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:
Jun. 25, 1991
Filed:
Mar. 14, 1990
NGK Insulators, Ltd., Nagoya, JP;
Abstract
A sintered silicon nitride contains at least 90% of .beta.-type silicon nitride, wherein said .beta.-type silicon nitride consists essentially of 35 to 80% of large crystal particles with the remainder of small crystal particles, said large crystal particles having a mean particle length being at least two times as long as that of said small crystal particles. This sintered silicon nitride is obtained by a method wherein one batch of starting silicon nitride powders, whose primary particles have a mean particle size of 0.1 to 0.5 .mu.m, and another batch of starting silicon nitride powders, whose primary particles have a mean particle size of 0.5 to 0.7 .mu.m, are blended with a sintering aid or aids at a given weight ratio, and the thus obtained blend is formed or compacted and sintered.