Synthesis and characterization of thin films of WCx, produced by mixing W and C plasma streams

WCx coatings have been synthesized by filtered cathodic are deposition at room temperature. Repetitively pulsed W and C plasma streams were mixed, and the duration of the pulse of each stream was used to vary the film composition. The energy of the incident ions was controlled by applying a pulsed bias voltage at the substrate, and was used for enhancing the adhesion as well as for modifying the microstructure of the film. The films with low W content (less than 20 at.%) consisted of regions of amorphous WC dispersed in an amorphous carbon matrix, At higher Ur content, nano-crystalline WC was observed. internal stresses in the as deposited films ranged between 500 and 4500 MPa, depending on the W content and the applied bias voltage. Film hardness varied between 63 GPa and 30 GPa, and strongly depended uh the W content and also on the applied bias voltage. (C) 1997 Elsevier Science S.A.