External Electric Field Assisted Ultraviolet Irradiation for Bonding of Lubricant Film on Magnetic Disks

In this paper, we sought to determine if, during ultraviolet (UV) exposure, the external electric field could control the bonded lubricant thickness. During UV irradiation, the effect of the external electric field on both the bonded lubricant thickness and surface free energy was studied. The lubricant films after UV irradiation were analyzed using time-of-flight secondary ion mass spectroscopy (TOF-SIMS). Because of the negative electric field, the polar component of the surface free energy was reduced, while the bonded lubricant thickness increased. Based on the results of the TOF-SIMS analysis, we concluded that these findings resulted from the negative electric field accelerating the photoelectron emission, and because of these photoelectrons, the bonding between the end groups and diamond-like carbon surface increased.