ION-IMPLANTED DIAMOND FILMS AND THEIR TRIBOLOGICAL PROPERTIES

This paper reports the physical characterization and tribological evaluation of ion-implanted diamond films. Diamond films were produced by microwave plasma, chemical vapor deposition technique. Diamond films with various grain sizes (0.3 and 3 mum) and roughness (9.1 and 92.1 nm r.m.s. respectively) were implanted with C+ (m/e = 12) at an ion energy of 160 eV and a fluence of 6.72 x 10(17) ions cm-2. Unidirectional sliding friction experiments were conducted in ultrahigh vacuum (6.6 x 10(-7) Pa), dry nitrogen and humid air (40% RH) environments. The effects of C+ ion bombardment on fine and coarse-grained diamond films are as follows: the surface morphology of the diamond films did not change; the surface roughness increased (16.3 and 135.3 nm r.m.s.); the diamond structures were damaged and formed a thin layer of amorphous non-diamond carbon; the friction coefficients dramatically decreased in the ultrahigh vacuum (0.1 and 0.4); the friction coefficients decreased slightly in the dry nitrogen and humid air environments.