论文部分内容阅读
本文使用旋转盘一环电极的暂态技术——电位阶跃和线性电位扫描技术,研究纯铁在近中性溶液(pH8.4硼酸钠缓冲溶液)中的阳极行为及阴极过程。发现铁的阳极过程主要是生成表面氧化物,钝化是表面相氧化物形成的结果。在稳态钝化区电位范围,i—V图阳极支出现稳态极化曲线所没有的第二波,第二波的峰电流正比于电位扫描速度的一次方,推导出表面价态变化反应,Fe_(surfacc)~(2+)→Fe_(surface)~(3+)的动力学方程予以解释;且证明钝化膜的成分先是Fe~(2+)和Fe~(3+)离子共存,Fe~(3+)离子的含量随电位而变,在一定电位区中将可能只包含Fe~(3+)离子,在更正的电位,膜中出现高价的铁离子(或铁离子缺陷)。(钝化膜的还原主要包括三个阶段:高价铁离子的还原,表面价态变化,及溶液相中Fe~(2+)离子的阴极还原。文中对目前已提出的铁在近中性溶液中阳极钝化的机理和钝化膜的物理模型也作简要的评介。
In this paper, the transient behavior of a ring electrode in a rotating disk-potential step and linear potential scan technique was used to study the anode behavior and cathodic behavior of pure iron in a nearly neutral solution (pH8.4 sodium borate buffer solution). Found that the anode of iron is mainly the formation of surface oxide, passivation is the formation of the surface phase oxide results. In the steady-state passivation region potential range, the anode of i-V shows the second wave which is not in the steady-state polarization curve. The peak current of the second wave is proportional to the first-order of the potential scanning velocity, , Fe (surfacc) ~ (2+) → Fe (surface) ~ (3 +). The results show that the components of passivation film coexist first with Fe 2+ and Fe 3+ ions , The content of Fe ~ (3+) ions varies with the potential, which may only contain Fe ~ (3+) ions in a certain potential region. At the corrected potential, the iron ions (or iron ions) . (The reduction of passivation film mainly includes three stages: the reduction of high-valent iron ions, the change of surface valence state, and the cathodic reduction of Fe 2+ ions in the solution phase. In the anodic passivation mechanism and the physical model of passivation film is briefly reviewed.