Adhesion and composite micro-hardness of DLC and Si-DLC films deposited on nitrile rubber

► DLC and Si-DLC films with and without Si-C interlayers are deposited on NBR. ► Deposition was by a closed field unbalanced magnetron sputtering ion plating system. ► An adhesion rating of 4 A for films with Si-C interlayer was achieved. ► Composite micro-hardness of 15.5 GPa was obtained for DLC films. ► The frictional increase is related to the composite micro-hardness of the films.