Influence of Bias Voltage on Microstructure and Properties of TiAlSiN Coatings Prepared by HiPIMS

Abstract

For investigating the influence and mechanism of bias voltage on the composition structure, mechanical properties and tribological properties of TiAlSiN coatings prepared by high-power pulsed magnetron sputtering(HiPIMS), TiAlSiN coatings were deposited on YG8 hardness alloy and N-type single crystal (111) Si by HiPIMS technology with regulating substrate bias voltage (0～－200 V).The microstructure,composition characterization and performance testing of TiAlSiN coatings were carried out by scanning electron microscopy (SEM),X-ray diffraction (XRD), electron probe microscopy (EPMA), X-ray photoelectron spectroscopy (XPS), ultra depth of field microscopy, white light interferometry, nanoindentation, scratch and reciprocating friction and wear testing machines.Results showed that in terms of HiPIMS discharge behavior, an increase in bias voltage could increase the HiPIMS ignition voltage, but the impact on the discharge voltage and current during the platform stage was not significant.The relative changes in elemental composition of TiAlSiN coatings prepared under different bias conditions were relatively small.As the bias voltage increased, the TiAlSiN coating changed from hcp-(Ti, Al)N＋fcc-(Ti, Al) N to fcc-(Ti, Al)N.In addition, as the bias voltage increased, the cross-sectional structure of the coating transformed from a loose columnar crystal structure to a dense stacked structure without obvious defects, with surface nodular defects disappearing and grain size gradually decreasing.In terms of mechanical properties, with the increase of bias voltage, the hardness and adhesion of TiAlSiN coating exhibited an upward trend.The coating prepared at－200 V achieved optimal performance, with a maximum hardness of 26.19 GPa and a maximum H/E* of 0.099 5.When the bonding force reached a maximum of 19.63 N,the coating had the lowest wear rate,which was 9×10－15 μm3/(N·m).Based on the above analysis, the microstructure and properties of the coating could be controlled by changing the substrate bias voltage during HiPIMS process, which also improved the toughness of the coating and enhanced the adhesion and tribological properties of the coating significantly.

Keywords

• tialsin coatings;high power impulse magnetron sputtering;substrate bias voltage;microstructure;mechanical properties