Uncovering the Physical Basis Connecting Environment and Tribological Performance of Ultrananocrystalline Diamond

摘要

The researchers have studied the nano-scale mechanical and tribological properties of ultrananocrystalline diamond (UNCD), which is a thin- film material known to have extremely high strength and excellent tribological properties, namely low friction, adhesion, and wear, at macroscopic scales. They have successfully grown UNCD films in house and characterized their composition and structure. They have measured the surface chemical properties of these samples as well as commercial UNCD samples from their collaborator, Advanced Diamond Technologies Inc. Measurements demonstrate the expected carbon- rich composition but with measurable amounts of surface-bound contaminants. They also performed TEM observations to investigate the grain structure of commercial UNCD films, verifying a nanoscale grain size. They worked with collaborators from UPenn on in-situ TEM nanoindentation methodology and obtained preliminary results characterizing the adhesion and wear behavior of computational nano-scale UNCD asperities, verifying extremely low wear particularly in comparison to Si.