Article ID Journal Published Year Pages File Type
8012055 Transactions of Nonferrous Metals Society of China 2017 11 Pages PDF
Abstract
Application of a composite coating on AM60B magnesium alloy consisting of cerium-vanadium conversion coating and a hybrid sol-gel layer was investigated. Scanning electron microscopy and energy dispersive X-ray spectroscopy analyses revealed a cracked nodular structure for the cerium-vanadium conversion coating which was mainly composed of O, Ce, V, and Mg atoms. All the cracks in the conversion coating were completely sealed by a thin, compact and defect-free hybrid sol-gel film. Potentiodynamic polarization and electrochemical impedance spectroscopy experiments in Harrison's solution showed that the cerium-vanadium conversion coating provides minimal protection against corrosion while the composite coating significantly increases the corrosion resistance of the magnesium alloy. Sol-gel film provides protection against corrosion by sealing cracks in the cerium-vanadium conversion coating and acting as a barrier. Scanning electron microscopy analyses after polarization tests confirmed the results obtained by the electrochemical tests.
Related Topics
Physical Sciences and Engineering Materials Science Metals and Alloys
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