Research Article Effect of HPPMS Pulse-Frequency on Plasma Discharge and Deposited AlTiN Coating Properties Stefanie Severin, 1 Muhammad Naveed, 2 and Sabine Weiß 1 1 Department of Physical Metallurgy and Materials Technology, Brandenburg University of Technology (BTU) Cottbus-Senfenberg, Konrad-Wachsmann-Allee 17, 03046 Cottbus, Germany 2 B¨ uhler Leybold Optics GmbH, Siemens Straße 88, 63755 Alzenau, Germany Correspondence should be addressed to Stefanie Severin; severste@b-tu.de Received 23 June 2017; Revised 20 September 2017; Accepted 3 October 2017; Published 14 November 2017 Academic Editor: David Holec Copyright © 2017 Stefanie Severin et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Coatings like TiAlN (titanium content more than 50%) or AlTiN (aluminium content more than 50%) are well established as hard and wear-resistant tool coatings, ofen prepared by physical vapour deposition (PVD) like arc evaporation or direct current magnetron sputtering (dcMS). With increasing challenges of operating conditions, there is a constant need for improvement of mechanical properties to withstand extreme loading conditions. Tis can be obtained by a higher amount of ionized sputtered metal atoms during the deposition process. To increase the metal ion fux a high-power pulse magnetron sputtering (HPPMS) was developed. In order to understand the relation between HPPMS process parameters and mechanical properties of the AlTiN coatings, the present study discusses how diferent pulse-frequencies (for a constant pulse length) infuence AlTiN coating structure growth and their mechanical properties. In addition, flm deposition rate and phase formation are infuenced by altering process parameters like pulse length and frequency. Hence, diferent pulse-frequencies produce specifc coatings with corresponding properties for functional requirements. Based on the established fndings, answers to new scientifc queries along with the demand to further optimize these coatings for tool applications are required. 1. Introduction Transition-metal nitrides are ofen used as wear-resistant or super hard coatings for enhancing the lifetime of cut- ting and forming tools [1–4]. A well-known hard coating is Al  Ti −1 N ( = 0.6), deposited by dc-magnetron/arc sputtering, which ofers an increase in component life due to high hardness and resistance against wear, corrosion, and oxidation at high temperatures [5–11]. With increas- ing challenges of operating conditions, a constant need in improvement of material properties is required to withstand extreme loadings. Tese properties can be achieved with smoother and denser coating structures resulting in better mechanical properties. A possibility of improving the flm quality is to increase the number and the energy of ionized sputtered atoms, which is not possible with conventional dc coating processes. Hence, High Pulse Power Magnetron Sputtering (HPPMS) technology is introduced during the recent decade allowing higher ion densities and energies in comparison to conventional coating methods. Te HPPMS is a further development of dc-magnetron sputtering, where a pulsed direct current power supply is used to ignite the plasma discharge in specifc intervals. Te main diferences between dcMS and HPPMS are the discharge behaviour and the plasma composition during the coating process. In conventional dcMS, an increase in plasma and power density is limited due to the thermal load on the target [12]. In contrast, the pulsed power supply enables high-density plasma in front of the sputtering source with peak discharge currents in the order of a few A/cm 2 and a peak power density of several kW/cm 2 . Te pulsed DC voltage with very low duty cycles < 10% provides additional process parameters for tailoring coating growth and coating properties and to optimize the performance of compound flms [13]. Te result- ing high-power density at the target leads to high electron densities in the magnetron confnement (“magnetic trap”) increasing the probability of ionization between sputtered Hindawi Advances in Materials Science and Engineering Volume 2017, Article ID 4850908, 18 pages https://doi.org/10.1155/2017/4850908