Barbey-Binggeli Morgan, Tileli Vasiliki
Institute of Materials, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.
J Am Chem Soc. 2025 Sep 24;147(38):34920-34932. doi: 10.1021/jacs.5c11352. Epub 2025 Sep 9.
Localized corrosion in metallic materials is a stochastic phenomenon that causes irreversible structural failure. Its initiation, which occurs at the solid-liquid interface on the nanometer scale, remains difficult to predict and challenging to characterize. Herein, we describe an experimental platform that exploits advances in electrochemical liquid-phase scanning and transmission electron microscopy (LPSEM and LPTEM) to study pitting corrosion of thin-film pure aluminum in a saline environment in real time. Galvanostatic measurements at increasing current levels showed that localized corrosion of Al begins with the appearance of blisters in parallel with nanosized pits. It progresses with the coexistence of round and fractal-like pit morphologies before transitioning to the complete fractal-like dissolution of Al at high currents. Although gas bubble formation appeared to be more pronounced at higher currents, we were able to locally probe that the gas is produced at the corrosion front, which we experimentally confirmed to be molecular hydrogen. Our findings reveal the kinetic mechanism of the early stages of localized anodic corrosion in Al, which may have more general implications for proposing corrosion resistance descriptors.
金属材料中的局部腐蚀是一种导致不可逆结构失效的随机现象。其起始发生在纳米尺度的固液界面，仍然难以预测且表征具有挑战性。在此，我们描述了一个实验平台，该平台利用电化学液相扫描和透射电子显微镜（LPSEM和LPTEM）的进展，实时研究薄膜纯铝在盐水环境中的点蚀。在不断增加电流水平下的恒电流测量表明，铝的局部腐蚀始于水泡的出现，同时伴有纳米尺寸的点蚀。它在圆形和分形坑形态共存的情况下发展，然后在高电流下转变为铝的完全分形溶解。尽管在较高电流下气泡形成似乎更明显，但我们能够局部探测到气体是在腐蚀前沿产生的，我们通过实验证实该气体为分子氢。我们的发现揭示了铝局部阳极腐蚀早期阶段的动力学机制，这可能对提出耐腐蚀性描述符具有更广泛的意义。
