| 摘要 |
<p>In a creeping discharge type spark plug (1, 100, 150, 200, 300, 350, 400), the firing surface forming portions (2b, 4a) of a center electrode (2) and a ground electrode (4) are made of a metallic material containing a corrosion impeding component consisting of one or more of Fe, Cr and Cu. The spark plug is attached to an internal combustion engine. When it is operated under conditions of a predetermined high speed and high load, a corrosion impeding layer (30) containing a corrosion impeding component is formed on the surface of the top end of an insulating member (3), with progression of spark discharge in spark discharge gaps (g1, g2). The corrosion impeding layer (30) thus formed protects the center electrode (2) from the attack by the creeping discharge spark. Therefore, the channeling is considerably effectively prevented or restricted. <IMAGE></p> |
