Influence of heat treatment on the mechanical properties of layered carbon coatings

The influence of heat treatment modes on the mechanical properties of coatings based on carbon and composite nitride layers has been determined by the nanoindentation. An increase in the hardness of the (Al-TiN)/a-C coating to $19,7$ GPa after annealing in vacuum at $400^\circ$ C was established. The ratios $H/E$, $H^3/E^2$ were determined, which characterize the elastic properties of the coatings. An increase in the resistance to plastic deformation for coatings containing aluminum after heat treatment in vacuum has been established. The analysis of the elastic recovery coefficients $\eta_{IT}$ obtained at different indentation depths indicates the formation of a more homogeneous structure and a decrease in the gradient of mechanical properties along the thickness in comparison with unannealed coatings.