%0 journal article
%@ 0169-4332
%A Mohedano, M., Matykina, E., Arrabal, R., Mingo, B., Pardo, A.

%D 2015
%J Applied Surface Science

%P 57-67 
%R doi:10.1016/j.apsusc.2015.03.206
%T PEO of pre-anodized Al–Si alloys: Corrosion properties and influence of sealings
%U https://doi.org/10.1016/j.apsusc.2015.03.206
 
%X Voltage-controlled PEO coatings were developed on A356 aluminum alloys (gravity-cast and rheocast) with a pre-anodized layer. The influence of the alloy manufacturing process and the effect of Si-rich phase on the structure and composition of the oxide layers were evaluated using SEM, EDS and XRD. The pre-anodized oxide layer preserves the microstructure of the substrate due to the presence of secondary phases that have a different behavior relative to the matrix during anodizing. PEO coatings consisted of a mixture of α-Al2O3, γ-Al2O3 and mullite. The corrosion behavior and the effectiveness of different sealing techniques based on salts of nickel, cobalt, cerium and phosphonic acid were also studied. Post-treatments improved the hydrophobic properties of the coatings and showed a beneficial effect, significantly increasing the coating impedance and thereby reducing the susceptibility to corrosion.