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:
Sep. 20, 1994
Filed:
Jun. 15, 1993
Haruyoshi Kuwabara, Gunma, JP;
Akio Otsuka, Gunma, JP;
Yasuyuki Maki, Annaka, JP;
Meguru Kashida, Annaka, JP;
Shin-Etsu Chemical Co., Ltd., Tokyo, JP;
Abstract
High-packing silicon nitride powder is prepared by reacting metallic silicon powder having a mean particle size of 1 to 10 .mu.m and a purity of at least 99% directly with nitrogen for forming silicon nitride powder, milling the silicon nitride powder in a dry attritor until the tap density exceeds 0.9 g/cm.sup.3 and the content of particles having an aspect ratio of up to 3 exceeds 95% by weight, and further milling the silicon nitride powder in a wet attritor for finely dividing coarse particles having a particle size of at least 2 .mu.m. The silicon nitride powder has a tap density of at least 0.9 g/cm.sup.3 and a mean particle size of 0.4 to 0.6 .mu.m and contains at least 95% by weight of particles having an aspect ratio of up to 3 and up to 5% by weight of coarse particles having a particle size of at least 2 .mu.m. The powder is moldable into a high density compact, from which a sintered part having improved dimensional precision and strength is obtained.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile