PEO of pre-anodized Al-Si alloys: Corrosion properties and influence of sealings

M. Mohedano, E. Matykina, R. Arrabal, B. Mingo, A. Pardo

    Research output: Contribution to journalArticlepeer-review


    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.

    Original languageEnglish
    Pages (from-to)57-67
    Number of pages11
    JournalApplied Surface Science
    Publication statusPublished - 1 Jan 2015


    • Aluminum
    • Anodizing
    • Corrosion
    • PEO
    • Post-treatment


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