Thin films containing yttrium were deposited on Ni-20Cr substrate surfaces by an aqueous electrochemical technique, called cathodic precipitation. After deposition, the samples were thermally treated to transform the deposited hydroxide into corresponding oxide and to improve the adhesion of the film to the metallic substrate. The influence of these thin solid films on the isothermal oxidation behaviour of a Ni-20%Cr-1.5%Si (wt%) alloy was investigated between 800degreesC and 950degreesC using several analytical techniques. The influence of silicon is also discussed.