Tribochemical effects of various gases and water vapor on thin film magnetic disks with carbon overcoats

Friction tests on thin film magnetic disks with carbon overcoats were performed using commercial read/write heads as sliders. The results provide evidence that the thin film overcoats wear through chemical means in the presence of gaseous oxygen, and through mechanical means in the absence of oxygen. When small concentrations of water are present, friction behavior resembling that of an oxidizing environment is observed, suggesting oxidation of the carbon film preceded by dissociation of adsorbed water. © 1991 by ASME.