Title:
内燃機関用スパークプラグ
Document Type and Number:
Japanese Patent JP4847992
Kind Code:
B2
Abstract:
The invention relates to a spark plug in which a noble-metal chip formed from a Pt alloy is joined to an end portion of an electrode formed from an Ni alloy, and an object is to restrain coming-off of the noble-metal chip, to thereby enhance durability. A ground electrode 27 and a noble-metal chip 32 are joined together via a weld portion 42 formed by means of an Ni alloy and a Pt alloy being fused and mixed. A plurality of acicular and/or rhizoid microcracks 51 are formed in the weld portion 42. As viewed on a section of the weld portion 42, the average length of the microcracks is 50 µm to 500 µm, and the average aspect ratio (shorter dimension/longer dimension) of the microcracks is 0.05 or less. At least one of the Ni alloy used to form the ground electrode 27 and the Pt alloy used to form the noble-metal chip 32 contains as an additive at least one of the elements belonging to Groups 3A and 4A of the Periodic Table and/or oxides of those elements.
Inventors:
Osamu Yoshimoto
Application Number:
JP2008204421A
Publication Date:
December 28, 2011
Filing Date:
August 07, 2008
Export Citation:
Assignee:
Nippon Special Ceramics Co., Ltd.
International Classes:
H01T13/20; C22C5/04; C22C19/05; H01T13/39
Domestic Patent References:
| JP2004165165A | ||||
| JP5159855A | ||||
| JP2001257053A | ||||
| JP2006185853A | ||||
| JP2007172866A |
Attorney, Agent or Firm:
Mitsuo Kawaguchi