Improvement of Corrosion and Tribocorrosion Behavior of Pure Titanium by Subzero Anodic Spark Oxidation.

The present investigation reports corrosion and tribocorrosion behavior of anodic spark oxidation (ASO) coatings formed at 20 and -10 °C. Despite the numerous open pores on the layers formed at 20 °C , the plasma discharged channels were blocked on the surfaces of the subzero ASO coatings. According to polarization curves, the samples treated at -10 °C showed a significant increase in the corrosion resistance ( jcorr of 0.75 nA cm-2 ). Electrochemical impedance spectroscopy experiments illustrated lower capacitance and higher resistance of both inner and porous layers formed at low temperature. Subzero ASO coatings also demonstrated the lowest overall open circuit potential drop in tribocorrosion studies.