摘要:
In a spark plug for an internal combustion engine, a spark gap is defined between an insulated sparking portion and a grounded sparking portion. At least one of the insulated sparking portion and the grounded sparking portion is made of a molten alloy composed of (a) 99 to 80 wt. % of Ir and (b) 1 to 20 wt. % of Pt. The insulated sparking portion can be a center electrode or a discharge chip attached to a free end of the center electrode, while the grounded sparking portion can be a ground electrode or a discharge chip attached to a free end of the ground electrode.
摘要:
A spark plug for internal combustion engines provided with a noble metal tip on the pointed top of a spark plug center electrode. The noble metal tip is welded to the center electrode top end by heating and pressing the portion to be welded. After the welding, the center electrode is shaped to provide the pointed top. The noble metal tip is a platinum alloy consisting of platinum of 85 through 70 in weight percentage and iridium of 15 through 30 in weight percentage.