Structural, mechanical and tribological properties of diamond-like carbon films prepared under different substrate bias voltage

Abstract

Diamond-like carbon (DLC) films were deposited on Si wafer by a plasma CVD system in different substrate bias voltage. The influence of bias voltage on structural, mechanical and tribological properties of the DLC films was investigated. The friction and wear properties of the DLC films in different environments (N 2, vacuum, O 2, dry-air and high moist air) were measured, respectively. As the substrate bias voltage increased from −1 to −3 kV, the sp 3 C and H concentrations of the DLC films decreased, the hardness and internal stress decreased, and the critical load increased. For the tribological properties of the DLC films, the friction coefficient of the films was not affected significantly in the inert environments (N 2 or vacuum), but decreased slightly in the reactive environments (O 2 or high moist air) when increased the substrate bias voltage. However, the wear resistance of the DLC films decreased obviously in different environments when increased the substrate bias. The correlation between the structure, mechanical and tribological properties of the DLC films was presented.