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 0.5 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.