Effect of Surface Treatment on the Performance of LDH Conversion Films

Abstract

The preparation of layered double hydroxide (LDH) conversion films on aluminum alloy 2024 substrates is reported. The substrates were subjected to four different surface pre-treatments and the corresponding effect on the obtained films studied by scanning electron microscopy (SEM). The corrosion protection conferred to the underlying substrate was investigated by electrochemical impedance spectroscopy (EIS) and by the scanning vibrating electrode technique (SVET). The results show that the best performances are obtained when a laboratory mixed alkaline/acidic procedure or an industrial pre-treatment are applied before the LDH growth, which contribute for the increase of native oxide aluminum stability. (C) 2013 The Electrochemical Society. All rights reserved.