Patents by Inventor Naoto Niwa

Naoto Niwa has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Method for producing two-component or three-component lead zirconate-titanate
    Patent number: 4990324
    Abstract: 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.
    Type: Grant
    Filed: October 4, 1989
    Date of Patent: February 5, 1991
    Assignees: Nippondenso Co., Ltd., Science and Technology Agency Natl. Institute for Research in Inorganic Materials
    Inventors: Masahiro Tomita, Akira Fujii, Naoto Niwa, Hitoshi Niwa, Shin-ichi Shirasaki