Why was Iridium not used until today?
A. The extreme strength of the metal inhibited its large-scale usage in spark plugs. However, through recent technological advances, DENSO has harnessed the power of Iridium. DENSOs patented alloy is composed of iridium, complemented by rhodium (an even stronger metal). The rhodium is added to increase oxidation and wear resistance. DENSO was able to make this durable alloy workable by pioneering and patenting a Laser-Welding/process. This process provides a 360-degree weld so reliable that the electrode resists wear, even in the harshest conditions.
