| 摘要 |
<p>Disclosed is a spark plug in which a ground electrode can be assuredly prevented from overheating while securing sufficient improvement in oxidation resistance. The spark plug (1) has a metal shell (3) and a ground electrode (27). The ground electrode (27) includes an electrode base portion (271) extending from a front end portion of the metal shell (3) toward the front, a bent portion (272) connected at one end thereof to a front end of the electrode base portion (271) and an electrode distal end portion (273) extending from the other end of the bent portion (272) and forming a spark discharge gap (28) with a center electrode (5). The ground electrode (27) has a base material and a coating layer (31) applied to the base material. The coating layer (31) is formed on at least a front end face (27F) and an outer circumferential surface other than a center-electrode-side surface (27A) of the electrode distal end portion (273) of the ground electrode (27). The base material of the ground electrode (27) is exposed at least at a part of the electrode base portion (271).</p> |
