Structure, mechanical, tribological properties and corrosion resistance of C/N dual doping Mo-S-C-N films

Abstract

Transition metal dichalcogenides (TMDs) show poor mechanical properties and weak corrosion and oxidation resistance in ambient atmosphere, which results in the limit application and the lower work life. Doping TMDs based films with the enhanced performance show the potential to apply in harsh environment. The C/N dual-doping Mo-S-C-N films were deposited by magnetron sputtering, and the evolution of alternative microstructure composed of TMDs phase and amorphous inclusions was analyzed. The enhancement on mechanical, tribological and anti-corrosion properties of films with C/N dual-doping were evaluated. The strengthened TMDs phase and inclusions with MoCx/MoNx hard phase result in the improvement of mechanical properties (hardness 8.57–19.09 GPa). The superior tribological performance was obtained from film with 10.67 at. % of C and 17.36 at. % of N (wear rate 8.24 × 10-7 mm3/Nm, average friction coefficient (CoF) 0.188) and film with 14.87 at. % of C and 15.02 at. % of N (wear rate 8.02 × 10-7 mm3/Nm, average CoF 0.166). The balance between the effect of lubricating phase and mechanical performance strengthen by C/N dopants were achieved in these two films. The passivation of reactive sites in MoS2 leads to the improvement of corrosion resistance, while excessive dopants induce more pathways for corrosive medium, which leads to the corrosion failure of films.