Magnesium Alloy Effects on Plasma Electrolytic Oxidation Electro-Ceramic and Electro-Coat Formation and Corrosion Resistance
Journal Article
·
· Journal of the Electrochemical Society
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- McMaster Univ., Hamilton, ON (Canada)
- Luxfer Graphic Arts, Madison, IL (United States)
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.
- Research Organization:
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE Office of Energy Efficiency and Renewable Energy (EERE)
- Grant/Contract Number:
- AC05-00OR22725
- OSTI ID:
- 1607067
- Journal Information:
- Journal of the Electrochemical Society, Journal Name: Journal of the Electrochemical Society Journal Issue: 14 Vol. 166; ISSN 0013-4651
- Publisher:
- IOP Publishing - The Electrochemical SocietyCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Similar Records
Advanced characterization study of commercial conversion and electrocoating structures on magnesium alloys AZ31B and ZE10A
Characterization and Properties of Micro-arc Composite Ceramic Coatings on Magnesium Alloys
Journal Article
·
Wed Mar 30 20:00:00 EDT 2016
· Surface and Coatings Technology
·
OSTI ID:1247943
Characterization and Properties of Micro-arc Composite Ceramic Coatings on Magnesium Alloys
Conference
·
Tue May 21 00:00:00 EDT 2013
·
OSTI ID:1239499