Microstructure and mechanical properties of Ti-Al-Cr-N films: Effect of current of additional anode

Ti-Al-Cr-N films were fabricated on the surface of Si (100) wafers and M2 high speed steel by electrically enhanced discharge cathodic arc technology. The effect of the current of additional anode on plasma discharge, microstructure, hardness and adhesion strength has been investigated systematically. The results show that the discharge of additional anode can improve substrate current distinctly and mainly affects the excitation and ionization of nitrogen, rather than that of metal. Besides, the enhanced discharge can increase the ratio of substrate ion current to thickness of films (E_bi). The Ti-Al-Cr-N film deposited at the current of additional anode of 30 A possesses the highest nanohardness (31.3 GPa), the best adhesion strength between film and substrate (HF1), and the maximum H/E^⁎ and H³/E^⁎2 of about 0.081 and 0.25, respectively. Further increasing the current of additional anode to 40 A, the properties would deteriorate due to the precipitation of w-AlN (wurtzite structure) induced by ion irradiation effect.