  Ultrananocrystalline Diamond Nanowire (UNCD NW) thin film was deposited on
mirror polished silicon substrate (100) using Microwave Plasma Enhanced
Chemical Vapor Deposition (MPECVD) System with optimized deposition parameters
in CH4 (6%)/N2 plasma media. The film exhibited wire like morphology with
randomly oriented and homogeneously distributed ultranano diamond grains
separated by an interphase boundary of graphitic and amorphous carbon (a-C)
phases. Micro-tribological studies of film were carried out against Al2O3, SiC
and steel balls in ambient atmospheric conditions. Initially, the friction
coefficient was found to be high for UNCD NW/SiC and UNCD NW/Steel sliding
pairs which gradually decreased to low value. While, in UNCD NW/Al2O3 sliding
combination, the ultralow value of friction coefficient was maintained
throughout the whole sliding process. High wear resistant properties of the
film were observed in UNCD NW/SiC and UNCD NW/Steel pairs. In UNCD NW/Al2O3
case, ball counterbody showed negligible wear dimension. Such kind of
tribological behavior was attributed to the different type of mechanical and
chemical interactions of ball counterbodies with UNCD NW thin film.
