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. 29, 2003
Filed:
Dec. 07, 2001
Applicant:
Inventors:
Shindo Watanabe, Aichi, JP;
Masahiro Konishi, Aichi, JP;
Assignee:
NGK Spark Plug Co., Ltd., Nagoya Aichi, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C04B 3/332 ;
U.S. Cl.
CPC ...
C04B 3/332 ;
Abstract
In the production of a silicon nitride sintered body through a hot press method, a sintering aid protecting agent is added to the raw material. The employable protecting agents are metallic elements such as Ta, W and Mo and compounds of the metallic elements such as nitrides and silicides. Conversion of these elements and compounds to carbides occurs preferentially to reduction of the sintering aid. Thus, it becomes possible to suppress reduction of the sintering aid in a reducing atmosphere formed, for example, of carbon monoxide, which is generated particularly when a graphite pressing die is employed.