Abstract
Amorphous Ni-Mo-W ternary alloy films were prepared by electrodeposition from a citric acid bath and their corrosion resistance was investigated by electrochemical measurement. The crystal structure of the films was influenced by the pH of the bath rather than the cathodic current density; The amorphous films were obtained between pH2.5 and 4.0. The Mo content of the amorphous films was about 20wt% or more. Their corrosion resistance was better than that of crystalline films. Electrochemical impedance spectroscopy and scanning electron microscopy showed the surfaces of the amorphous films to be flatter and more compact than those of crystalline films. This study suggests that the effective corrosion resistance of alloy films is based on the homogeneity of the surface.
