Tribological fundamentals of polycrystalline diamond films

A decade's worth of SEM-tribometric work on polycrystalline diamond films i s reviewed. Diamond-coated Si and SiC specimens have been tested under osci llatory sliding, at temperatures from room ambient to 1000 degrees C in (a) similar to 1.33x10(-3) Pa (similar to 1 x 10(-5) Torr) vacuum, (b) 13-39 P a (0.1-0.3 Torr) partial pressures of hydrogen and (c) 26 Pa (0.2 Torr) par tial pressure of oxygen. The temperature- and atmosphere-controlled tribolo gical behavior of the films is interpreted by the environment-dependent val ues and trends of the average coefficient of friction. Accurate interpretat ion of the results is assisted by similar friction and wear data on various silicon crystallinities, complemented by applicable thermal desorption, su rface chemical and tribometric data taken from the literature. (C) 1999 Els evier Science S.A. All rights reserved.