| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a spark plug wherein while using a noble metal ignition part having a small diameter, its excessive temperature elevation can be suppressed, thereby a life-elongation of the noble metal ignition part can be aimed at. SOLUTION: As for the spark plug 100, the tip part to position at a spark discharge gap g side of the central electrode 3 is made to be the noble metal ignition part 31 of a diameter of 0.7 mm or less. Then, the central electrode base material 3f with which the noble metal ignition part 31 is jointed is constituted of a Ni alloy of 30 W/m.K or more of thermal conductivity.</p> |
