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:
Dec. 26, 1995
Filed:
Mar. 29, 1994
Jin-Joo Park, Itami, JP;
Atsushi Kimura, Itami, JP;
Koji Yamaguchi, Itami, JP;
Akira Yamakawa, Itami, JP;
Sumitomo Electric Industries, Ltd., Osaka, JP;
Abstract
The invention relates to material silicon nitride powder used for production of silicon nitride ceramics products. Provided herein is a material powder which can offer a compact having a homogeneous packing structure of the powder with good reproducibility and also to provide a method for producing the same. According to the method, a silicon nitride powder is heat treated in two-stage processing, one stage in an inert gas or reducing atmosphere at 100.degree. C.-1000.degree. C. for 5-600 min., and another stage in an oxidizing atmosphere at 300.degree. C.-1200.degree. C. for 5-600 min. As a result of this treatment, a silicon nitride powder is obtained in which its powder particles are crystalline in their interior and are coated with an amorphous layer having a 1-10 nm surface thickness and composed mainly of Si, N, O, and H, an atomic number ratio of oxygen to nitrogen (O/N) of the surface layer being within a range of 0.1-2.0.