铝基牺牲阳极的溶解过程和负差异效应

用旋转环一盘电极、电子探针和形貌分析等手段研究了铝基牺牲阳极的溶解过程及其负差异效应。结果表明,铝基牺牲阳极的溶解是从第二相组织边界处引发,从而破坏表面膜而活化。阳极溶解过程中的自腐蚀(表现为析氢)是负差异效应的主要原因,它随外加电流而线性增大。铝基牺牲阳极的负差异效应系数为12.8%。

DISSOLUTION MECHANISM AND NEGATIVE DIFFERENCEEFFECT OF ALUMINUM BASED SACRIFICIAL ANODE

The dissolution mechanism and negative difference effect (NDE) of aluminum sacrificial anode have been studied using rotating ring-disk electrode,electron probe techniques and morphological analysis.The results show that dissolution of the anode initiates at boundary of second phase particles and results in damage of surface passive film and activation. NDE observed in anodic dissolution of the anode is mainly attributed to self-dissolution of naked and activated aluminum, which increases Droporticnallv with impressed anodic current. The NDE coefficient of the anode was measured to be 12.8%.