The hydrogenated (a-C:H) and hydrogen free (ta-C) films were tested in
sliding wear tests. The tests were carried out in air at room tempera
ture (RH 15+/-5%). The coefficient of friction in the tests was in the
range 0.03-0.12 for the a-C:H films and 0.17-0.28 for the ta-C films.
The wear volume of the DLC films was sufficiently low to enable the d
irect comparison of the film properties of the worn film to the origin
al film. The microstructure of the films after wear tests has been cha
racterized by micro RAMAN, the mechanical properties were measured by
nano indentation and the elastic modulus was measured with the laser-a
coustic method. No change of the micro structure of the DLC films was
observed. The observed reduction of the elastic modulus of the ta-C fi
lm is explained by the evolution of mechanical defects such as micro-c
racks and cracking at the nodular defects typical in non filtered vacu
um are depositions. (C) 1998 Elsevier Science S.A. All rights reserved
.