ELECTRODE FOR AN IGNITION DEVICE

摘要

An electrode for an ignition device is made from a dilute nickel alloy which has improved resistance to high temperature oxidation, sulfidation, corrosive wear, deformation and fracture and includes at least 90% by weight of nickel; zirconium; boron and at least one element from the group consisting of aluminum, magnesium, silicon, chromium, titanium and manganese. The weight ratio of Zr/B may range from about.5 to 150, and may include amounts of, by weight of the alloy, 0.05-0.5% zirconium and 0.001- 0.01% boron. The oxidation resistance of the alloy may also be improved by the addition of hafnium to the alloy in an amount that is comparable to the amount of zirconium, which may include an amount of, by weight of the alloy, 0.005-0.2% hafnium. Electrodes of dilute nickel alloys which include aluminum and silicon, as well as those which include chromium, silicon, manganese and titanium, are particularly useful as spark plug electrodes. These electrode alloys of the may also include at least one of cobalt, niobium, vanadium, molybdenum, tungsten, copper, iron, carbon, calcium, phosphorus or sulfur as trace elements, generally with specified maximum amounts. The ignition device may be a spark plug which includes a ceramic insulator, a conductive shell, center electrode and ground electrode. The center electrode, ground electrode, or both, may be made from the dilute nickel alloy of the invention. These electrodes may also include a core with thermal conductivity greater than that of the dilute nickel alloy, such as copper or silver or their alloys.