IGNITION DEVICE HAVING AN ELECTRODE FORMED FROM AN IRIDIUM-BASED ALLOY

摘要

An ignition device such as a spark plug having ground and center electrodes, at least one of which includes a firing tip formed from an alloy containing iridium, rhodium, tungsten, and zirconium. With the inclusion of tungsten and zirconium in the alloy, the percentage of rhodium can be kept relatively low without sacrificing the erosion resistance or reduced sparking voltage of the firing tip. In one embodiment, the firing tip contains 2.5% rhodium, 0.3% tungsten, 0.07% zirconium, and the balance iridium.