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:
Jul. 09, 1991
Filed:
Jul. 19, 1990
Applicant:
Inventors:
Tariq Quadir, Columbia, MD (US);
Roy W Rice, Alexandria, VA (US);
Assignee:
W. R. Grace & Co.-Conn., New York, NY (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C04B / ;
U.S. Cl.
CPC ...
501 98 ; 501 97 ;
Abstract
A sintered silicon nitride product is made having a high flexural strength by sintering a mixture of silicon nitride and a sintering aid containing alumina and at least a three component rare earth oxide mixture which does not contain yttria. Based on the weight of the final sintered nitride product, the three component rare earth oxide mixture comprises about 3 to 6% La.sub.2 O.sub.3, 2 to 5% Nd.sub.2 O.sub.3, and 1 to 4 CeO.sub.2. An additional fourth component, Pr.sub.6 O.sub.11, can be added in an amount of 0.5 to 1.1%.