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:
Sep. 08, 1992
Filed:
Dec. 04, 1991
Hiroaki Sakai, Nagoya, JP;
Manabu Isomura, Nagoya, JP;
NGK Insulators, Ltd., , JP;
Abstract
A silicon nitride sintered body having a high strength at high temperatures as well as at room temperature can be provided by the method of the present invention, which includes preparing a raw material consisting of SI.sub.3 N.sub.4 powder, a rare earth element oxide powder, and SiC powder, and at least one of a W compound powder and a Mo compound powder, forming the raw material into a shaped body, and then firing the shaped body in N.sub.2 atmosphere to substantially crystallize the grain boundary phase of the Si.sub.3 N.sub.4 grains. The silicon nitride sintered body includes Si.sub.3 N.sub.4 as a main component, and the remainder of a rare earth element compound, SiC and at least one of a W compound and a Mo compound, the grain boundary phase of Sio.sub.3 N.sub.4 grains consisting substantially of crystal phases. The silicon nitride sintered body is dense and thin in color so that uneven coloring thereof can be decreased.