Possibility of Organic Monolayer Films as Lubricants for Disk Drives: Comparative Study of PFPE and Organosilane

Abstract

Organosilane monolayer of 1H,1H,2H,2H-perfluorodecyltrichlorosilane and PFPE lubricant films were deposited on magnetic hard disk surfaces protected with amorphous carbon overcoats, and their frictional properties were investigated by a ball-on-flat tribotester. The thickness of PFPE films having only an immobile layer or both immobile and mobile layers was varied from about 0.6 nm to 4 nm. The friction coefficient of the organosilane monolayer coated surface is comparable to that of the PFPE coated surface with a 1.0 nm thick immobile layer and lower than that of the PFPE coated surface with a 0.6 nm thick immobile layer. The thickness of the lubricant has to decrease to less than 1 nm to further increase recording density. In that case, the mobile portion of PFPE lubricant is negligible. This study suggests that organosilane monolayers (with shorter chain lengths) may be used as an alternate lubricant in hard disk drive systems.