尺寸效应对微电极腐蚀行为的影响

EFFECT OF SIZE ON CORROSION BEHAVIOR OF MICRO-ELECTRODES

采用动电位极化、交流阻抗(EIS)和电化学噪声(ECN)等电化学方法研究了304不锈钢微电极的腐蚀行为。实验结果表明:极限扩散电流密度与电极尺寸之间具有非线性关系,随着电极面积的减小,极限扩散电流密度增大,溶液阻抗减小,双电层电容增大,自腐蚀电位负移,腐蚀电流密度增大。电化学噪声谱表明,随着电极面积减小,亚稳态点蚀噪声峰的频度降低,亚稳态点蚀的发生存在一个临界尺寸。

Effect of size on corrosion behavior of 304 stainless steel micro-electrodes was investigated using electrochemical methods（including potentiodynamic polarization curves,electrochemical impedance spectroscopy （EIS）,and electrochemical noise（ECN））.The results of potentiodynamic polarization and EIS indicated there is a non-linear relationship between the limiting diffusion current density and the area of electrode.The limiting diffusion current density,the corrosion current density and the double-layer capacitance increased with decreasing the electrode size.On the other hand,the corrosion potential negatively shifted and the solution resistance decreased with the decrease of electrode size.The results of ECN demonstrated that there is a critical size for metastable pitting,the frequency of metastable pitting reduced obviously with the decrease of electrode size.