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. 23, 2025
Filed:
Mar. 24, 2021
Denka Company Limited, Tokyo, JP;
Takafumi Komaki, Tokyo, JP;
Junya Nitta, Tokyo, JP;
Yoshiaki Okamoto, Tokyo, JP;
Masakazu Hirata, Tokyo, JP;
Genta Karino, Tokyo, JP;
DENKA COMPANY LIMITED, Tokyo, JP;
Abstract
The alumina powder contains: a first alumina particle having an average particle diameter of 0.1 μm or more and less than 1 μm; a second alumina particle having an average particle diameter of 1 μm or more and less than 10 μm; and a third alumina particle having an average particle diameter of 10 μm or more and 100 μm or less, wherein each of the average particle diameters is a particle diameter measured using laser light diffraction scattering particle size distribution analyzer, average sphericity of first alumina particle having projected area equivalent circle diameter of 0.1 μm or more and 1 μm or less as determined by microscopy is 0.80 or more and 0.98 or less, a specific surface area of first alumina particle is 1.9 m/g or more and 20.0 m/g or less, and content ratio of an α crystal phase is 80% by mass or more.