthermore, the crystal form of the sintered body using yttrium oxide changes at 200 to 300°C, and the crystal form of the sintered body using magnesium oxide changes at 1000°C.
It cannot be used for long periods in areas that are exposed to heat because its strength will decrease. For this reason, the characteristic of the sintered body, which is good heat insulation, was not utilized.

It is an object of the present invention to provide a method for producing a sintered body free of such drawbacks.

The inventors of the present invention have carried out various studies regarding the above-mentioned drawbacks, and have found that adding zirconium oxide powder and cerium oxide powder as a stabilizer to zirconium oxide powder is better than adding either one of them alone. The strength has been increased, the thermal stability of the sintered body has been improved, and the raw material powder used no longer needs to be ultra-fine, reducing raw material costs and making it easier to manufacture large products without cracking or deformation. I found it.

The present invention uses zirconium oxide powder of 65.0 to 96.0% by weight.
, a sintered body formed by molding and firing a mixture consisting of cerium oxide powder 0.6 to 26.0% by weight and yttrium oxide powder 0.8 to 9.0% by weight, and zirconium oxide powder 65.0%
~96.0% by weight, cerium oxide powder 0.6-26.0% by weight and yttrium oxide powder 0.8-9.0% by weight. It relates to a method for producing a sintered body by adding less than % by weight, shaping and firing.

In the present invention, the content of cerium oxide powder is 0.6 to 26
．． If the amount is less than 0.6% by weight, there will be no effect of improving the thermal stability of the sintered body.

If it exceeds 26.0% by weight, the sintered body will have good thermal stability but will have low strength. The content of IJum powder is 0.
．． The content is in the range of 8 to 9.0% by weight, and if it is less than 0.8% by weight, no effect of increasing the strength will be obtained by addition, and if it exceeds 9.0% by weight, the strength of the sintered body will decrease. In addition, the content of zirconium oxide powder is in the range of 65.0 to 96.0% by weight; if it exceeds 96.0% by weight, the strength and thermal stability of the sintered body will be poor, and if it is less than 65.0% by weight, the sintered body will have poor strength and thermal stability. If it exists, the strength of the sintered body will decrease.

In the second invention, aluminum oxide powder is added, but the amount added is 50% or more by weight or more than 100% by weight of the mixture of the above raw materials.
If the amount is less than 50% by weight, the strength of the sintered body will decrease.

In addition, each raw material powder used has a purity of 99% or more and an average particle size of 5.
A zirconium oxide powder with a diameter of μm or less is desirable, and relatively low-grade powders used for piezoelectric material production, paints, etc., and also as raw materials for refractories can be used.

Note that the zirconium oxide powder content may include oxidized ..fnium powder, which has similar properties to zirconium oxide and is difficult to separate. The zirconium oxide powder also includes materials that become zirconium oxide when heated, such as zirconium carbonate powder and zirconium hydroxide powder.

As for yttrium oxide powder, cerium oxide powder and aluminum oxide powder, lower grade powders, hydroxides, etc. may be used in the same manner as above.

The raw materials are mixed using a wet ball mill mixing method.

It is desirable to mix the raw materials and grind them to an average particle size of 1 μIn or less, as this results in a sintered body with better properties.

In addition, in the present invention, two or three types of zirconium oxide powder, yttrium oxide powder, and cerium oxide powder (the remaining one is added after heat treatment) are mixed and pulverized at 1000°C or higher, preferably at 1300 to 1450°C. Then, in the second invention, aluminum oxide powder is added and mixed.

Pulverization is preferable for manufacturing large products because it can reduce dimensional variations or cracks during molding and firing.

The firing temperature is preferably 1500 to 1700°C.

A temperature of 1,550 to 1,650°C is preferable because variations in performance are small and a high-performance sintered body can be obtained.

The present invention will be explained below with reference to Examples.

Example 1 Zirconium oxide powder (manufactured by Rare Elements, EP grade, purity 99.5%), yttrium oxide powder (manufactured by Shin-Etsu Chemical, purity 99.9%), and cerium oxide powder (manufactured by Shin-Etsu Chemical, purity 99.9%) ) were weighed to the proportions shown in Table 1, wet milled in a ball mill until the average particle size was 1.0 μm or less,
Mixed. Next, after drying, heat treatment was performed at 1400°C for 1 hour to obtain an intermediate raw material. Aluminum oxide powder (manufactured by Alcoa, trade name A-168G) was added in the amount shown in Table 1 to this intermediate raw material, and the average particle size was 0.7 μm using a ball mill again.
Wet milled and mixed until . This mixture (powder 50
Add polyvinyl alcohol (100% water, 49.9% water) to
I) VA) 0.08% by weight and Wax 002% by weight were added and granulated by spray drying to obtain molded powder, and the molded powder was further pressure molded at a pressure of 1.2 tons/cm2. A molded body of 6 x 12 x 100 mm was obtained. Next, this molded body was fired at a temperature of 1400 to 1700°C to obtain a sintered body.

Next, various tests were conducted using the sintered bodies obtained by firing at the temperatures at which high strength was obtained by firing at the above-mentioned temperatures, that is, at the temperatures shown in Table 1.

The test results are shown in Table 1. In addition, in the test method, 2 bending strength is a 3-point bending test method, and thermal stability is 6
One end of the molded product measuring 12×100 m was heated to 1200° C., and the other end was left at room temperature for 1000 hours, and then the bending strength was examined.

Table 1 shows that the sintered bodies obtained by the manufacturing method of the present invention have high thermal stability and high mechanical strength.

Example 2 Zirconium oxide powder (manufactured by Daiki Elements, ACGM grade, purity 99.2%, also containing 0.3% by weight of silicon oxide, 0.2% by weight of ferric oxide, and 0.3% by weight of titanium oxide) , yttrium oxide powder (manufactured by Shin-Etsu Chemical).

purity 99.9%) and cerium oxide powder (manufactured by Shin-Etsu Chemical,
(purity 99.9%) was weighed to the blending ratio shown in Table 2, and a sintered body was obtained in the same manner as in Example 1. Various tests were also conducted in the same manner as in Example 1, and the test results are also shown in Table 2. Note that various tests were conducted using sintered bodies obtained by firing at 1600°C.

According to Table 2, the sintered body obtained by the manufacturing method of the present invention has high thermal stability as in Example 1.

This indicates high mechanical strength.

According to the present invention, ultrafine raw material powder is used.

Since precise temperature control is not required, a sintered body with high strength and high heat resistance can be easily produced at low cost.

In addition, depending on the amount of cerium oxide powder added, it can be used for heat-insulating mechanical parts suitable for use at room temperature to high temperatures, and large-sized products can also be manufactured.

Agent: Patent Attorney Kunihiko Wakabayashi

Claims (1)

[Claims] 1. Zirconium oxide powder 65.0 to 96.0% by weight. A method for producing a zirconia sintered body, which comprises molding and firing a mixture consisting of 0.6 to 26.0% by weight of cerium oxide powder and 0.8 to 9.0% by weight of yttrium oxide powder. 2. Zirconium oxide powder 65.0-96.0% by weight. Mixture 5 consisting of 0.6 to 26.0% by weight of cerium oxide powder and 0.8 to 9.0% by weight of yttrium oxide powder
A method for producing a zirconia sintered body, which comprises adding aluminum oxide powder in an amount of 0% by weight or more and less than 100% by weight and 50% by weight or less, followed by molding and firing.