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. 17, 2007
Filed:
Feb. 28, 2003
Applicant:
Hirohiko Ohtsubo, Shiojiri, JP;
Inventor:
Hirohiko Ohtsubo, Shiojiri, JP;
Assignee:
Showa Denko K.K., Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C01B 21/064 (2006.01); B03D 1/06 (2006.01);
U.S. Cl.
CPC ...
Abstract
A method is provided for producing cubic boron nitride, in which a mixture containing hexagonal boron nitride and a catalyst is maintained under pressure and temperature conditions that thermodynamically favor the stable presence of cubic boron nitride, thereby forming composite lumps containing cubic boron nitride, which in turn are dissolved in an alkaline solution to recover cubic boron nitride. The method is characterized by including, prior to the dissolving step, a step of decreasing the ratio of low-pressure phase boron nitride to cubic boron nitride in the composite lumps down to 50% by mass or less.