ISSN: 1003-6326
CN: 43-1239/TG

Vol. 27    No. 2    February 2017

Application of Ce-V/ sol-gel composite coating for corrosion protection of AM60B magnesium alloy
(Physical Chemistry Research Laboratory, Applied Chemistry Department, Faculty of Basic Science, University of Mohaghegh Ardabili, Ardabil 5619911367, Iran)
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.
Key words: magnesium alloy; corrosion; conversion coating; sol-gel
Superintended by The China Association for Science and Technology (CAST)
Sponsored by The Nonferrous Metals Society of China (NFSOC)
Managed by Central South University (CSU)