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Title: Magnesium Alloy Effects on Plasma Electrolytic Oxidation Electro-Ceramic and Electro-Coat Formation and Corrosion Resistance

Abstract

Plasma electrolytic oxidation (PEO) electro-ceramic (EC) coatings with and without an epoxy-base electro-coat (E-coat) overlayer were studied on four magnesium alloys using the same process deposition parameters: Mg-3Al-1Zn (AZ31B), Mg-9Al-0.5Zn (AZ91D), Mg-1.5Zn-0.3Zr-<0.5Nd (ZE10A, ZEK100 type), and Mg-4Y-(<2.5 Nd)-0.4Zr (WE43). A similar magnesium-fluoride (Mg-F) base EC chemistry formed on all four alloys. However, the morphology of the EC was significantly impacted by the substrate alloys, with higher alloy Al or Zr/rare earth (RE) levels also resulting in thicker coatings. A duplex EC structure formed on AZ31B, AZ91D, and ZE10, with a submicron inner layer and a thicker outer porous layer; whereas a striated multi-layer inner region and thick porous outer region formed on WE43. The EC coated alloys exhibited similar corrosion resistance to the bare alloys due to coating porosity, with the best corrosion resistance exhibited by AZ91D and WE43. After applying the E-coat overlayer, similar, excellent corrosion resistance was exhibited for all four EC + E-coated alloys. Scribing of the EC + E-coat to controllably introduce a coating defect degraded corrosion resistance, particularly for WE43, which suffered from E-coat blistering due to susceptibility of the inner striated EC layer to delamination.

Authors:
ORCiD logo [1]; ORCiD logo [1];  [2]; ORCiD logo [2]; ORCiD logo [1]; ORCiD logo [1];  [3]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  2. McMaster Univ., Hamilton, ON (Canada)
  3. Luxfer Graphic Arts, Madison, IL (United States)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE)
OSTI Identifier:
1607067
Grant/Contract Number:  
AC05-00OR22725
Resource Type:
Accepted Manuscript
Journal Name:
Journal of the Electrochemical Society
Additional Journal Information:
Journal Volume: 166; Journal Issue: 14; Journal ID: ISSN 0013-4651
Publisher:
IOP Publishing - The Electrochemical Society
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE

Citation Formats

Brady, Michael P., Leonard, Donovan N., McNally, Elizabeth A., Kish, Joseph R., Meyer, III, Harry M., Cakmak, Ercan, and Davis, Bruce. Magnesium Alloy Effects on Plasma Electrolytic Oxidation Electro-Ceramic and Electro-Coat Formation and Corrosion Resistance. United States: N. p., 2019. Web. https://doi.org/10.1149/2.0531914jes.
Brady, Michael P., Leonard, Donovan N., McNally, Elizabeth A., Kish, Joseph R., Meyer, III, Harry M., Cakmak, Ercan, & Davis, Bruce. Magnesium Alloy Effects on Plasma Electrolytic Oxidation Electro-Ceramic and Electro-Coat Formation and Corrosion Resistance. United States. https://doi.org/10.1149/2.0531914jes
Brady, Michael P., Leonard, Donovan N., McNally, Elizabeth A., Kish, Joseph R., Meyer, III, Harry M., Cakmak, Ercan, and Davis, Bruce. Tue . "Magnesium Alloy Effects on Plasma Electrolytic Oxidation Electro-Ceramic and Electro-Coat Formation and Corrosion Resistance". United States. https://doi.org/10.1149/2.0531914jes. https://www.osti.gov/servlets/purl/1607067.
@article{osti_1607067,
title = {Magnesium Alloy Effects on Plasma Electrolytic Oxidation Electro-Ceramic and Electro-Coat Formation and Corrosion Resistance},
author = {Brady, Michael P. and Leonard, Donovan N. and McNally, Elizabeth A. and Kish, Joseph R. and Meyer, III, Harry M. and Cakmak, Ercan and Davis, Bruce},
abstractNote = {Plasma electrolytic oxidation (PEO) electro-ceramic (EC) coatings with and without an epoxy-base electro-coat (E-coat) overlayer were studied on four magnesium alloys using the same process deposition parameters: Mg-3Al-1Zn (AZ31B), Mg-9Al-0.5Zn (AZ91D), Mg-1.5Zn-0.3Zr-<0.5Nd (ZE10A, ZEK100 type), and Mg-4Y-(<2.5 Nd)-0.4Zr (WE43). A similar magnesium-fluoride (Mg-F) base EC chemistry formed on all four alloys. However, the morphology of the EC was significantly impacted by the substrate alloys, with higher alloy Al or Zr/rare earth (RE) levels also resulting in thicker coatings. A duplex EC structure formed on AZ31B, AZ91D, and ZE10, with a submicron inner layer and a thicker outer porous layer; whereas a striated multi-layer inner region and thick porous outer region formed on WE43. The EC coated alloys exhibited similar corrosion resistance to the bare alloys due to coating porosity, with the best corrosion resistance exhibited by AZ91D and WE43. After applying the E-coat overlayer, similar, excellent corrosion resistance was exhibited for all four EC + E-coated alloys. Scribing of the EC + E-coat to controllably introduce a coating defect degraded corrosion resistance, particularly for WE43, which suffered from E-coat blistering due to susceptibility of the inner striated EC layer to delamination.},
doi = {10.1149/2.0531914jes},
journal = {Journal of the Electrochemical Society},
number = 14,
volume = 166,
place = {United States},
year = {2019},
month = {10}
}

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Works referenced in this record:

The Influence of Microstructure on the Corrosion of Magnesium Alloy ZEK100
journal, February 2015

  • Asmussen, R. Matthew; Binns, W. Jeffrey; Jakupi, Pellumb
  • CORROSION, Vol. 71, Issue 2
  • DOI: 10.5006/1387

Effect of variations of Al content on microstructure and corrosion resistance of PEO coatings on Mg Al alloys
journal, January 2017


Physical Characterization of Cathodically-Activated Corrosion Filaments on Magnesium Alloy AZ31B
journal, February 2015

  • Cano, Z. P.; Danaie, M.; Kish, J. R.
  • CORROSION, Vol. 71, Issue 2
  • DOI: 10.5006/1384

The corrosion and passivity of sputtered Mg–Ti alloys
journal, March 2016


Aqueous Corrosion Behavior of Micro Arc Oxidation (MAO)-Coated Magnesium Alloys: A Critical Review
journal, April 2014


Rechargeable magnesium battery: Current status and key challenges for the future
journal, October 2014


Corrosion resistance of WE43 and AZ91D magnesium alloys with phosphate PEO coatings
journal, June 2008


The role of anions in the formation and corrosion resistance of the plasma electrolytic oxidation coatings
journal, January 2010


Fundamentals and advances in magnesium alloy corrosion
journal, August 2017


Effects of beta phase on the growth behavior of plasma electrolytic oxidation coating formed on magnesium alloys
journal, May 2019


Insertion/removal kinetics of lithium ion in spinel LiCuxMn2-xO4
journal, December 2007

  • Zeng, Rong-hua; Li, Wei-shan; Dong-sheng, LÜ
  • Transactions of Nonferrous Metals Society of China, Vol. 17, Issue 6
  • DOI: 10.1016/S1003-6326(07)60268-4

Influence of second phase on corrosion performance and formation mechanism of PEO coating on AZ91 Mg alloy
journal, September 2017


The passive behaviour of Mg in alkaline fluoride solutions. Electrochemical and electron microscopical investigations
journal, September 1993


Poisoning the corrosion of magnesium
journal, September 2013


Advanced characterization study of commercial conversion and electrocoating structures on magnesium alloys AZ31B and ZE10A
journal, May 2016


Transmission Electron Microscopy Study of Aqueous Film Formation and Evolution on Magnesium Alloys
journal, January 2014

  • Unocic, K. A.; Elsentriecy, H. H.; Brady, Michael P.
  • Journal of The Electrochemical Society, Vol. 161, Issue 6
  • DOI: 10.1149/2.024406jes

The surface reactivity of a magnesium–aluminium alloy in acidic fluoride solutions studied by electrochemical techniques and XPS
journal, August 2004


Review of Corrosion-Resistant Conversion Coatings for Magnesium and Its Alloys
journal, March 2011

  • Chen, X. B.; Birbilis, N.; Abbott, T. B.
  • CORROSION, Vol. 67, Issue 3
  • DOI: 10.5006/1.3563639

The effect of substrate composition on the electrochemical and mechanical properties of PEO coatings on Mg alloys
journal, January 2010


Magnesium: Current and potential automotive applications
journal, February 2002


Characterization of Oxide Films Formed on Mg-Based WE43 Alloy Using AC/DC Anodization in Silicate Solutions
journal, January 2004

  • Birss, V.; Xia, S.; Yue, R.
  • Journal of The Electrochemical Society, Vol. 151, Issue 1
  • DOI: 10.1149/1.1629095

Growth regularity of ceramic coating on magnesium alloy by plasma electrolytic oxidation
journal, January 2009


Corrosion resistance of oxide layers formed on AZ91 Mg alloy in KMnO4 electrolyte by plasma electrolytic oxidation
journal, September 2009


Metal hydride materials for solid hydrogen storage: A review☆
journal, June 2007


Insights from a Recent Meeting: Current Status and Future Directions in Magnesium Corrosion Research
journal, May 2017

  • Brady, Michael P.; Joost, William J.; David Warren, C.
  • CORROSION, Vol. 73, Issue 5
  • DOI: 10.5006/2255

Characterization of plasma electrolytic oxidation of magnesium alloy AZ31 in alkaline solution containing fluoride
journal, July 2015


Comparative Corrosion Assessment of Coated Alloys for Multi-Material Lightweight Vehicle Architectures
conference, April 2015

  • Kish, Joseph R.; Cano, Zach; Kobylecky, Alexandra
  • SAE 2015 World Congress & Exhibition, SAE Technical Paper Series
  • DOI: 10.4271/2015-01-0738

Preparation of chemical conversion super-black films on ZK61M magnesium alloy
journal, October 2017


Corrosion mechanism and evaluation of anodized magnesium alloys
journal, August 2014


Correlation between KOH concentration and surface properties of AZ91 magnesium alloy coated by plasma electrolytic oxidation
journal, December 2010


Corrosion behavior and cytocompatibility of fluoride-incorporated plasma electrolytic oxidation coating on biodegradable AZ31 alloy
journal, October 2016

  • Tian, Peng; Peng, Feng; Wang, Donghui
  • Regenerative Biomaterials, Vol. 4, Issue 1
  • DOI: 10.1093/rb/rbw036

Protective coatings on magnesium and its alloys — a critical review
journal, April 2002


Tailoring the composition of fluoride conversion coatings to achieve better corrosion protection of magnesium for biomedical applications
journal, January 2014

  • Sankara Narayanan, T. S. N.; Park, Il Song; Lee, Min Ho
  • J. Mater. Chem. B, Vol. 2, Issue 21
  • DOI: 10.1039/C3TB21565B

Recent progress in corrosion protection of magnesium alloys by organic coatings
journal, February 2012


Reducing the corrosion rate of magnesium via microalloying additions of group 14 and 15 elements
journal, January 2018


PEO-coating/substrate interface investigation by localised electrochemical impedance spectroscopy
journal, December 2010


An optimization of pretreatment for the phosphate conversion film on WE43 magnesium alloy
journal, November 2017

  • Dong, Kaihui; Song, Yingwei; Shan, Dayong
  • Materials and Corrosion, Vol. 69, Issue 4
  • DOI: 10.1002/maco.201709742

Transport of Species during Plasma Electrolytic Oxidation of WE43-T6 Magnesium Alloy
journal, January 2008

  • Arrabal, R.; Matykina, E.; Skeldon, P.
  • Journal of The Electrochemical Society, Vol. 155, Issue 3
  • DOI: 10.1149/1.2823374

Plasma electrolytic oxidation of magnesium and its alloys: Mechanism, properties and applications
journal, March 2017

  • Barati Darband, Gh.; Aliofkhazraei, M.; Hamghalam, P.
  • Journal of Magnesium and Alloys, Vol. 5, Issue 1
  • DOI: 10.1016/j.jma.2017.02.004

An investigation of ceramic coating growth mechanisms in plasma electrolytic oxidation (PEO) processing
journal, December 2013


Review—Conversion Coatings Based on Zirconium and/or Titanium
journal, January 2018

  • Milošev, I.; Frankel, G. S.
  • Journal of The Electrochemical Society, Vol. 165, Issue 3
  • DOI: 10.1149/2.0371803jes

A high-specific-strength and corrosion-resistant magnesium alloy
journal, October 2015

  • Xu, Wanqiang; Birbilis, Nick; Sha, Gang
  • Nature Materials, Vol. 14, Issue 12
  • DOI: 10.1038/nmat4435

Modelling and Design of Magnesium and High Entropy Alloys Through Combining Statistical and Physical Models
journal, December 2014


Role of β Phase during Microarc Oxidation of Mg Alloy AZ91D and Corrosion Resistance of the Oxidation Coating
journal, December 2013

  • Wang, Yanqiu; Wang, Xiaojun; Zhang, Tao
  • Journal of Materials Science & Technology, Vol. 29, Issue 12
  • DOI: 10.1016/j.jmst.2013.10.014

Review of Recent Developments in the Field of Magnesium Corrosion: Recent Developments in Mg Corrosion
journal, January 2015

  • Atrens, Andrej; Song, Guang-Ling; Liu, Ming
  • Advanced Engineering Materials, Vol. 17, Issue 4
  • DOI: 10.1002/adem.201400434

Electrochemical behavior of plasma electrolytic oxide coatings on rare earth element containing Mg alloys
journal, December 2013


Biomimetic antimicrobial cloak by graphene-oxide agar hydrogel
journal, December 2016

  • Papi, Massimiliano; Palmieri, Valentina; Bugli, Francesca
  • Scientific Reports, Vol. 6, Issue 1
  • DOI: 10.1038/s41598-016-0010-7

Linking the microstructure of a heat-treated WE43 Mg alloy with its corrosion behavior
journal, December 2015


Deposition and evaluation of duplex hydroxyapatite and plasma electrolytic oxidation coatings on magnesium
journal, May 2015


Characterization of AC PEO coatings on magnesium alloys
journal, May 2009


Corrosion resistance of plasma electrolytic oxidation layer of a non-ignitable Mg–Al–Mn–Ca magnesium alloy
journal, March 2016


Wear behaviour of plasma electrolytic oxide coatings on E21 and WE43 Mg alloys
journal, November 2014