Influence of working pressure on structure and properties of diamond-like carbon films

The diamond-like carbon(DLC) films were prepared by plasma-enhanced chemical vapor deposition(PECVD) with CH4 as the gas at different working pressure, on substrates of 316L stainless steel. The microstructures and properties of the films were characterized with Raman spectroscopy, scanning electron microscopy, nano-indenter and tribo-test. With the increase of working pressure from 7 Pa to 15 Pa, the sp3 content and mechanical properties of the films increased and the tribological properties decreased obviously. However, with the increase of working pressure from 15 Pa to 31 Pa, the sp3 content and mechanical properties of the films decreased and the tribological properties increased obviously.