Abstract Micro-spatial chemical information over the corrosion metal surface detected with conventional single-tube amperometric or potentiometric microelectrodes is relatively single in SECM. In this paper, we investigate a novel all solid-state dual function Pt-Pt/IrOx ultramicroelectrode (UME) for the electrochemical/chemical visualization of the corrosion process of 316 L stainless steel at open-circuit potential in a 6.0% FeCl3 solution using both amperometric and potentiometric modes of SECM. For the same solution, without further changes, we performed quasi-simultaneous probe-imaging of the localized Fe2+ concentration for dissolved metal-ions at the local anodes, including pH changes due to the consumption of protons at the local cathodes. Local anodic and cathodic active sites were detected repeatedly at the same position in all images, which is consistent with SEM results, evidenced the formation of stable pit over the 316 L-SS surface. In addition, line scans extracted from the current and pH scan images distinctly display the apparent distance between local anodic current- and cathodic pH- peak sites is approximate 84 μm, with a height of 15 μm height during 12 h immersion. This sensor is of pivotal importance in future studies of micro-spatial chemical environment at solid-liquid interface.

中文翻译：

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316 L 不锈钢表面局部 Fe2+ 和 pH 分布的准同时电化学/化学成像

摘要 用传统的单管电流或电位微电极检测腐蚀金属表面的微空间化学信息在 SECM 中相对单一。在本文中，我们研究了一种新型全固态双功能 Pt-Pt/IrOx 超微电极 (UME)，用于电化学/化学可视化 316 L 不锈钢在 6.0% FeCl3 溶液中在 6.0% FeCl3 溶液中的腐蚀过程。 SECM 的电流和电位模式。对于相同的溶液，在没有进一步改变的情况下，我们对局部阳极溶解金属离子的局部 Fe2+ 浓度进行了准同时探针成像，包括由于局部阴极消耗质子而导致的 pH 值变化。在所有图像的同一位置重复检测到局部阳极和阴极活性位点，这与 SEM 结果一致，证明在 316 L-SS 表面上形成了稳定的凹坑。此外，从电流和 pH 扫描图像中提取的线扫描清楚地显示局部阳极电流和阴极 pH 峰值位置之间的表观距离约为 84 μm，在 12 小时浸渍期间高度为 15 μm。该传感器在未来固液界面微空间化学环境的研究中具有举足轻重的意义。