Nippondenso Co., Ltd.

National Institute for Research in Inorganic Materials

Science and Technology Agency National Institute for Research in

Science and Technology Agency Natl. Institute for Research in Inorganic

Shin-ichi Shirasaki

Masahiro Tomita

Hitoshi Niwa

Akira Fujii

Naoto Niwa

A process for producing a high density ceramic of perovskite represented by the formula:

Process for producing a high density ceramic of perovskite

Aqueous titanium tetrachloride solution and aqueous zirconium nitrate solution of components except zirconium, for forming lead zirconate-tinatate in which part of the lead is substituted for any of the lanthanide elements are mixed, and the mixture is hydrolyzed to form sol. This sol is cleaned, dried, and calcined at 1100.degree. C. to form modified powder. The compounds of the remaining component of lead zirconate-titanate, such as TiO.sub.2 powder, PbO powder and Sm.sub.2 O.sub.3 powder, are mixed with the modified powder, and the resultant mixture is calcined at 750.degree. C. for 1 hour to produce the lead zirconate-titanate.

Method for producing two-component or three-component lead

Aqueous titanium tetrachloride solution, i.e., one component (X) for forming multi-component ceramic compound, and a suitable amount of zirconium oxynitrate, i.e., another component (Y) are mixed. Hydroxide coprecipitate of Ti.sup.4+ and Zr.sup.4+ containing the components is formed from the mixture solution. The coprecipitate is cleaned, dried, then calcined, for example, at 1100.degree. C., thus producing powder containing 0.32-micron particles. This powder is mixed with TiO.sub.2 and PbO, in a suitable amount to be added to the other component (Y) of the multi-component ceramic compound. The resultant mixture is calcined, for example, at 740.degree. for 1 hour, into fine powder containing 0.32-micron particles. The calcined powder is then press-molded, for example, under the pressure of 1 ton/cm.sup.2, then calcined, for example, at 1220.degree. C. for 1 hour, thereby forming multi-component ceramics.

Method for producing multi-component ceramics

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Tsukuba, Japan

Shin-ichi Shirasaki