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Development of Zirconium-based Conversion Coatings for the Pretreatment of AZ91D Magnesium Alloy Prior to Electrocoating

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Magnesium Technology 2011

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Abstract

This work examines the use of hexafluorozirconic acid based solutions at concentrations from 0.025 M to 0.100 M and pH values of 2.0 to 4.0 for the creation of a zirconia-based conversion coating less than 1 micron thick to protect magnesium alloy AZ91D. Similar coatings have been found to give excellent protection for steel and aluminum alloys, but little research has been conducted on its application to magnesium. Work was performed to gain an understanding of the film formation mechanisms and related kinetics using x-ray photo-electron spectroscopy, scanning electron microscopy, and open circuit potential monitoring techniques. A design of experiments approach was taken to determine the effects of acid concentration, pH, and soak time on the corrosion properties both as-deposited and with an application of electrocoat. It was found that the application of the zirconia-based coating significantly increased corrosion resistance, and allowed for an acceptable e-coat application with excellent adherence.

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Author information

Authors and Affiliations

  1. United States Navy, 1240 Isaac Hull Ave. SE, Washington Navy Yard, DC, 20376, USA

    James Reck

  2. General Motors, GM R&D Center, Warren, MI, 48090, USA

    Yar-Ming Wang & Hong-Hsiang Harry Kuo

Authors
  1. James Reck
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  2. Yar-Ming Wang
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  3. Hong-Hsiang Harry Kuo
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Editor information

Editors and Affiliations

  1. Netherlands Organization for Applied Scientific Research (TNO), Netherlands

    Wim H. Sillekens (Senior Scientist) (Senior Scientist)

  2. Department of Materials Science, Engineering at the University, Virginia, USA

    Sean R. Agnew (Research Chair and Associate Professor) (Research Chair and Associate Professor)

  3. US Magnesium LLC, USA

    Neale R. Neelameggham (Technical Development Scientist) (Technical Development Scientist)

  4. Materials Science Division, US Army Research Office (ARO), USA

    Suveen N. Mathaudhu (Program Manager, Dr. Mathaudhu also concurrently serves as an Adjunct Assistant Professor) (Program Manager, Dr. Mathaudhu also concurrently serves as an Adjunct Assistant Professor)

  5. Department of Materials Science and Engineering, North Carolina State University, USA

    Suveen N. Mathaudhu (Program Manager, Dr. Mathaudhu also concurrently serves as an Adjunct Assistant Professor) (Program Manager, Dr. Mathaudhu also concurrently serves as an Adjunct Assistant Professor)

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© 2011 TMS (The Minerals, Metals & Materials Society)

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Reck, J., Wang, YM., Kuo, HH.H. (2011). Development of Zirconium-based Conversion Coatings for the Pretreatment of AZ91D Magnesium Alloy Prior to Electrocoating. In: Sillekens, W.H., Agnew, S.R., Neelameggham, N.R., Mathaudhu, S.N. (eds) Magnesium Technology 2011. Springer, Cham. https://doi.org/10.1007/978-3-319-48223-1_97

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