Influence of bias voltage on the microstructure, mechanical and corrosion properties of AlSiN films deposited by HiPIMS technique

AlSiN films were deposited with various bias voltages ranging from 0 V to - 150 V by high power impulse magnetron sputtering (HiPIMS) technique. The effects of bias voltage on the microstructure, mechanical and corrosion behavior were investigated. The AlSiN films exhibited an over-stoichiometric N content and both cubic and hexagonal AlN were observed in films. All deposited films showed a typical surface feature of granular structure and the cross-sectional images exhibited that all films possessed columnar structure, which was changed from coarse columnar to denser columnar structure with increasing the bias voltage. The AlSiN film deposited at - 150 V possessed the densest structure and exhibited the best mechanical properties, including hardness, toughness and nano-wear resistance. The corrosion test showed that all coated samples had better corrosion resistance compared to SUS304 in 3.5 wt.% NaCl solution and the AlSiN film deposited at bias voltage of - 150 V possessed the best corrosion resistance due to denser microstructure, which could act as a barrier layer for blocking the diffusion of corrosive substances.