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:
Dec. 30, 2014
Filed:
Nov. 26, 2010
Osamu Yoshimoto, Inazawa, JP;
Tomo-o Tanaka, Aichi, JP;
Norihide Kachikawa, Seto, JP;
NGK Spark Plug Co., Ltd., Aichi, JP;
Abstract
A spark plug () includes a metallic shell () and a ground electrode () resistance-welded to the metallic shell (). The ground electrode () is formed from a metal material in which precipitates PR containing at least one of an oxide, an intermetallic compound, etc., are precipitated in grain boundaries. The diameter of an equivalent circle of a precipitate PR having the greatest area is 50 μm or less, and the shortest distance between the precipitates PR is 2 μm or greater. The area occupied by the precipitates PR on the section of the heat-affected zoneA is equal to 65% or more the area occupied by the precipitates PR (the diameter of an equivalent circle of a precipitate PR having the greatest area) on a section of the normal zoneB.