Investigation of the Mechanical and Tribological Properties of Diamond-Like Carbon Films on YG8 and High-Speed Steel Substrates with W Buffer Layers

To enhance the mechanical and friction properties of diamond-like carbon (DLC) films, DLC composite films with multiple W buffer layers were deposited on metal substrates (cemented carbide, high-speed steel) by a hybrid deposition technique combining a novel linear ion beam source and a DC magnetron sputtering process. Experimental tests were conducted to assess the structure, mechanical, and frictional behavior of the films. The results indicate that DLC/substrate combination achieves a hardness of 29 GPa, and the hardness of substrate significantly influences its adhesion and frictional performance. As the substrate’s hardness decreases, the composite hardness of DLC/substrate and the adhesion of Lc3 also decrease. Friction tests conducted in both dry and oil environments reveal that the DLC films exhibit a higher friction coefficient on the substrates, and this value becomes lower as the hardness of the substrates decreases. Notably, the DLC film with a W buffer layer deposited on YG8 demonstrates exceptional frictional properties. In both dry and oil environments, it exhibits a reduction in the coefficient of friction from 0.14 in dry conditions to 0.08 in oil. Additionally, the wear rate in oil conditions is measured at 2.1 × 10⁻⁸ mm³/(N m).