SPARK PLUG TIP HAVING PLATINUM BASED ALLOYS

摘要

A spark plug and method of making same, wherein the spark plug includes a platinum alloy tip portion which takes the form of a rivet or a sphere. The tip portion is annealed in an annealing furnace at a temperature between abo ut 700~-1400 ~C for a time between about 5-30 minutes. The annealed tip portion is then resistance welded to an electrode of the spark plug. The annealing provides the tip portion with added resistance to corrosion and attack by lead. Preferred embodiments of the spark plug tip material comprise 80 % platinum - 20 % rhodium; 80 % platinum - 20 % iridium; 96 % platinum - 4 % tungsten; and Pt (bal) - Ir (a) %-W(b) %, where "a" ranges from about 15 to 19 percent by weight; "b" ranges from about 1 to 4 percent by weight, and the balance is comprised of platinum and incident impurities, and wherein the su m of iridium and tungsten present ranges from about 16 to 19.