| 摘要 |
PROBLEM TO BE SOLVED: To provide a spark plug capable of acquiring a sufficient high temperature oxidation-proof property and spark-proof consumption by using an electrode material wherein an intermetallic compound is deposited on a host phase of nickel as an electrode. SOLUTION: The electrode material wherein nickel is a principal component and the intermetallic compound (N-Y) is deposited at least on a grain boundary is used as a center electrode and a ground electrode of the spark plug. In the center electrode and ground electrode used in a severe environment where spark discharges are repeated while exposed at temperature of approximately 1,000°C, when crystal grains of the electrode material are grown, oxidation of the electrode material is apt to advance since a structure of the grain boundary becomes simple and oxygen is easily penetrated into the inside through the grain boundary. However, the high temperature oxidation-proof property of the electrode material is high because growth of the crystal grain is restrained by the intermetallic compound deposited in the grain boundary, and internal corrosion of the electrode material is hardly generated because oxygen is not included in the compound. Further, the spark-proof consumption of the electrode material is improved by adjusting the contents of components and maintaining heat-conductivity. COPYRIGHT: (C)2009,JPO&INPIT
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