Friction of Microscale Contacts on Diamond-Like Carbon Nanocomposite Coatings

Microtribology of diamond-like carbon (DLC) nanocomposite coatings was studied using a commercially available nanoindentation system. Reciprocating sliding tests were conducted at 4 μm/s over track lengths of 8 μm with diamond and sapphire counterfaces with nominal diameters of 20 and 300 microns, respectively. Measured contact stresses were between 0.2 and 2.0 GPa for both tips. The friction behavior as a function of the contact stress was explored in the elastic regime. Measured interfacial shear stress for these sliding contacts were 12 ± 1 MPa for sapphire and 31 ± 3 MPa for diamond against DLC coatings.