Microstructure and corrosion resistance of ultrasonic micro-arc oxidation biocoatings on magnesium alloy
micro-arc oxidation (MAO), ultrasonic treatment, magnesium alloy, microstructure, corrosion resistance
The ultrasonic micro-arc oxidation (UMAO) was used to fabricate ceramic coatings on magnesium alloy. UMAO coatings were produced at 60 W input ultrasonic. The effects of the ultrasound on the microstructure, phase composition, elemental distribution and corrosion resistance of the coatings were extensively investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy-dispersive X-ray spectrometry (EDX) and electrochemical workstation. The results showed that ultrasound improved the homogeneous distribution of micro-porous structure. The coatings were mainly composed of MgO ceramic and small amount of calcium and phosphorus with porous structure. The Ca/P ratio of the coatings increased when 60 W ultrasonic was used. The corrosion potential in simulated body fluid (SBF) changed from -1.583 V of bare magnesium alloy to -0.353 V of magnesium alloy coated under 60 W ultrasonic. The corrosion resistance of UMAO coatings was better than that of MAO coatings.
Tsinghua University Press
Lijie QU, Muqin LI, Miao LIU et al. Microstructure and corrosion resistance of ultrasonic micro-arc oxidation biocoatings on magnesium alloy. Journal of Advanced Ceramics 2013, 2(3): 227-234.