EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

Despite a great industrial demand for superhard (hardness > 40 GPa) and on the same time tough thin films with high thermal stability (T > 1000°C) such films can currently not be synthesized. By combining the material strategy of HEA nitrides with the design concepts of nanostructured thin films it is assumed that new horizons in the combination of the aforementioned criteria can be achieved.

In the current work preliminary results for the synthesis of various refractory type HEA nitride system thin films by means of arc deposition technique are presented. The deposited films were thoroughly characterized by means of structural analysis (SEM, TEM, EDS, XRD). The results of the structural analysis reveal that all nitride thin films exhibit a single phase fcc structure with more or less strong columnar growth. In some cases this columnar growth can be suppressed by the application of bias voltages to the substrate.

To compare the toughness and wear resistance of the HEA nitride coatings with more industrially established hard coatings scratch tests were performed on promising HEA nitride systems and the damaged area below the scratch was analyzed by means of FIB cross sectioning. Furthermore bending tests on coated substrates were performed and the early damage evolution was analyzed by means of acoustic emission measurements.

The basic screening tests with regard to the mechanical properties could demonstrate that re-fractory type HEA nitride thin films are promising candidates for wear protection under severe conditions.