Electropolishing of high-purity aluminium in perchloric acid and ethanol solutions

The electropolishing behaviour of high-purity aluminium with ultrasonic agitation was investigated in ethanol–perchloric acids by using anodic polarization measurement, electrochemical impedance spectroscopy (EIS), scanning electron microscope (SEM), and atomic force microscope (AFM). The results show that the electropolishing behaviour of the aluminium is under mass-transfer control and Al3+ is suggested as the governing species for the salt film mechanism during anodic dissolution in limiting current plateau.