Microstructure modifications of CrN coatings by pulsed bias sputtering

This paper investigates the influence of a combined electron and ion bombardment via asymmetric bipolar pulsed substrate bias on the microstructure and mechanical properties of reactively magnetron-sputtered CrN hard coatings for two different ion-to-atom flux ratios. A short ratio of electron-to-ion bombardment duration leads to a preferred (110) orientation of the CrN phase, high residual stress up to -4.1 GPa and hardness values up to 17.9 GPa. An increased electron-to-ion bombardment ratio promotes a change in preferred orientation from (110) towards (100). Concurrently, residual stress and hardness values are reduced to a few +/- 100 MPa and 15.1 GPa, respectively. The texture cross-over from (110) to (100) is shifted to longer electron bombardment duration for higher ion-to-atom flux ratios. (c) 2012 Elsevier B.V. All rights reserved.