The role of disk carbon and slider in water adsorption

Water adsorption was measured on carbon overcoated, thin film magnetic recording disks and magnetic recording heads. Measurements were made using an ellipsometer with a humidity chamber mounted on the sample stage. Water adsorption is dependent primarily on the hydrogen content of the carbon overcoat, for both lubed and unlubed disks. Water adsorption is independent of the lube type and thickness, except when the carbon overcoat has a low hydrogen content. In the latter case, water adsorption depends on the functional endgroup of the lube and slightly on lube thickness. Water adsorption on magnetic recording heads depends both on the head composition and surface roughness