| 摘要 |
PROBLEM TO BE SOLVED: To provide a spark plug capable of restraining abnormal consumption particularly remarkably seen in a radially thinned discharge part in the spark plug for forming the discharge part of a noble metal chip. SOLUTION: The discharge part 31 is formed of the noble metal chip 31'. When an outer diameter of the noble metal chip is set to a chip diameter D (mm), and the shortest distance up to the corresponding edge of a welded part W for welding a central electrode 3 and the noble metal chip 31' is set to the discharge part thickness H (mm), D: 0.3 to 0.8 mm, and H: 0.4 to 2.0 mm are realized. Ir as a main component and Ni of 0.5 of 8 mass% are contained in the noble metal chip 31'.
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