Tribological and mechanical properties of aluminum containing tetrahedral amorphous carbon films

Tetrahedral amorphous carbon (ta-C) films which contained aluminum element were fabricated by filtered cathodic vacuum arc (FCVA) method. The tribological characteristics of the ta-C films were investigated with ball-on-disk tribometer. The increment of aluminum in the ta-C film leads to an increase of sp² carbon bonding and a decrease of sp³ fraction in the film. The roughness of the films was measured with atomic force microscope, and the hardness and Young's modulus of the films were measured with nanoindentation. The results showed that the film hardness and Young's modulus dropped with the increase of Al content in the films. The results have been interpreted with respect to the change of sp³ and sp² fractions in the ta-C:Al films.