Structure and mechanical properties of a-C/(AlCrWTaTiNb)C_xN_y composite films

a-C/(AlCrWTaTiNb)C_xN_y composite films are deposited by a magnetron sputtering technique using a carbon and mosaic target. The effect of carbon target power on chemical composition, morphology, microstructure and mechanical properties of a-C/(AlCrWTaTiNb)C_xN_y composite films is investigated. It is found that a multi-element nitride (AlCrWTaTiNb)N_x film prepared without the carbon target demonstrates a triangle shape morphology with two-phase face-centred cubic structure (FCC). The crystallographic structure of the composite films changes into single-phase FCC and the morphology into granular when the carbon target power is in the range of 50–150 W. The preferred orientation of the composited films changes from (220) without the carbon target to (111) introducing carbon atoms. The maximum of micro-hardness and elastic modulus of a-C/(AlCrWTaTiNb)C_xN_y composite films deposited at 100 W carbon target power are 23 and 290 GPa, respectively. A corresponding H³/E² value reflecting film frictional characteristics also reaches a maximum of 0·147.