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. 07, 2014
Filed:
Apr. 12, 2011
Applicants:
Hiroaki Nasu, Gifu, JP;
Kazuhiro Kodama, Hekinan, JP;
Inventors:
Hiroaki Nasu, Gifu, JP;
Kazuhiro Kodama, Hekinan, JP;
Assignee:
NGK Spark Plug Co., Ltd., Aichi, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H01T 13/20 (2006.01); H01T 13/32 (2006.01); H01T 13/02 (2006.01); F02P 13/00 (2006.01);
U.S. Cl.
CPC ...
H01T 13/02 (2013.01); H01T 13/32 (2013.01); F02P 13/00 (2013.01);
Abstract
A spark plug superior in salt corrosion resistance and stress corrosion cracking resistance is provided. The spark plug includes a metallic shell coated with a composite layer which includes a nickel plating layer and a chromate layer formed on the nickel plating layer. The spark plug is characterized in that the nickel plating layer has a thickness A which satisfies a relational expression 3 μm≦A≦15 μm and that the chromate layer has a thickness B which satisfies a relational expression 2 nm≦B≦45 nm.