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:
Apr. 24, 2012
Filed:
Sep. 18, 2007
Norifumi Azuma, Ehime, JP;
Shinji Fujiwara, Ehime, JP;
Norifumi Azuma, Ehime, JP;
Shinji Fujiwara, Ehime, JP;
Sumitomo Chemical Company, Limited, Tokyo, JP;
Abstract
α-Alumina powder having a purity of at least 99.99% by weight, a specific surface area of from 0.1 to 2.0 m/g, a relative density of from 55 to 90%, and a closed porosity of 4% or less, wherein in a weight-based particle size distribution obtained by the dry sieving test according to JIS K0069 (1992), an amount of particles having a particle size of less than 75 μm is 5% by weight or less; an amount of particles having a particle size exceeding 2.8 mm is 15% by weight or less; and at least one frequency maximum peak appears in a particle size range of 100 μm or more and to less than 850 μm. This α-alumina powder can be charged in a crucible at a high bulk density, from which sapphire having a few voids can be produced without causing the oxidation of a crucible in a heat melting step.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile