Thermal stability of nonhydrogenated multilayer amorphous carbon prepared by the filtered cathodic vacuum arc technique

Abstract

Through discrete modulation of the deposition biasing conditions, multilayered nonhydrogenated diamondlike amorphous carbon films were prepared by the filtered cathodic vacuum arc technique. Films deposited under different conditions were divided into two groups in order to study how the modulation as well as sublayer content affect various mechanical and material properties as deposited and after annealing in vacuum. A 30% decrease in the residual stress of the multilayer films from 4.3to2.8GPa was observed with only marginal (5%) changes in the hardness. The frictional characteristics of the multilayer films were also studied and shown to be excellent, having a coefficient of friction of 0.1 and stable with annealing. A larger decrease in the resistance to wear was observed in multilayer films richer in soft sublayers which was linked to the decreased in sp3 content in the films.