Enhanced Anti-Tribocorrosion Performance of Ti-DLC Coatings Deposited by Filtered Cathodic Vacuum Arc with the Optimization of Bias Voltage

Abstract

To improve the anti-tribocorrosion property, and decrease the metal dissolution and wear of stainless-steel components caused by the synergistic action of corrosion and friction in marine environments, Ti-DLC coatings were obtained on steel substrate using a filtered cathodic vacuum arc (FCVA) system by adjusting bias voltage. The structure, mechanical properties, corrosion, and tribocorrosion behavior were investigated. Increasing the bias voltage from −50 V to −300 V, Ti content decreased from 23.9 to 22.5 at.%, and grain size decreased first, and then increased. Obvious TiC grains embedded in the amorphous carbon matrix were observed in the coating from the TEM result. Hardness increased from 30.23 GPa to 34.24 GPa with an increase in bias voltage from −50 to −200 V. The results of tribocorrosion testing showed that the Ti-DLC coatings at −200 V presented the best anti-tribocorrosion performance with the smallest friction coefficient of 0.052, wear rate of 2.48 × 10−7 mm3/N∙m, and high open-circuit potential, which is mainly due to the dense structure, high value of H/E* and H3/E*2, and great corrosion resistance. Obtained results suggest that the Ti-DLC coating with nanocomposite structure is a potential protective material for marine equipment.