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:
May. 16, 2017
Filed:
Sep. 22, 2016
Ngk Spark Plug Co., Ltd., Nagoya-shi, Aichi, JP;
Yutaka Yokoyama, Kasugai, JP;
Kuniharu Tanaka, Komaki, JP;
Katsuya Takaoka, Ichinomiya, JP;
Shun Kondo, Obu, JP;
Nobuyoshi Araki, Nagoya, JP;
Toshiki Kon, Komaki, JP;
Haruki Yoshida, Tajimi, JP;
Jumpei Isasa, Aichi, JP;
Hirokazu Kurono, Nagoya, JP;
Hironori Uegaki, Nagoya, JP;
Toshimasa Saji, Konan, JP;
Yusuke Nomura, Aichi, JP;
NGK SPARK PLUG CO., LTD., Aichi, JP;
Abstract
A spark plug including an insulator containing not less than 92 mass % and not greater than 96 mass % of Al component in terms of oxide, wherein the insulator is formed from an alumina sintered body comprising alumina crystal and a grain boundary phase present between crystal grains of the alumina crystal. Assuming that mass contents of an Si component, an Mg component, a Ba component, and a Ca component in terms of oxide are represented by M, M, M, and M, respectively, and a sum of M, M, M, and Mis represented by Mt, the grain boundary phase contains these components so as to satisfy conditions (1) to (4) as follows: (1) 0.17≦M/Mt≦0.47; (2) 0.005≦M/Mt≦0.07; (3) 0.29≦M/Mt≦0.77; (4) 0.03≦M/Mt≦0.19.