Dependence of Pin Surface Roughness for Friction Forces of Ultrathin Perfluoropolyether Lubricant Film on Magnetic Disks by Pin-on-Disk Test

Abstract

We fabricated supersmooth probes for use in pin-on-disk sliding tests by applying gas cluster ion beam irradiation to glass convex lenses. In the fabrication process, various changes were made to the irradiation conditions; these included one-step irradiation of Ar clusters or two-step irradiation of Ar and N2clusters, with or without Ar cluster-assisted tough carbon deposition prior to N2irradiation, and the application of various ion doses onto the surface. We successfully obtained probes with a centerline averaged surface roughness that ranged widely from 1.08 to 4.30 nm. Using these probes, we measured the friction forces exerted on magnetic disks coated with a molecularly thin lubricant film. Perfluoropolyether lubricant films with different numbers of hydroxyl end groups were compared, and our results indicated that the friction force increases as the surface roughness of the pin decreases and that increases as the number of hydroxyl end groups increases.

Study of 130 Mev Ni Ion Irradiation Induced Surface Modification of DLC Films Grown By Microwave Plasma CVD.

“…The wear resistance of the UHMWPE against a metal femoral head deposited with DLC by MPCVD showed better performance [6]. The surface of DLC can be modified on the nanometer scale using high energy ion irradiation [7] and self bias [8]. Ion irradiation has been used to produce a wide variety of modifications in different materials due to the energy loss of the ions as they travel through the material.…”

“…Modifications in DLC thin films by ion irradiation has been previously studied for changes in the properties [9,10]. Recently H. Tani et al [7] have reported that two step Ar-N2 GCIB irradiation has resulted in the reduction of surface roughness in DLC films. In this context it will be interesting to study the influence high energy ion irradiation on surface roughness of DLC films synthesized by microwave plasma CVD.…”