Tribochemical wear on amorphous carbon thin films

Some physico-chemical processes taking place at a sliding CaTiO ₃-ceramic/unlubed carbon-film interface of a rigid disk drive are described. A major cause of frictional buildup is the tribochemical wear of the carbon surface atoms in the oxygen-containing atmosphere. Based on indirect evidence, a mechanism involving oxygen chemisorption on surface dangling bonds and CO/CO₂ desorption under the sliding motion of the read/write head is proposed. Raman data providing evidence of the formation of a graphite transfer film at the interface of some carbon films are shown. Catalytic activity of the slider ceramic towards oxidation is also demonstrated. Methods for slowing down the frictional-buildup process are discussed. They include heavier texture, carbons with higher sp³/sp² ratio, active sites blocking, and application of topical lubricant