Alumina coatings were synthesized on Al–Cu–Mg alloy substrates through the Plasma enhance microarc oxidation (PMAO) route. Different oxidation times namely 1, 3, 5, 10, 20 and 30 minutes were employed and the coated samples were subjected to coating thickness and surface roughness measurements. Phase composition of the surface layers of the coatings was evaluated through X-ray diffraction. In addition, influence of the oxidation time on the kinetics of the coating formation, surface roughness and microhardness were investigated.