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:
Jan. 14, 1992
Filed:
Aug. 17, 1990
Applicant:
Inventors:
Yoshio Ukyo, Aichi, JP;
Shigetaka Wada, Aichi, JP;
Assignee:
Kabushiki Kaisha Toyota Chuo Kenkyusho, Aichi, JP;
Primary Examiner:
Int. Cl.
CPC ...
C04B / ;
U.S. Cl.
CPC ...
501 97 ; 501 98 ; 428698 ; 428702 ; 264 60 ;
Abstract
A sintered body composed of .alpha.'-silicon nitride and .beta.'-silicon nitride, and having a surface portion which contains a greater proportion of .alpha.'-silicon nitride than its inner portion does. It has high strength and excellent wear resistance. It is produced by preparing a molded body from a sintering material, disposing about the molded body a sintering material which can form a sintered product containing a greater proportion of .alpha.'-silicon nitride than the sintered product of the molded body will, and sintering the molded body and the material disposed about it.