Properties of chromium thin films deposited in a hollow cathode magnetron powered by pulsed DC or HiPIMS

Pure chromium coatings have been deposited within a hollow cathode powered by means of a pulsed DC or a High Power Impulse Magnetron Sputtering (HiPIMS) supply. The discharge characterization by Optical Emission Spectroscopy (OES) has permitted to highlight that more Cr+ are obtained with the HiPIMS mode. A deposition rate of 28 μm/h has been reached in pulsed DC mode and, in this case, the films present a columnar morphology whereas, in HiPIMS mode, a maximum deposition rate of 3 μm/h is obtained and the films have a compact morphology. X-ray diffraction (XRD) has shown a transition between {211} to random texture with pulsed DC mode when discharge current increases and a {110} texture for coatings deposited in the HiPIMS mode. The hardness is higher for the films deposited in the HiPIMS mode than for those obtained in the pulsed DC mode (1200 HV0.025 and 400 HV0.025 respectively). Oxidation resistance investigations show a barrier effect for all coatings.