PURPOSE: To obtain an Ni-base alloy excellent as the electrode for a spark plug by regulating specific wt. ratio of Cr, Si, Mn, Al and the balance Ni as alloy components and specifying the ratio of Si to Cr.
CONSTITUTION: As alloy components, by weight, 0.5 to 3% Cr, 0.3 to 2.5% Si, >0.5 to <1.8% Mn, >0.05 to 2.5% Al and the balance Ni with inevitable impurities are regulated. Then, the ratio of Si to Cr (Si/Cr) is regulated to <1.1. The alloy has excellent heat resistance and corrosion resistance and furthermore has excellent workability.