The influence of growth defects in sputter-deposited TiAlN hard coatings on their tribological behavior

The wear of growth defects produced during magnetron sputtering and the subsequent tribological processes were systematically studied using ball-on-disk tests. The aim was to examine in detail the processes that occur between the surfaces coated with a hard coating and a typical tribological counter body. For this purpose a tool-steel substrate coated with TiAlN was subjected to a set of tribological tests in order to investigate the initial wear processes between different sliding pairs. As a counter body, either a hard alumina (Al2O3) or a softer 100Cr6 ball was used. The growth defects form the first contact between the adjacent surfaces; therefore, the study was limited to the running-in period of the cyclic sliding. Using SEM and FIB we followed the same group of defects after each cycle of tribological test to reveal the underlying wear processes.