Patents by Inventor Yen-Hwei Chang

Yen-Hwei Chang 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).

  • Methods for preparing lead lanthanum zirconatetitanate powders with carbonate processes
    Patent number: 4965056
    Abstract: A method of preparing PLZT powder with a carbonate process employing Pb(NO.sub.3).sub.2, zirconium oxychloride and chlorides of La and Ti as starting materials. Solutions of each are blended together and added to a solution consisting of NH.sub.4 OH and (NH.sub.4).sub.2 CO.sub.3. The resulting solution undergoes refluxing at proper conditions for a period of time to coprecipitate a majority of particles which form nuclei covered by the carbonates of La, Ti and Pb, and a minority of particles which form nuclei which are covered by the hydroxides of La, Ti and Pb, which are calcined and ground to form PLZT powder.
    Type: Grant
    Filed: April 11, 1990
    Date of Patent: October 23, 1990
    Assignee: Ming-Chin Wu
    Inventor: Yen-Hwei Chang