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:
Nov. 10, 1998
Filed:
Jun. 19, 1997
Keiichiro Watanabe, Kasugai, JP;
Youky Bessyo, Nishikasugai-gun, JP;
NGK Insulators, Ltd., Nagoya, JP;
Abstract
In a process for producing a silicon nitride sintered material, a silicon nitride raw material powder selected from raw material powder lots such that the silicon nitride raw material powder has a dispersion .delta.N.beta..sub.1 of weight fraction of .beta.-silicon nitride, of 65% or less, is used. A process for producing a silicon nitride sintered material controls the firing conditions so that the raw material being fired gives, at any stage of firing, a dispersion .delta.N.beta..sub.2 of weight fraction of .beta.-silicon nitride, of 65% or less between the surface portion and the central portion. The first process allows for production of a silicon nitride sintered material having excellent properties in high-temperature strength, etc., at a high reproducibility and stability. The second process allows for production, of in any production batch, a silicon nitride sintered material very low in scattering of properties (e.g., density and strength) between the central portion and the surface portion.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile