Influence of heat treatment on the structure and mechanical properties of carbon coatings doped with zirconium and silicon

The structural features and mechanical properties of composite carbon coatings formed from plasma flows of complex composition generated by pulsed electric arc and spark evaporation in the presence of molecular nitrogen were investigated. The nitrogen concentration in the coating was varied by changing its partial pressure in the residual atmosphere of the vacuum chamber. It was found that nitriding of carbon coatings doped with zirconium and silicon at a nitrogen partial pressure of 0.08 Pa leads to an increase in dispersion, a decrease in their roughness and the size of individual structural formations. The features of chemical interaction processes were determined using X-ray photoelectron spectroscopy. Nitriding promotes an increase in the degree of structural ordering of sp 2 -clusters, the formation of compounds based on CN x , nitrides of alloying elements and an increase in the ratio of sp 3 /sp 2 -hybridized carbon atoms, which leads to an increase in the nanohardness of composite carbon coatings to 15.3 GPa. It has been shown that the formation of hard phases based on alloying element carbides and nitrides leads to increased friction coefficients and volumetric wear of the counterface during nitriding of composite carbon coatings. The chemical composition of the composite carbon coatings has been determined, providing an optimal combination of nanohardness and tribological properties due to the highest proportion of clusters based on Csp 2 –N-bonds, which are transformed during friction into graphite, which acts as a solid lubricant. The obtained results can be used to modify the surface of metalworking tools and specialized equipment parts in order to improve their mechanical characteristics and increase their service life.