Study on ultraviolet radiation effects on bonding interactions between lubricants and diamond-like carbon overcoat

• Main Author: Shi, Gladys Yuhui.
• Other Authors: Long, Yi
• Format: Final Year Project
• Language: English
• Published: 2009
• Subjects: DRNTU::Engineering
• Online Access: http://hdl.handle.net/10356/15415
• Institution: Nanyang Technological University

Pushing recording density towards even more data storage per unit area and beyond requires reducing flying height to 2.5nm-3nm or below. This raises tribology issues regarding the head disk interface (HDI) and prompts for urgent solutions. In this research project, the emphasis is placed on using Ultraviolet (UV) effects to improve bonding interactions between lubricant and Diamond-Like-Carbon (DLC) coating. Disks used in this research project were fabricated with Filtered Cathodic Vacuum Arc (FCVA) for DLC overcoat and dipped-coating technique for perfluoropolyether (PFPE) lubricant applications. Various characterization techniques such as gliding test, goniometry and optical surface analyzer (OSA) are employed to understand the interaction between lubricants and DLC coating. UV irradiation duration time, bonding interaction effects of UV irradiation on five PFPE lubricants with different end groups, surface energy calculation via contact angle measurements and spreading characteristics of one lubricant, specifically, ADOH was investigated. Glide testing was also done to test for ‘flyablilty’ of 4nm lubricant thick disk with effect of UV. UV irradiation is proved to be an effective method to enhanced the bonding interactions between the lubricant and DLC overcoat, which can in turn explore the ‘flyability’ of disks at lower flying height and hence increase the data storage capacity of Hard Disk Drives (HDD).