The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 23, 1989
Filed:
Feb. 01, 1988
Jameel Menashi, Lexington, MA (US);
Robert C Reid, Lexington, MA (US);
Laurence P Wagner, North Reading, MA (US);
Cabot Corporation, Waltham, MA (US);
Abstract
The present invention involves a method for producing a variety of barium titanate based powder products consisting of submicron, dispersible primary particles having narrow size distributions. The method, in its broadest aspects, involves heating an aqueous slurry of PbO, or Pb(OH).sub.2, and Ca(OH).sub.2 with a stoichiometric excess of the hydrous oxides of Ti(IV), Sn(IV), Zr(IV) and Hf(IV) to a temperature not exceeding 200.degree. C. Thereafter, the resulting slurry temperature is adjusted to between 50.degree. and 200.degree. C. and a solution of Ba(OH).sub.2 and Sr(OH).sub.2, having a temperature of 70.degree. to 100.degree. C. is added within a period of five minutes or less to the slurry. About 10 minutes after the addition of the Ba(OH).sub.2 and Sr(OH).sub.2 solution is completed, the slurry is heated to a temperature not exceeding 225.degree. C. to ensure formation of a stoichiometric perovskite product. Thereafter, the slurry is cooled and the solid product is recovered.