Abstract
Ti-Ni alloy films were prepared by RF sputtering on water-cooled aluminum substrates. It was anticipated that for metal substrates, the corrosion resistance of an amorphous film having a high corrosion resistance, would be changed by the roughness of the substrate surface, and by interdiffusion between the substrate and the coating layer. Accordingly we investigated the influence of the roughness of aluminum substrates and the diffusion of the coating layer and the substrate, on the corrosion resistance of coatings. The results obtained are as follows: 1) Films of 54 and 68 at.% Ti-Ni alloy on aluminum substrates were confirmed by X-ray diffraction and TEM analysis to be amorphous. 2) As the roughness of the aluminum substrate increased, the corrosion resistance of the coating was degraded significantly. Even for the coating that exhibited the best corrosion resistance in this experiment, a certain amount of aluminum as a substrate material was dissolved. This means that a Ti-Ni alloy coating of 1μm in its thickness dose not provide sufficient protection against corrosion. 3) After the coating layers were annealed at 500°C for 3 hours, interdiffusion with the substrate was found, and dissolution of titanium, nickel and aluminum increased slightly.
