| 摘要 |
A spark plug including a center electrode; an insulator; a metallic shell; and a ground electrode, wherein at least one of the center electrode and the ground electrode has thereon an intermediate member which connects the center electrode or the ground electrode to a noble metal tip. The intermediate member has a tip-bonding portion to which the noble metal tip is bonded, and an electrode-bonding portion which has a diameter greater than that of the tip-bonding portion, and which is bonded to the center electrode or the ground electrode. The intermediate member contains nickel (Ni) as a main component, and also contains chromium (Cr) in an amount of 15 to 25 wt. %. The intermediate member contains, in a surface portion thereof, silicon (Si) in an amount per unit volume of 0.04 mg/mm3 to 0.12 mg/mm3, and aluminum (Al) in an amount per unit volume of 0.03 mg/mm3 to 0.10 mg/mm3.
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