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. 01, 1999
Filed:
Jul. 18, 1996
Applicant:
Inventors:
Kazuhiro Urashima, Aichi, JP;
Shigeru Iwase, Aichi, JP;
Assignee:
NGK Spark Plug Co., Ltd., Aichi, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C04B / ; C04B / ;
U.S. Cl.
CPC ...
501 973 ; 501 982 ; 264683 ;
Abstract
To provide a silicon nitride based sintered material having high strength and high hardness and superior in reliability, silicon nitride sintered material has a composition mainly composed of silicon nitride or Si--Al--O--N, and further comprises 0.5 to 3 wt % of a Mg component, calculated as MgO, and 3 to 10 wt % of a Yb component, calculated as Yb.sub.2 O.sub.3. As a secondary crystal phase, the material contains one or more of Yb.sub.2 Si.sub.3 N.sub.4 O.sub.3, Yb.sub.2 Si.sub.3 N.sub.2 O.sub.5 and Yb.sub.4 Si.sub.2 N.sub.2 O.sub.7. Silicon nitride or Si--Al--O--N comprises 20-50 vol % of needle-like crystals of the entire material.