衰减电流极化技术测定金属瞬时腐蚀速度

DECAYING CURRENT RAMP TECHNIQUE FOR MEASURING CORROSION RATE

一、前言暂态技术非常适合于瞬变过程的腐蚀速度测定。宋诗哲讨论了各种暂态方法,Yegnaraman等用指数律衰减电流对电极进行强极化,所得电位响应在Tafel区为一直线,由其斜率和截距求出腐蚀电流密度和Tafel余率。但由于测量是在很短时间内完成的,非法拉第过程将对测量结果产生影响.Lakshminarayanan等研究了用衰减电流极化技术确定极化电阻、腐蚀速度和双层电容的方法。虽然他考虑了双层电容的影响及其随电位的变化。

The effects of nonfaradic processes on the corrosion rate measurement in decaying current ramp technique are taken into account. The faradic and nonfaradic currents can be separated by adequate mathematical analysis and the uncompensated solution resistance can be corrected through calculation. The polarization resistance, double layer capacitance and its change with potential, anodic and cathodic Tafel slops and corrosion current can be estimated from the data of anodic and cathodic polarization caused by decaying currents.