Spark plug

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PROBLEM TO BE SOLVED : To suppress the occurrence of pre-ignition while ensuring oxidation resistance of an electrode. SOLUTION : A spark plug comprises : a center electrode; and a grounding electrode with a gap formed between the center electrode and itself. At least one electrode of the center electrode and the grounding electrode is formed by a nickel alloy including nickel as a primary component and 20 mass% or more of chromium. Of the electrodes, the part formed by the nickel alloy is 0.1 mass% or more in silicon content, and 0.01 mass% or more in the total content of one or more kinds of particular elements selected from an element group consisting of rare earth elements. Of an entire area of a section in parallel with a longitudinal direction, the areal percentage that voids account for is 1% or less. SELECTED DRAWING : Figure 2 COPYRIGHT : (C)2018, JPO&INPIT