Structure and mechanical properties of diamondlike carbon films produced by hollow-cathode plasma deposition

Diamondlike carbon (DLC) films are deposited on AISI 304 stainless-steel substrates using hollow-cathode chemical vapor deposition. The effects of the substrate bias on the structural and mechanical properties of the films are studied. X-ray photoelectron spectroscopy reveals the existence of CC (sp2) and C–C (sp3) functional groups in the films, and Raman spectra show that the ratio of the G (graphite) peak to the D (disorder) peak depends on the sample bias. The DLC film deposited at −50V bias has the highest sp3 content, and this is consistent with the G-band position and D-band full width at half maximum as a result of substrate biasing. The sample bias also has a critical influence on the thickness and hardness of the deposited films. The largest thickness (1700nm) and highest hardness (HV1099) are achieved at a bias voltage of −50V. All the films show low friction coefficients, and the sample treated at −200V gives rise to the lowest friction coefficient.