Deposition of Wear-Resistant Nanocomposite Coatings from Accelerated C60 Ions

Abstract

From accelerated C₆₀ ions at temperatures of 200 and 300°C hard wear-resistant carbon coatings were deposited. It has been established that the mechanical properties of the coatings are determined by the substrate temperature (T_s) and the energy composition of the beam. The hardness of coatings deposited from \({\text{C}}_{{60}}^{ + }\) ions with an energy of 7 keV exceeds 50 GPa and is practically independent of T_s. The presence of \({\text{C}}_{{60}}^{{2 + }}\) and \({\text{C}}_{{60}}^{{3 + }}\) with an energy of ~14 and 21 keV, respectively, in the beam leads to a result that is not typical for carbon coatings—the hardness increases by more than 1.3 times with an increase in T_s from 200 to 300°C (from 31.6 to 41.6 GPa). In this case, according to Raman spectroscopy data, the size of graphite nanocrystals in the coating increases with temperature up to almost 2 nm. Coatings obtained under conditions of irradiation with \({\text{C}}_{{60}}^{{2 + }}\) and \({\text{C}}_{{60}}^{{3 + }}\) ions are characterized by minimal wear (1.5 × 10^–8 mm³/(N m), T_s = 200°C) and minimal friction coefficient (μ = 0.05 for T_s = 300°C). We attribute the unusual dependence of hardness on T_s and the improvement in the tribological properties of coatings to the formation of a composite structure based on a diamond-like matrix and graphite nanocrystals in this T_s range.