| 摘要 |
PROBLEM TO BE SOLVED: To provide a long-life sparkplug for internal combustion engines having excellent spark-resisting property and oxidation resistance. SOLUTION: A sparkplug 1 for internal combustion engines has a center electrode 2 and a ground electrode 3 for forming a spark discharge gap 11 between them, and the center electrode 2 and the ground electrode 3 are formed by attaching noble-metal center electrode chip 21 and a ground electrode chip 31 to the opposed positions to each other, respectively. At least one side of the center electrode chip 21 or the ground electrode chip 31 is composed mainly of Rh, and contains 0.3-2.5% by weight of at least one element selected from the group consisting of rare earth elements, group IVA elements, and group VA elements. COPYRIGHT: (C)2007,JPO&INPIT
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