The fabrication of a CeO2 coating via cathode plasma electrolytic deposition for the corrosion resistance of AZ31 magnesium alloy

Abstract

In this study, cerium oxide (CeO2) coatings were fabricated using cathode plasma electrolytic deposition for the corrosion protection of AZ31 magnesium alloy. The effects of glycerol addition to the cerium nitrate electrolyte used in CEPD on the structure and corrosion resistance performance of the coatings were investigated. Scanning electron microscopy and X-ray diffraction analyses of the coatings indicate that a denser CeO2 coating was formed after adding glycerol to the cerium nitrate electrolyte. Electrochemical measurements and salt spray testing exhibit that the denser CeO2 coating had a higher corrosion resistance in comparison with the specimen treated without glycerol in the electrolyte and bare magnesium alloy. In addition, the impedance magnitude of the denser CeO2 coating was more than 1 GΩ cm2 after immersion for 96 h in 1 wt% NaCl solution. The adhesiveness of the CeO2-coated magnesium alloy was evaluated using a cross-cut test, the results of which indicate that the coatings had adhered excellently to the substrates. Therefore, the CeO2 coating is a promising anticorrosive measure for magnesium alloys due to its great corrosion resistance and durability.