炼厂循环水中16MnR腐蚀电化学阻抗谱

Electrochemical Impedance Spectroscopy of Corrosion of 16MnR in Circulating Water of Refinery

在确定循环水系统的主要腐蚀影响因素为Cl-浓度、循环水温度、pH和Ca2+浓度的基础上,采用电化学测试系统对16MnR进行电化学阻抗试验并采用等效电路Rs(CtRP)对阻抗谱进行拟合;采用正交试验设计方案并通过极差分析确定各个因素对16MnR腐蚀影响的大小。结果表明,16MnR在炼厂循环水中的电化学阻抗谱为单容抗弧,控制腐蚀过程的参数为电荷转移电阻RP,随着RP值增大阻抗增大腐蚀速率减小;氯离子浓度和循环水温度对16MnR腐蚀影响最大。

The main influencing factors including chloride ion concentration,water temperature,pH value and calcium ion concentration on corrosion of materials in circulating water system were examined.The electrochemical impedance measurements of 16MnR were conducted with electrochemical test system and then the equivalent circuit Rs(CtRP)was adopted to fit the experimental impedance curves.Orthogonal tests were arranged and the sequence of contributions from each factor to the corrosion of 16MnR was obtained.The results showed that the impedance profile of 16MnR in the circulating water showed a single capacitive resistance arc.The parameters controlling the corrosion process included the resistance of charge transfer RPand the impedance value increased with the increase of RP,indicating slowing down of the corrosion rate of 16MnR.The most important impacts on 16MnR corrosion were chloride ions and temperature.