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Inorganic Conversion Coatings: Composition , Mechanism, and Paint Adhesion

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Conversion Coatings for Magnesium and its Alloys

Abstract

From chromate- and phosphate- to zirconium-based, various inorganic conversion coatings for Mg alloys have been investigated in the past decades. The main function of conversion coatings is to improve the corrosion resistance and adhesion of the subsequent paints (organic coatings) on Mg alloys. Although inorganic conversion systems are developed based on different reactants, the deposition mechanisms can be categorized in two major types: reduction-type motivated by hydrogen evolution reaction and oxidation-type by dissolution of Mg. The difference in deposition mechanism is decisive for both chemical composition and defects of conversion coatings and thus strongly affects the corrosion properties of coated Mg alloys. Due to the limited corrosion resistance improvements in conversion coating treatment, a posttreatment of painting is usually required to provide additional protection to Mg alloys. Unlike inorganic conversion coatings formed chemically or electrochemically, most paints are attached on Mg alloys physically, and the adhesion of paints is crucial to ensure the long-term corrosion protection performance. The inorganic conversion coating thus plays an important role in providing barrier protection itself and strengthening the adhesion of subsequent paints on Mg articles.

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Authors and Affiliations

  1. Department of Engineering Science and Ocean Engineering, National Taiwan University, Taipei, Taiwan

    Yu-Ren Chu & Yueh-Lien Lee

  2. Department of Materials Science and Engineering, National Taiwan University, Taipei, Taiwan

    Chao-Sung Lin

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  1. Yu-Ren Chu
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  2. Yueh-Lien Lee
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  3. Chao-Sung Lin
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Correspondence to Chao-Sung Lin .

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Editors and Affiliations

  1. Interdisciplinary Research Center for Advanced Materials, King Fahd University of Petroleum and Minerals (KFUPM), Dhahran, Saudi Arabia

    Viswanathan S. Saji

  2. School of Mechanical, Aerospace and Nuclear Engineering (MANE), Ulsan National Institute of Science and Technology (UNIST), Ulsan, Korea (Republic of)

    T. S. N. Sankara Narayanan

  3. School of Engineering, RMIT University, Melbourne, VIC, Australia

    Xiaobo Chen

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Chu, YR., Lee, YL., Lin, CS. (2022). Inorganic Conversion Coatings: Composition , Mechanism, and Paint Adhesion. In: Saji, V.S., Sankara Narayanan, T.S.N., Chen, X. (eds) Conversion Coatings for Magnesium and its Alloys. Springer, Cham. https://doi.org/10.1007/978-3-030-89976-9_2

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