The diamondlike carbon (DLC) films were prepared on the surface of 304 stainless steel by plasma enhanced chemical vapor deposition (PECVD) technique with varying pulse bias voltages.The surface roughness,the crosssectional morphology,the structure and composition of the films were characterized by surface profilometer,scanning electron microscopy,Raman spectrum and electron probe,respectively.The hardness and elastic modulus of the films were tested on a nanoindentor,and the corresponding adhesion forces between the film and substrate were investigated using a scratch tester.The tribological properties of the films were evaluated by a ballondisc tribometer.The results show that the DLC films are successfully prepared by PECVD technique and the applied pulsed bias voltages greatly affect the morphologies,microstructures and mechanical properties of the asprepared DLC films.With the increasing of the bias voltages,the surface roughness,friction coefficient and wear rate of the DLC film are decreased to a minimum value and then start to increase,while the adhesion force between the film and the substrate is increased to a maximum value and then slightly decreased.The film prepared with 20 kV pulse bias voltage exhibits optimal adhesion force to the substrate.However,the film prepared with 16 kV bias voltage shows the smoothest surface and the highest hardness,resulting in superior friction reduction and wear resistance.