Electrochemical Polishing of Metallic Titanium in Ionic Liquid

Abstract

We investigated the electrochemical dissolution of titanium in TMHA-Tf2N ionic liquid in order to develop a new polishing method for titanium. No dissolution of titanium was observed during the anodic potential sweep up to +6.0 V vs. I3−⁄I− because of the formation of titanium oxide layer during the potential sweep. But when a certain anodic potential was applied instead of the potential sweep, titanium was successfully dissolved to the extent of detectable weight loss. Moreover, TMHA-Tf2N ionic liquid indicated fluorescence X-ray of titanium and the titanium surface showed a shiny metallic silver appearance after experiment. We found that the immersed potential of titanium in the ionic liquid became gradually more negative by increasing the number of mechanical polishings before electrochemical experiments. Using the titanium with an immersed potential of more negative than −0.95 V, the titanium was dissolved anodically at +1.6 V. The potential is within the electrochemical window of TMHA-Tf2N ionic liquid. We believe this technique represents a promising new surface treatment for titanium.