Abstract:TiCN films were deposited on AISI 304 stainless steel substrate by combining multi-arc ion plating and magnetron sputtering technique with ionizing titanium and graphite targets in an Ar+N2 mixture gas. The effect of duty ratio on the microstructure and corrosion resistance performance of TiCN films in a NaCl 3.5 wt.% solution was investigated. The results show that the as-deposited films reveal smooth, uniform and dense morphologies, mainly forming a fcc-TiN type structure with Ti-(C,N) bond as well as few a-CNx, and presenting (111) preferred orientation with the increase of duty ratio. TiCN films display a better resistance to corrosion than the bare substrate, as the duty ratio increased, the corrosion resistance property is enhanced gradually. When the duty ratio is 40%, the TiCN film shows the optimal one with a corrosion current density (icorr) of 3.262×10-7 A.cm-2 and a polarization resistance (Rp) of 238.4 kΩ.cm2, respectively. Electrochemical impedance spectroscopy (EIS) of the films also indicate that the penetration behavior of corrosive ions and the local corrosion process are two key factors affecting the electrode corrosion reaction kinetics process, which is in agreement with the polarization curves analysis results.