Durability and tribological performance of smooth diamond films produced by Ar-C60 microwave plasmas and by laser polishing

In this study, we explored and compared the friction and wear performance of smooth (30 nm, root mean square) and nanocrystalline diamond films (average grain size approximate to 15 nm) grown in an Ar-C-60 microwave plasma with the friction and wear performance of laser-polished microcrystalline diamond films (grain size approximate to 20-50 mu m) grown in a conventional CH4-H-2 microwave plasma. Tribological tests were run under 2-N load in open air (30-50% relative humidity) and in dry N-2. The frictional performances of both the as-grown smooth and laser polished diamond films were comparable. They both afforded very low friction coefficients (0.06-0.15) and low wear rates (2-6 x 10(-7) mm(3)/N.m) to counterface Si3N4 balls. We used Raman spectroscopy, electron microscopy, and atomic force microscopy to ascertain the structural, chemical, and surface topographical characteristics of the films and correlated the results with the friction and wear mechanisms of diamond films in open air and dry N-2. (C) 1997 Elsevier Science S.A.