Diamond-like/graphite-like carbon composite films deposited by high-power impulse magnetron sputtering

Diamond-like carbon (DLC)/graphite-like carbon (GLC) composite films were prepared with high-power impulse magnetron sputtering (HiPIMS) using a mixture of Ar and Ne as the sputtering gas. The effect of the Ne fraction in the sputtering gas on the surface morphology, carbon bonding structure, microstructure, mechanical properties, residual stress, and tribological performance of the deposited films were characterized using laser scanning confocal microscopy, Raman spectroscopy, nano-indentation, residual stress tester, and friction and wear testing using a ball-on- plate tribometer, respectively. The films have a composite surface structure consisting of sp(2)-rich GLC microparticles embedded in an sp(3)-rich DLC matrix. Both components can be controlled to some degree by varying the Ne fraction. Specifically, as the Ne fraction is increased, both the number and size of the GLC microparticles decreases, while the sp(3) content increases. The GLC microparticles in the film can reduce the real contact area in friction testing, decreasing the friction coefficient, while the sp(3)-rich DLC phase enables the high hardness and wear resistance of the films. By adjusting the Ne fraction during the HiPIMS process, DLC/GLC composite films with low friction and high wear resistance can be generated.