Friction and wear behaviour of pyramidal nanoscaled surface features

This study reports on the friction and wear behaviour of nanoscaled pyramidal surface features of chromium nitride thin films in relation to the dimensions of those features. The pyramidal features were created, and their size controlled, by PVD based in-process structuring. Microtribological tests analysed both the evolution of wear-induced surface alterations and the correlated evolution in the coefficient of friction as functions of normal load and duration of the loading. Results indicate that the severity of wear diminishes tremendously with increasing feature size when tested at the same normal load. So, wear-induced damage similar to that seen on surfaces with small-sized features was observed for the largest surface features tested only after a 100 times longer test duration. The less severe wear of the largest pyramids leads also to friction up to 75% lower compared to surfaces with the smallest features.