Tribological Properties of DLC Films Against Aluminum Alloys Under Dry Friction Test

The objective of this research is to study the influence of the coating film on tribological properties under a dry friction test. DLC, Si-DLC, Si-N-DLC, and F-DLC were prepared from C2H2, C2H2:TMS, C2H2:TMS:N2 and C2H2:CF4 gaseous mixture by Plasma-based ion implantation (PBII) technique, on silicon wafer substrate at a film thickness of 500 nm. The structure of the films was analyzed by Raman spectroscopy. The hardness and elastic modulus of films were measured by nano-indentation hardness testing. The tribological properties of the films were measured using a ball-on-disk friction tester. A dry sliding test was carried out using a ball indenter, AISI44°C (diameter of 6.0 mm) under a normal applied load of 1, 2, and 3 N, the linear speed of 31.4 mm/s, and 3,000 frictional rotations. The results found that Si-DLC and SiN-DLC had a lower friction coefficient than F-DLC and DLC, due to higher film hardness. Moreover, with increasing fluorine content (F-DLC), the friction coefficient increases, while the increasing silicon (Si-DLC), and silicon-nitrogen contents, the friction coefficient decreases. This is due to the formation of transfer films on the interface. Additionally, Si-DLC films at silicon content of 14.2 at.% shows the lowest friction coefficient of 0.13.