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:
Mar. 10, 2020
Filed:
Jun. 22, 2018
Ngk Spark Plug Co., Ltd., Nagoya-shi, Aichi, JP;
Haruki Yoshida, Tajimi, JP;
Kuniharu Tanaka, Komaki, JP;
Shun Kondo, Obu, JP;
Yutaka Yokoyama, Kasugai, JP;
Yusuke Nomura, Niwa-gun, JP;
Michitaka Yamada, Tajimi, JP;
NGK SPARK PLUG CO., LTD., Nagoya, JP;
Abstract
The spark plug includes an insulator made from an alumina-based sintered body, and the insulator contains 90 to 98 wt % of an Al component in oxide equivalent. The insulator contains 1 to 5 wt % of an Si component, 0.1 to 1 wt % of an Mg component, 2 wt % or less of a Ca component, 0.3 to 6 wt % of a Ba component, and 0.11 to 5 wt % of a rare earth component, in oxide equivalent. In analysis using a scanning transmission electron microscope with a probe diameter of an electron beam set at 1 nm, Si and a rare earth element are detected at a crystal grain boundary having a thickness of 15 nm or less, and an alkaline earth metal at the crystal grain boundary is less than a detection limit.