Paper IS+NC-ThA5
Investigating Sliding-induced Graphitization of Diamond-like Carbon Films by In Situ TEM

Thursday, October 23, 2008, 3:20 pm, Room 310

The field of tribology - the study of contacting surfaces in relative motion - has long suffered from the problem of buried interfaces, forcing researchers to conduct experiments completely blind to the underlying mechanical deformation and structural processes that dictate friction behavior. Using a unique in-situ TEM nanomanipulation technique, we can dynamically observe the sliding interface at the single asperity level.¹ With this method, we can deeply probe the effects of film composition on surface behavior and by extension, on the tribology and wear properties of such films. In particular, we are interested in the precise mechanisms of graphitization seen in diamond-like carbon films.² The bonding configuration at the surface has been shown to play a significant role in nanotribological properties, along with experimental and growth parameters such as the relative amount of hydrogen present at the surface.³ By using electron energy loss spectroscopy combined with high resolution imaging, we can observe the changes in bonding that occur during graphitization as they happen. We study the results over a range of films with differing levels of hydrogenation.

¹ A P Merkle and L D Marks. "Friction in Full View." Applied Physics Letters 90, 064101 (2007).
² Y Liu, A Erdermir, and E I Meletis. "A study of the wear mechanism of diamond-like carbon films." Surface and Coatings Technology 82 (1996) 48-56.
³ A V Sumant, et. al. "Surface chemistry and bonding configuration of ultrananocrystalline diamond surfaces and their effects on nanotribological properties." Physical Review B 76, 235429 (2007).