The electropolishing of Ti sheets in an ethylene glycol–NaCl electrolyte
solution containing various concentrations of ethanol was
performed at a constant voltage at room temperature. A metallic
Ti surface with a mirror-like finish could be produced by adding
20 vol.% ethanol to the ethylene glycol–NaCl electrolyte solution.
With this concentration of ethanol present, the surface quality
was improved, with an Ra of 2.341 nm obtained for the E20-
treated sample. On the other hand, the addition of excess ethanol
(>20 vol.%) resulted in non-uniform electron exchanges between
Ti4+ and Cl− ions. Therefore, adding 20 vol.% of ethanol to the ethylene
glycol–NaCl electrolyte solution was found to be the optimal
ethanol concentration for electropolishing Ti because it maintained
a sufficient thickness of TiCl4 on the working electrode.