Tribological properties of DLC films deposited under various conditions using a plasma-enhanced CVD

Diamond-like carbon (DLC) films were deposited on Si wafer by a plasma CVD deposition system using different substrate bias voltage. At the same time, Ar- and N-incorporated DLC films and DLC multilayer films were also prepared. The effects of deposition parameters, Ar, N and multilayer structure on tribological properties of the DLC films were investigated systematically. The friction and wear properties of the DLC films deposited under various conditions were measured in different environments (N-2, vacuum, O-2, dry air), respectively. For the DLC films deposited with different bias voltages, the wear resistance of the films decreased when the substrate bias increased. For the Ar-DLC films sliding in an N-2 environment, an extremely low friction coefficient of 0.04 and a wear rate of 10(-10) mm(3) /N m could be obtained. For the N incorporated DLC films, the excellent wear resistance, in the level of 10(-9)-10(-8) mm(3) /N m, can be observed in N-2, vacuum and dry air environments. By comparison to DLC film, the multilayer structure has little influence on the friction coefficient of the multilayer films. However, an environment insensitive DLC multilayer film with excellent wear resistance, in the level of 10(-8) mm(3) /N m in different environments (dry air, O-2 and vacuum), is obtained for a DLC multilayer film with optimized sub-layer thickness. (C) 2004 Elsevier Ltd. All rights reserved.