Feasibility Study of Using DLC Coating in Conjunction with Laser Ablation process to Improve the Tribological Performance of an Engineering Surface

Increasing demands such as low friction, low wear rate, and long life-time have reached the limits of single DLC coatings. In order to meet the requirements, we propose to use an integrated approach to improve the wear property of an engineering surface. Firstly, dimples are introduced perpendicular to an engineering surface by a Nd:YAG laser emitting at 1064 nm. Subsequently, solid lubricant DLC is prepared on the patterned surface by magnetron sputtering technique. The effect of dimple densities from 7% to 45% on tribological properties of the coating surface was revealed. The wear performance of the textured DLC surfaces was studied by a pin-on-disk reciprocating sliding wear tester under boundary lubrication and dry conditions. The results showed that the DLC coatings with appropriate dimple densities have an obvious improvement on wear performance in term of friction coefficient, wear rate and wear life, as compared to un-textured DLC coatings. In boundary lubrication conditions, the improved wear performance can be explained by the promotion of reservoirs to enhance lubricant retention during sliding. In dry condition, the dimples trap wear particles and leave a free interface between pin and sliding contact surface, and avoid the surface worn by abrasive manner, thereby improving the wear performance of the DLC coating.