Improving corrosion resistance of Ti-6Al-4V alloy through plasma-assisted PVD deposited nitride coatings

TiN and TiAlN/TiAlCrN were deposited on the alloy Ti-6Al-4V by means of plasma-assisted PVD technique in order to improve its corrosion resistance in a 2 M HCI solution at 25, 60, and 80 degrees C. The corrosion behaviour was investigated using open-circuit potential vs. time measurements, potentiodynamic polarization and electrochemical impedance spectroscopy. The uncoated Ti-6Al-4V alloy demonstrated an active behaviour with an active-passive transition in the HCI solution. The TiN and TiAlN/TiAlCrN coated Ti-6Al-4V alloy presented a passive behaviour. The corrosion resistance of the coated alloy was superior, which was evidenced by lower corrosion current densities and higher impedance values. (C) 2014 Elsevier Ltd. All rights reserved.