Effect of electric currents on tribological behaviors of Ti/MoS2 composite film sliding against aluminum

Abstract

For MoS2-based films, mechanical performance has a significant influence on their tribological properties. In this work, Ti was doped into MoS2 film to enhance the mechanical properties, and the tribological properties and contact voltages of the Ti/MoS2 composite film sliding against Al balls were systemically investigated at different current conditions. It was found that the Ti/MoS2 film exhibited amorphous structure with a dense morphology, and the hardness, elastic modulus and toughness as well as adhesion strength were effectively enhanced with the incorporation of Ti into MoS2 film. It was also found that the Ti/MoS2 film showed better tribological properties than the MoS2 film under electric currents, which was attributed to the enhanced mechanical properties. What’s more, the abrasive wear and adhesive wear were the main failure types of the Ti/MoS2 film. When the currents were equal to or greater than 0.5 A, arc ablation appeared on the wear surfaces, and the main wear mechanisms were friction wear, arc erosion and the coupling effect. The contact voltages increased from low to high in the initial stage and dropped in the later stage.