An ac/dc spark anodization method was used to deposit an oxide film (6+/-3 mu m in thickness) on the Al-Cu alloy AA2219. The oxide films were formed at 10 mA/cm(2) for 30 min in an alkaline silicate solution, showing three main stages of growth. Scanning electron microscopy and electron microprobe analysis revealed that the oxide films are not uniform and consist of three main layers, an inner Al-rich barrier layer (similar to 1 mu m), an intermediate Al-Si mixed oxide layer (similar to 2 +/- 1 mu m), and an outer porous Si-rich layer (similar to 3 +/- 3 mu m). In addition, microscopic analysis showed that the Al2Cu intermetallics present in the alloy have not been excessively oxidized during the anodization process and thus are retained beneath the oxide film, as desired. The coating passivity and corrosion resistance, evaluated using linear sweep voltammetry (LSV) in pH 7 borate buffer solution and electrochemical impedance spectroscopy (EIS) in 0.86 M NaCl solution, respectively, were both significantly improved after spark-anodization. (C) 2011 Elsevier Ltd. All rights reserved.