Behavior of perfluoropolyether in particulate magnetic recording media

In order to achieve the required frictional properties in the particulate media, the adequate amount of surface lubricant is investigated. By using newly-synthesized perfluoropolyethers (PFPEs) in particulate media, the amount of surface lubricant is evaluated by X-ray photoelectron spectroscopy (XPS) and contact angle measurements. It is necessary for friction reduction to have not only large coverage ratio of the outer most surface by lubricant but also a sufficient amount of sub-surface lubricant. In comparing internal and topical lubrication, the topical coated media have larger coverage ratios that lead to lower friction coefficients. The migration rate of the lubricant is evaluated as the recovery rate of the XPS peak height. Lubricant of higher recovery rate has better stability with regard to friction in storage of the tape under accelerated conditions