| AVS 56th International Symposium & Exhibition | |
| Tribology Focus Topic | Wednesday Sessions |
| Session TR+SE-WeA |
| Session: | Advances in Surface Engineering for Friction and Wear Control |
| Presenter: | C.M. Mate, Hitachi San Jose Research Center |
| Correspondent: | Click to Email |
Tremendous progress has been made over the past several decades towards understanding the nanoscale origins of tribological phenomena [1], leading to numerous breakthroughs in friction and wear control. The impact of these breakthroughs has been particularly striking in the disk drive industry, where improved tribological engineering of the head-disk interface has led to the magnetic spacing being reduced from ~100 nm in 1995 to ~10 nm in 2009, enabling a 103 increase in storage areal density. In today’s drives, recording head sliders fly reliably at incredibly small clearances (~2 nm during read-write operations) for many years at speeds > 10 m/s. As the industry moves to even smaller spacings, however, head-disk contact will become more frequent and improved surface engineering to control friction and wear will become more paramount.
In this talk, I will first review the key surface engineering features (slider air bearing surface, disk topography, overcoat, lubricant, etc.) that enable today’s disk drive sliders to fly at nanometer clearances over disk surfaces. I will then describe work going on in our laboratory both to determine the nanoscale origins of friction and to use this understanding to develop future head-disk interfaces that are expected to run in continuous contact.
To determine the nanoscale origins of friction at high-speed sliding contacts (> 1 m/s), we have developed a high shear rate apparatus using technology from the disk drive industry [2]. With this new instrument, friction, adhesion, and wear can be studied at high sliding speeds (1 to 100 m/s) for nanometer thick lubricant films sandwiched between atomically smooth surfaces. Recently, this instrument has been modified to incorporate optical microscopy for in-situ visualization when a slider runs in contact with a transparent rotating disk. This technique has been particularly useful for studying the formation of nanoscale, non-equilibrium menisci at high speed contacts.
[1] C.M. Mate, Tribology on the Small Scale: A Bottom up Approach to Friction, Lubrication, and Wear, Oxford University Press, Oxford, 2008.
[2] C. M. Mate, R.N. Payne, Q. Dai, K. Ono, Phys. Rev. Lett. 97 (2006) 216104.