Study on the Formation of Calcareous Deposits on High Manganese Aluminum Bronze by Polarization Potential
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摘要: 采用恒电位极化和电化学阻抗谱（EIS）技术研究了青岛天然海水中不同极化电位下高锰铝青铜的保护电流密度和表面状态随时间的变化过程，利用扫描电镜（SEM）和能谱X射线（EDX）分析了阴极极化产物的微观形貌和元素组成。结果表明，极化168 h后，-0.8 V和-0.5 V两种极化电位下，高锰铝青铜表面都能够形成明显的钙质沉积层，主要成分都是CaCO3；-0.8 V的极化电位下，高锰铝青铜虽然表面形成了铁锰氧化物，但其稳定保护电流密度更低，钙质沉积层膜电阻和电荷转移电阻值更高，钙质沉积层结构也更加致密。因此，-0.8 V的极化电位比-0.5 V的极化电位对高锰铝青铜具有更高的阴极保护效率。Abstract: Cathodic polarization and electrochemical impedance spectroscopy (EIS) were applied to study the changes of protective current density and surface state of high manganese aluminum bronze at different cathodic polarization potentials in seawater.The micro-morphologies and elemental compositions of cathodic polarization products were analyzed by scanning electron microscopy (SEM) and energy spectrum X-ray analysis (EDX).The results show that the surface of high manganese aluminum bronze is covered by the calcareous deposits at polarization potentials of-0.8 V and-0.5 V after 168 hrs of polarizing, and the main component is Ca CO3.At polarization potential of-0.8 V, iron and manganese oxide is formed on the surface of high manganese aluminum bronze, but the density of the steady protection current is lower, the resistance of the calcareous deposit and the charge transfer resistance are higher, and the structure of the calcareous deposit is more compact.Therefore, the cathodic protection efficiency for high manganese aluminum bronze at the polarization potential of-0.8 V is higher than that at the polarization potential of -0.5 V.
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