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:
Nov. 07, 1995
Filed:
Aug. 11, 1993
Akio Katoh, Nishio, JP;
Nobuo Abe, Yokkaichi, JP;
Takeshi Hanai, Kuwana, JP;
Kenji Horibe, Aichi, JP;
Nippondenso Co., Ltd., Kariya, JP;
Abstract
A composite chip formed by joining a discharging layer and a heat stress relieving layer at a joint interface therebetween beforehand is provided on at least one of a central electrode and a ground electrode in its discharge portion made of an electrode material. The discharging layer is made of a precious metal or a precious metal alloy having superior spark- and wear-resistance, and the heat stress relieving layer is made of a metal or an alloy having a linear expansion coefficient between those of the discharging layer and the electrode material. Formed at the joint interface between both the discharging layer and the heat stress relieving layer through mutual diffusion of those materials developed when the two layers are joined to each other is a diffusion layer, in which concentrations of materials of both the layers are continuously changed. A thickness of the diffusion layer is not less than 3 .mu.m in a state that the composite chip is welded to the discharge portion.