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采用微弧氧化技术在AZ31B镁合金表面制备陶瓷层,利用其表面多孔结构借助电泳技术沉积有机膜层,对比研究陶瓷层和复合膜层表面粗糙度、表面及截面形貌、电化学性能及划伤腐蚀特性。结果表明:陶瓷层表面放电微孔被电泳层完全填充并形成均匀膜层,复合膜层表面粗糙度明显降低;微弧电泳复合膜层腐蚀电流密度与陶瓷层和基体相比分别降低2个和4个数量级,极化电阻分别增大2个和4个数量级,腐蚀倾向降低;微弧电泳复合膜层电化学阻值与陶瓷层相比增加4个数量级,同时电容值降低4个数量级,耐蚀性显著提高;由于陶瓷层与电泳层的机械嵌合作用,复合膜层划伤腐蚀过程表现为基体腐蚀及陶瓷层与基体界面的破坏,复合膜层界面处结合完好。
The micro-arc oxidation technology was used to prepare the ceramic layer on the surface of AZ31B magnesium alloy. The surface of the ceramic layer was deposited by the electrophoretic technique. The surface roughness, surface and cross-sectional morphology, electrochemical properties and electrochemical properties of the ceramic layer and the composite film were compared. Corrosion characteristics. The results show that the micro-arc discharge on the surface of the ceramic layer is completely filled by the electrophoretic layer and forms a uniform film layer, and the surface roughness of the composite film layer is significantly reduced. The corrosion current density of the micro-arc electrophoresis composite film layer is reduced by 2 4 orders of magnitude, the polarization resistance increased by 2 and 4 orders of magnitude respectively, and the corrosion tendency decreased. The electrochemical resistance of micro-arc electrophoresis composite film increased by 4 orders of magnitude compared with the ceramic layer, while the capacitance decreased by 4 orders of magnitude The corrosion of the composite film is marked as corrosion of the matrix and the destruction of the interface between the ceramic layer and the matrix due to mechanical chimerism between the ceramic layer and the electrophoresis layer. The interface of the composite film layer is intact.