Patents Assigned to Science and Technology Agency National Institute
  • Patent number: 4970182
    Abstract: 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.
    Type: Grant
    Filed: June 9, 1989
    Date of Patent: November 13, 1990
    Assignees: Nippondenso Co., Ltd., Science and Technology Agency National Institute for Research in Inorganic Materials
    Inventor: Shin-ichi Shirasaki
  • Patent number: 4832893
    Abstract: A method for producing PLZT generally expressed as (Pb.sub.1-x La.sub.x) (Zr.sub.1-y Ti.sub.y).sub.1-x/4 O.sub.3 (0<x.ltoreq.0.3, 0.ltoreq.y.ltoreq.1.0) comprises the steps of forming a coprecipitated body by reacting solution containing at least one of Pb, La and Ti with a zirconium-containing solution and a precipitation-forming solution, or (a) forming a solution containing at least one of Pb, La and Ti forming PLZT generally expressed as (Pb.sub.1-x La.sub.x) (Zr.sub.1-y Ti.sub.y).sub.1-x/4 O.sub.3 (0<x.ltoreq.0.3, 0.ltoreq.y.ltoreq.1.0) and a zirconium-containing solution and carrying out a hydrolysis reaction to produce a sol body, (b) drying and then presintering the coprecipitated body at a temperature of from 700.degree. to 1300.degree. C. to form a modified zirconia powder, (c) mixing the presintered body with a compound having a remaining component composition of a required PLZT composition, (d) presintering the mixture at a temperature of from 500.degree. to 1000.degree. C.
    Type: Grant
    Filed: December 16, 1987
    Date of Patent: May 23, 1989
    Assignees: Nippondenso Co., Ltd., Science and Technology Agency National Institute
    Inventors: Michio Hisanaga, Kazunori Suzuki, Masataka Naito, Shinichi Shirasaki