Influence of surface pretreatment on phosphate conversion coating on AZ91 Mg alloy

Chunyan Zhang, Bin Liu, Baoxing Yu, Xiaopeng Lu*, Yong Wei, Tao Zhang, J. M.C. Mol, Fuhui Wang

*Corresponding author for this work

    Research output: Contribution to journalArticleScientificpeer-review

    21 Citations (Scopus)
    17 Downloads (Pure)

    Abstract

    Surface pretreatment is generally applied before application of protective coatings on Mg alloys, which influences surface microstructure and electrochemical activity of the substrate and has an effect on the coating properties. The effect of various pretreatment processes (sand-blasting, grinding and polishing) on the microstructure and corrosion protection performance of phosphate conversion coating (PCC) on AZ91D Mg alloy was investigated in the present study. Sand-blasting cleaning significantly increases the surface roughness and electrochemical activity of the substrate, leading to formation of a porous PCC with inferior corrosion protection performance. In the case of ground/polished Mg alloy, the uniformity and corrosion resistance of the resultant conversion coating are mainly related to the surface roughness. Relatively low surface roughness of the substrate facilitates formation of a corrosion protective PCC.

    Original languageEnglish
    Pages (from-to)414-425
    JournalSurface and Coatings Technology
    Volume359
    DOIs
    Publication statusPublished - 2019

    Bibliographical note

    Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care

    Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.

    Keywords

    • Corrosion protection
    • Mg alloy
    • Phosphate conversion coating
    • Surface pretreatment

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