Electropolishing behavior of pure titanium in sulfuric acid–ethanol electrolytes with an addition of water

► The Ti could be electropolished in sulfuric acid-ethanol electrolytes. ► A well-electropolished Ti surface obtained in the 3 M H 2SO 4-ethanol electrolyte. ► Adding H 2O in 0.5 and 1 M H 2SO 4-ethanol electrolytes improve Ti electropolishing. The electropolishing behavior of commercially pure Ti was studied in sulfuric acid–ethanol electrolytes with a small amount of H 2O. The experimental results showed that commercially pure Ti could be electropolished well in the 3 M H 2SO 4–ethanol electrolyte, while inadequately electropolished in 0.5 and 1 M H 2SO 4–ethanol electrolytes. However, the brightening effect on the Ti surface could be clearly observed by the addition of a few volume percent of H 2O to the 0.5 and 1 M H 2SO 4–ethanol electrolytes. The effect of a small amount of H 2O in the H 2SO 4–ethanol electrolytes on the electropolishing behavior of pure Ti was discussed.