Lubrication of Oxygenated Diamond-like Carbon Surfaces

Methods are provided for lubricating oxygenated diamond like carbon surfaces to reduce friction while reducing or minimizing wear on the surface. A diamond-like carbon surface layer having a surface ratio of oxygen to carbon of 1:15 or more can be lubricated using a lubricant oil that includes a molybdenum- based friction modifier additive, a tungsten-based friction modifier additive, or a combination thereof. The Mo-based friction modifier (and/or other friction modifier based on a Group VI metal) can be selected based on the Gibbs free energy of adsorption (AG) for the friction modifier on an oxygenated diamond-like carbon surface. Use of a Group VI metal-based friction modifier having a AG of adsorption with a sufficiently large magnitude can reduce friction at the surface of the oxygenated diamond-like carbon while causing a reduced or minimized amount of wear during lubrication.