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:
Oct. 02, 2012
Filed:
Mar. 09, 2010
Hirokazu Kurono, Nagoya, JP;
Toshitaka Honda, Nagoya, JP;
Katsuya Takaoka, Komaki, JP;
Hiroki Takeuchi, Niwa-gun, JP;
Kuniharu Tanaka, Komaki, JP;
Takeshi Mitsuoka, Kounan, JP;
Hirokazu Kurono, Nagoya, JP;
Toshitaka Honda, Nagoya, JP;
Katsuya Takaoka, Komaki, JP;
Hiroki Takeuchi, Niwa-gun, JP;
Kuniharu Tanaka, Komaki, JP;
Takeshi Mitsuoka, Kounan, JP;
NGK Spark Plug Co., Ltd., Nagoya, JP;
Abstract
A spark plug exhibits a satisfactory withstand voltage characteristic and sufficient mechanical strength in a high temperature environment exceeding 700° C. The spark plug has a center electrode, an insulator, and a ground electrode, characterized in that the insulator is formed of an alumina-based sintered material containing an Si component, a Group 2 element (2A) component, and a rare earth element (RE) component; that the alumina-based sintered material has an RE-β-alumina crystal phase; and that the mean crystal grain size D(RE) of the RE-β-alumina crystal phase and that of alumina D(Al) satisfy the following relationship (1):0.2≦()/(Al)≦3.0.