材料期刊网

研究AM60B镁合金表面复合涂层的应用,该涂层由铈?钒转化膜和混合溶胶?凝胶层组成.扫描电镜和X射线能谱分析显示铈?钒转化膜存在开裂结节结构,该转化膜由氧、铈、钒和镁原子组成.转化膜中的裂纹被致密无缺陷的混合溶胶?凝胶薄膜密封.在Harrison溶液中进行电位极化和电化学阻抗测试,结果表明铈?钒转化膜对镁合金提供了很小的防腐保护,然而复合涂层显著增大了镁合金的抗腐蚀性.通过密封铈?钒转化膜的裂缝,溶胶?凝胶膜对合金防护和阻碍腐蚀起到了很大的作用.极化测试后采用扫描电子显微镜验证了电化学测试结果.

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.