SPARK PLUG FOR INTERNAL COMBUSTION ENGINE

摘要

PROBLEM TO BE SOLVED: To provide a long-life and inexpensive spark plug for an internal combustion engine, excellent in spark discharging wear resistance and oxidation resistance.SOLUTION: A spark plug 1 includes a center electrode 2 and an earth electrode 3 provided with a spark discharging gap G between the center electrode 2 and the earth electrode 3. An electrode chip 4 is formed on the center electrode 2 and the earth electrode 3. The electrode chip 4 contains 40-60 mol% of aluminum and iridium as a remainder thereof. The electrode chip 4 may contain 1-20 mol% of at least one or more selected from among Ni, Fe, Co, Pt and Rh, in replace of a part of Ir.