| 摘要 |
PROBLEM TO BE SOLVED: To provide a gasket for a spark plug having a chromate film coating a surface with a little hexavalent chromium content, and having excellent anticorrosion property and heat-resisting property compared with a conventional chromate film. SOLUTION: This gasket 30 is used being inserted in a base end part of a mounting screw 7 formed in an outer circumferential surface of a principal metal fitting 1 of the spark plug 100. 95wt% or more of the chromium component contained in at least a part of its surface is tervalent chromium, and a hydroxide of nickel, cobalt or copper is contained in the film. COPYRIGHT: (C)2006,JPO&NCIPI
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