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. 30, 1989
Filed:
Dec. 29, 1987
Hiroyuki Iwasaki, Nagoya, JP;
Masaaki Masuda, Nagoya, JP;
NGK Insulators, Ltd., Nagoya, JP;
Abstract
A process for producing silicon nitride ceramic articles is disclosed, which includes the steps of preparing a mixed powder of silicon nitride and a sintering aid, shaping the mixed powder, sintering the shaped body, machining the sintered body in a desired shape, and then heating the machined sintered body in a temperature range from 550.degree. C. to 900.degree. C. in an oxidizing atmosphere. Alternatively, after the sintering, the sintered body is heated in a temperature range from 950.degree. C. to 1,400.degree. C. to crystallize an Si.sub.3 N.sub.4 grain boundary phase, the crystallized sintered body is machined into a desired shape, and the machined body is heated in a temperature range from 550.degree. C. to 900.degree. C. in an oxidizing atmosphere. Thereby, silicon nitride ceramic articles having high strength at room temperature can be obtained.