SPARK PLUG - NGK SPARK PLUG CO

Title:

SPARK PLUG

Document Type and Number:

WIPO Patent Application WO2010109792

Kind Code:

A1

Abstract:

Disclosed is a spark plug which is provided with an insulating body that exhibits satisfactory withstand voltage characteristics and mechanical strength even in a high temperature environment higher than 700°C. Specifically disclosed is a spark plug (1) which is provided with a center electrode (2), an insulating body (3) and a ground electrode (6). The spark plug (1) is characterized in that the insulating body (3) is configured of an alumina-based sintered body containing an Si content, a group 2 element (2A) content and a rare earth element (RE) content, and the alumina-based sintered body has an RE-ß-alumina crystal phase. The spark plug (1) is also characterized in that the average crystal grain size of the RE-ß-alumina crystal phase (DA(RE)) and the average crystal grain size of the alumina (DA(Al)) satisfy the following condition (1). Condition (1): 0.2 = DA(RE)/DA(Al) = 3.0

Inventors:

KURONO HIROKAZU (JP)
HONDA TOSHITAKA (JP)
TAKAOKA KATSUYA (JP)
TAKEUCHI HIROKI (JP)
TANAKA KUNIHARU (JP)
MITSUOKA TAKESHI (JP)

Application Number:

PCT/JP2010/001655

Publication Date:

September 30, 2010

Filing Date:

March 09, 2010

Export Citation:

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Assignee:

NGK SPARK PLUG CO (JP)
KURONO HIROKAZU (JP)
HONDA TOSHITAKA (JP)
TAKAOKA KATSUYA (JP)
TAKEUCHI HIROKI (JP)
TANAKA KUNIHARU (JP)
MITSUOKA TAKESHI (JP)

International Classes:

H01T13/38; C04B35/111

Domestic Patent References:

WO2005033041A1

2005-04-14

Foreign References:

JP2000272957A	2000-10-03
JP2003112964A	2003-04-18
JP2000313657A	2000-11-14
JP2008127263A	2008-06-05
JP2001002464A	2001-01-09
JP2001335360A	2001-12-04

Other References: