Microstructure and Corrosion Resistance of Al₂O₃-ZrO₂ Composite Coating on Biomedical Magnesium Alloy Fabricated by Cathodic Plasma Electrolytic Oxidation

Abstract:

A relatively new method called cathodic plasma electrolytic oxidation (CPEO) was development to fabricate Al2O3–ZrO2 composite coating on AZ91 biomedical magnesium alloy. The microstructure and properties of the composite coating including phase composition, surface and cross section morphology, thickness and bonding strength were investigated. The corrosion behavior of the coated magnesium alloy in simulated body fluids(SBF) was primarily evaluated. The results showed that the coating was composed of c-ZrO2, α-Al2O3 and γ-Al2O3. The coating surface was coarse and porous with the average pores diameters of 5 µm. The thickness of the coating was about 60 µm and the bonding strength of coating to the AZ91 substrate was 22 MPa. The polarization test indicated that corrosion potential (Ecorr) and corrosion current density (icorr) of the coated samples in SBF were −1.56V and 8.89×10-7 A/cm2 , respectively, whose corrosion resistance was significantly improved compared to the uncoated sample.

• Periodical: Applied Mechanics and Materials (Volumes 184-185)
• Pages: 1068-1071
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.184-185.1068
• Online since: June 2012
• Authors: Yun Long Wang, Miao Wang, Zhao Hua Jiang
• Keywords: Al₂O₃-ZrO₂ Coating, Biomedical Magnesium Alloy, Cathodic Plasma Electrolytic Oxidation, Corrosion Resistance

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DOI: 10.1016/j.surfcoat.2011.10.060