Effect of roughness on electrochemical and pitting corrosion of Ti-6Al-4V alloy in 12 wt.% HCl solution at 35 °C

Abstract

This study experimentally investigated the electrochemical corrosion and pitting corrosion of Ti–6Al–4 V alloy samples with different roughness in 12 wt.% HCl solution at 35 °C. The corrosion behavior of these alloy samples was studied by potentiostatic and potentiodynamic polarization. Both the corrosion rate and pitting sensitivity of the sample increased with increasing surface roughness. Moreover, the effect of surface roughness on the corrosion of Ti–6Al–4 V alloy could be characterized by the aspect ratio (w/d) of the peak–valley morphology on the surface, where w and d are the width of the valley and relative depth of the peak. The w/d and true surface areas influenced the pitting corrosion of the alloy. Polishing the surface of the Ti–6Al–4 V alloy can enhance the corrosion resistance of the working surface, rendering the material suitable for use in the oil and gas industries. Keywords: Ti–6Al–4V alloy, Surface roughness, Polarization, Electrochemical impedance spectroscopy, Pitting corrosion