Abstract Iron carbonate (FeCO3) is the most common corrosion product in aqueous CO2 corrosion of mild steel. When it forms, the FeCO3 corrosion product layer may be protective, by serving as a diffusion barrier and by affecting the rate of electrochemical reactions at the surface. In the present study, an Electrochemical Quartz Crystal Microbalance (EQCM) was used to investigate the kinetics of precipitation of FeCO3 from an aqueous CO2 corrosion environment. EQCM is a technique providing very accurate in-situ measurement of surface mass change, enabling also simultaneous electrochemical measurements. Three different substrates were used to conduct the FeCO3 precipitation experiments: a cathodically polarized gold-coated quartz crystal, a freely corroding iron-coated quartz crystal and a cathodically polarized iron-coated quartz crystal, at varied temperatures (50–80 °C). Precipitation rates of FeCO3 obtained by using EQCM were repeatable and consistent across different substrates. The obtained precipitation rates were used to determine the theoretical kinetic constant and the activation energy, which was then compared with those reported in the Sun and Nesic model (2008). Discrepancies between the predicted and experimental values were noticed at lower saturation levels and improvements in the model are proposed.

中文翻译：

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EQCM对FeCO 3 沉淀动力学的研究

摘要 碳酸铁（FeCO3）是低碳钢水CO2腐蚀中最常见的腐蚀产物。当它形成时，FeCO3 腐蚀产物层可以起到保护作用，充当扩散屏障并影响表面的电化学反应速率。在本研究中，电化学石英晶体微量天平 (EQCM) 用于研究 FeCO3 从 CO2 水溶液腐蚀环境中沉淀的动力学。EQCM 是一种提供非常准确的表面质量变化原位测量的技术，还可以同时进行电化学测量。三种不同的基材用于进行 FeCO3 沉淀实验：阴极极化镀金石英晶体、自由腐蚀的镀铁石英晶体和阴极极化镀铁石英晶体，在不同温度 (50–80 °C) 下。通过使用 EQCM 获得的 FeCO3 的沉淀率在不同的底物上是可重复和一致的。获得的沉淀速率用于确定理论动力学常数和活化能，然后将其与 Sun 和 Nesic 模型（2008 年）中报告的那些进行比较。在较低的饱和水平下注意到预测值和实验值之间的差异，并提出了对模型的改进。