Friction Decomposition Reaction of Lubricant Oils Used for HDD and Chemical Effects of Slider Surfaces: Chemical Analysis by TOF-SIMS

摘要

Surface reactions on magnetic recording disks have been studied using our sliding test machine with ceramics slider under high vacuum conditions. Chemical changes of perfluoropolyether (PFPE) lubricant oils in the wear track were oh-served by time of flight secondary ion mass spectroscopy (OF-AIMS). It was found that lubricant oils were decomposed even under very low loads less than 1 aN. The decomposition reaction was affected by the coating materials such as Al_2O_3, diamond like carbon (DLC), TiN or c-BN on the slider. Lubricant oils reacted also with A1_2O_3 and TiN slider surfaces. Metal (Al, Ti) fluorides were detected by OF-AIMS in the sliding track after friction experiments. Material transfer is comfirmed by chemical wear of the slider material. The decomposition of lubricant molecules was initiated at the end group of molecules. On the other hand, DLC and c-BN sliders suppressed the decomposition of oil. With these materials, chemical wear was not observed. In conclusion, hard and chemically inert materials are suitable to develop a long-life head-disk interface.