“…Electrochemical impedance spectroscopy (EIS) has been largely used to characterise conversion coated Al alloys. [2][3][4][5]12,15,21,23,24,26 However, only few works have used EIS to characterise Al alloys coated with CeCL, 21,23,24 moreover in all of these works the use of EIS was mainly aimed to extract impedance values upon immersion of the converted samples in the electrolytic solutions. Mansfeld and co-workers [17][18][19] have also used EIS to investigate the corrosion behaviour of Al alloys covered with Ce conversion coatings, however, it seems that the results obtained by these authors are more linked to the thickening of the Al oxide layer than to the presence of a CeCL itself.…”