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:
Feb. 25, 2003
Filed:
Oct. 15, 1996
Masahide Mohri, Ibaraki, JP;
Norio Matsuda, Ibaraki, JP;
Shinichiro Tanaka, Ibaraki, JP;
Yoshio Uchida, Ibaraki, JP;
Yoshinari Sawabe, Ibaraki, JP;
Hisashi Watanabe, Ibaraki, JP;
Hiroshi Ogawa, Ibaraki, JP;
Sumitomo Chemical Co., Ltd., Osaka, JP;
Abstract
Alpha alumina powder having a regulated particle size, a uniform particle shape and a narrow particle size distribution and further a low halogen content is produced by calcining at least one starting material selected from transition alumina and alumina compounds in a halogen-containing atmosphere which comprises a hydrogen halide gas, a halogen gas or a mixture of a halogen gas and steam and contains at least 0.1% by volume of at least one halogen-containing gas selected from the group consisting of hydrogen halide gas and halogen gas, and removing halogen from a calcined material. The produced alpha-alumina powder is excellent in a packing property and homogeneously packed.