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:
Aug. 01, 1989
Filed:
Apr. 30, 1987
Kawasaki Steel Corp., , JP;
Abstract
A hexagonally crystalline boron nitride containing water-soluble boron containing impurities in such a magnitude that the amount of boron contained in an extract after boiling at 100.degree. C. in pure water is less than or equal to 100 .mu.g per gram of boron nitride. In order to purify the boron nitride, a purification process is carried out according to the steps of preparing fine particles of boron nitride powder; dispersing the boron nitride powder in a dispersion medium and stirred for a given period of time for removing water-soluble boron containing impurities; and drying the boron nitride in atmosphere, in which the vapor pressure is maintained lower than or equal to 10 mmHG and/or the process temperature is maintained lower than or equal to 100.degree. C.