CAJ | 학술논문

用扫描电化学显微镜(SECM)和电化学阻抗谱(EIS)原位表征了溶液pH值对核电蒸汽发生器800合金溶液中的腐蚀行为的影响。实验结果表明：在酸性氯化钠溶液中， SECM探针渐进曲线为正反馈，表明800合金为活化阳极溶解，腐蚀电位下的EIS图呈现完整的单容抗弧特征；而在中性或者碱性溶液中， SECM探针渐进曲线为负反馈，表明800合金为自钝化，不同阳极电位下的EIS图均呈现不完整的容抗弧特征，但随着阳极极化电位的增加， EIS谱容抗弧半径减小，表明钝化膜的耐蚀性下降；SECM二维扫描图像结果显示探针电流增加，表明电极表面活性增加，即钝化膜的溶解速度增加。而在中性或者碱性溶液中的SECM二维图像中均可观察到若干活性点，这可能与晶界或者金属夹杂物等有关。
용소묘전화학현미경(SECM)화전화학조항보(EIS)원위표정료용액pH치대핵전증기발생기800합금용액중적부식행위적영향。실험결과표명：재산성록화납용액중， SECM탐침점진곡선위정반궤，표명800합금위활화양겁용해，부식전위하적EIS도정현완정적단용항호특정；이재중성혹자감성용액중， SECM탐침점진곡선위부반궤，표명800합금위자둔화，불동양겁전위하적EIS도균정현불완정적용항호특정，단수착양겁겁화전위적증가， EIS보용항호반경감소，표명둔화막적내식성하강；SECM이유소묘도상결과현시탐침전류증가，표명전겁표면활성증가，즉둔화막적용해속도증가。이재중성혹자감성용액중적SECM이유도상중균가관찰도약간활성점，저가능여정계혹자금속협잡물등유관。
The effect of pH on the corrosion resistance of Al oy 800, one of the preferred nuclear steam generator tubing materials, was investigated using in-situ scanning electrochemical microscopy (SECM) and electrochemical impedance spectroscopy (EIS). The experimental results show that positive feedback is observed in the probe approach curve (PAC) in acidic chloride solutions, indicating that Al oy 800 is active in acidic solutions;the EIS at the corrosion potential in acidic solutions exhibits an intact capacitance arc. However, negative feedbacks are observed in the PAC in either neutral or basic chloride solutions, showing that Al oy 800 is self-passivated in these two solutions. The EIS plots at different anodic potentials show incomplete capacitance arcs, and the arc radius decreases with increasing potential, indicating that the corrosion resistance of the passive film decreases. The SECM images show that the surface reactivity increases (or the dissolution rate of the passive film increases) as the polarization potential increases from the corrosion potential to the positive direction; this is verified by an increased tip current. Some“active spots”can be seen on the SECM images in neutral or basic chloride solutions, which are possibly related to grain boundaries, triple points, and/or inclusions.