REACTION MODEL FOR IRON DISSOLUTION STUDIED BY ELECTRODE IMPEDANCE .1. EXPERIMENTAL RESULTS AND REACTION MODEL
REACTION MODEL FOR IRON DISSOLUTION STUDIED BY ELECTRODE IMPEDANCE .1. EXPERIMENTAL RESULTS AND REACTION MODEL
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DOI：
10.1149/1.2127401
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发表时间：
1981-01-01
影响因子：
3.9
通讯作者：
TAKENOUTI, H
中科院分区：
文献类型：
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作者：
KEDDAM, M;MATTOS, OR;TAKENOUTI, H
测定了铁在1 M硫酸酸化的1 M硫酸钠溶液中溶解过程的稳态极化曲线和电极阻抗。这些实验在非常宽的pH（0-5）、电流密度（高达0.1A 9 cm-2）和频率（10：-3-105Hz）范围内进行。三个时间常数，除了归因于双电层容量和电荷转移电阻的高频电容性回路之外，在钝化过程开始之前观察到。基于三种溶解路径的反应模型，通过计算机模拟对实验结果进行了定量解释。在低电流密度下，与连续机制相关的溶解路径控制总体速率。在较高的电流密度，自催化路径，意味着一个亚铁中间体，决定了总电流。另一个自催化路径，与单价铁，在电极阻抗和预钝化过程中起着重要的作用，虽然它的贡献是不普遍的电流在任何pH值。Bonhoeffer和同事努力建立铁溶解在酸性介质中的机制，并提出，第一次，反应模型暗示反应中间物种（1-4）。根据Heusler的说法，铁的溶解发生在两个步骤中，由单价铁耦合（模型I）（4）
Steady-state polarization curves and electrode impedances were measured during the dissolution of iron in 1M Na2SO~ solution acidified by the addition of 1M H2SO4. These experiments were performed within very wide pH (0-5), current density (up to 0.1 A 9 cm-2), and frequency (10:-3-105 Hz) ranges. Three time constants, in addition to the high-frequency capacitive loop attributed to the double layer capacity and the charge transfer resistance, were observed before the onset of the passivation process. The experimental results were quantitatively interpreted by computer simulation on the basis of a reaction model including three dissolution paths. At low current densities, the dissolution path, which can be related to the consecutive mechanism, controls the overall rate. At higher current densities, a self-catalytic path, implying a ferrous intermediate, determines the overall current. Another selfcatalytic path, with monovalent iron, plays an important role in the electrode impedance and the prepassivation process although its contribution to the current is not prevalent at any pH.Bonhoeffer and co-workers strove to establish the mechanism of iron dissolution in acidic medium and proposed, for the first time, reaction models implying reaction intermediate species (1-4). According to Heusler, the dissolution of iron takes place in two steps coupled by monovalent iron (model I)(4)