Thin films of Ta or Co- Cr- W deposited on 2Cr13 stainless steel were irradiated with 200 keV Xe+ or 190 keV N+ at room temperature. The results of electrochemical corrosion behaviour of the resulting films in H2SO4 solution show that the corrosion resistance is greatly improved compared with that of virgin steel. Energy dispersive X-ray analysis, Rutherford backscattering spectrometry and X-ray photoelectron spectrometry were used to determine the surface composition of the irradiated layers, and Ta depth profile and chemical states.