Influence of Bias Voltage on Microstructures and Mechanical Behavior of Cr-Si-N Coatings

The Cr-Si-N coatings were synthesized by magnetron co-sputtering of Cr and Si targets on substrates of Si (100), Corning Eagle glass and 304 stainless-steel. The influence of the bias voltage on the microstructures and mechanical properties was investigated with X-ray diffraction,scanning electron microscopy,nano-indenter,residual stress analyzer and tribometer. The results show that the bias voltage has a major impact on the growth of Cr-Si-N coatings. To be specific, as the bias voltage varied from 0.0 to -50 V,the XRD peaks slowly shifted to smaller angle, possibly because of the lattice distortion induced by residual stress; the Cr-Si-N coatings became more compact and thinner, accompanied by a size reduction of columnar grains; the hardness rapidly increased from 12.4 GPa at 0.0 V to 35.5 GPa at -50 V;and the wear-rate changed in a weak decrease-increase mode, being the lowest at -10 V.