Typical corrosion morphologies of Ni-Al intermetallics are dendritic-like and cater-like pits. Interdendritic corrosion and intergranular corrosion are proposed. The nonuniform distribution in composition and multiphase result in interdendritic corrosion and intergranular corrosion. The corrosion resistance are in the order of Ni:Al = 1:1 > Ni:Al = 3:1 > Ni:Al = 2:1.