Corrosion Behavior Analysis of Plasma-assited PVD Coated Ti-6Al-4V alloy in 2 M NaOH Solution

Abstract

The work aims the study of the corrosion behavior of nitride plasma-assisted PVD coated Ti-6Al-4V alloy in 2 M NaOH at 25 and 60°C, using open-circuit potential (OCP) versus time measurements, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The uncoated Ti-6Al-4V alloy showed a passive behavior. The TiN and TiAlN/TiAlCrN coated Ti-6Al-4V alloy also presented a passive behavior and the corrosion potential remained at the same range when compared with the potential of the uncoated alloy. The TiN hard coating showed a superior corrosion resistance, which was evidenced by lower corrosion current densities and higher impedance values. The increase in temperature decreased the corrosion resistance of both uncoated and coated alloy in NaOH.