<br>SA508–309L/308L堆焊接头微电化学不均匀性研究,Analytical Chemistry

当前位置： X-MOL 学术 › Anal. Chem. › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

SA508–309L/308L堆焊接头微电化学不均匀性研究
Analytical Chemistry ( IF 6.7 ) Pub Date : 2023-11-30 , DOI: 10.1021/acs.analchem.3c02178
Zhaogui Lai ₁ , Feifei Huang ₁ , Lei Wen ₁ , Zhaoyang Zhao ₁ , Ying Jin ₁

Affiliation

异种金属焊接接头（DMWJ）的腐蚀行为高度依赖于其异质微观结构。然而，直接测量不同热影响区（HAZ）中微结构的电化学特性是一项艰巨的挑战，因为传统的体电化学只能提供平均信号。在此，使用光刻和毛细管技术在 3.5 wt% NaCl 溶液中测量 SA508–309 L /308L DMWJ 的微电化学特性。具体来说，对168个点（Φ12μm）进行了高通量微电化学测试，包括开路电位（OCP）、电化学阻抗谱（EIS）和动电位极化（PDP）。结果显示了五种典型的 EIS 响应和七种 PDP 曲线（不同大小的电流密度）。热力学和动力学指标图（例如从 EIS 得出的极化电阻、腐蚀电位以及从动电位极化曲线中提取的腐蚀电流）表现出良好的一致性。 SA508 HAZ分区在浸泡试验中的均匀腐蚀趋势与其E _{corr_avg}顺序基本一致，亚临界HAZ（C5，-371 mV）<跨临界HAZ（C4，-546 mV）<细晶HAZ2（C3，- 579 mV) < 细粒度 HAZ1 (C2, −593 mV)。夹杂物的随机存在导致DMWJ的微电化学性质高度不均匀，从而导致局部腐蚀优先发生。此外，宏观腐蚀行为受到腐蚀产物的影响，腐蚀产物表现出保护作用，改变了 SA508 HAZ 的局部电化学活性。微电化学特性的结合可以更全面地了解金属的宏观腐蚀行为和异质微观结构之间的电偶效应。

"点击查看英文标题和摘要"

Study on Microelectrochemical Inhomogeneity of an SA508–309L/308L Overlay Welded Joint

The corrosion behavior of the dissimilar metal welded joint (DMWJ) is highly dependent on its heterogeneous microstructures. However, directly measuring the electrochemical properties of microstructures in different heat-affected zones (HAZs) is a formidable challenge, because traditional bulk electrochemistry can only offer an average signal. Herein, the microelectrochemical properties of an SA508–309L/308L DMWJ were measured in 3.5 wt % NaCl solution using lithography and capillary techniques. Specifically, high-throughput microelectrochemical tests, including open circuit potential (OCP), electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization (PDP), were conducted on 168 spots (Φ 12 μm). Results revealed five typical EIS responses and seven varieties of PDP curves (different magnitudes of the current density). The maps of thermodynamic and kinetic metrics, such as polarization resistance derived from EIS, corrosion potentials, and corrosion currents extracted from potentiodynamic polarization curves, demonstrated good consistency. The uniform corrosion tendency of the SA508 HAZ subregions during the immersion tests is basically consistent with its E_{corr_avg} order of subcritical HAZ (C5, −371 mV) < intercritical HAZ (C4, −546 mV) < fine-grained HAZ2 (C3, −579 mV) < fine-grained HAZ1 (C2, −593 mV). The random presence of inclusions leads to highly heterogeneous microelectrochemical properties of the DMWJ, thereby causing localized corrosion to occur preferentially. Moreover, the macroscopic corrosion behavior is affected by the corrosion products, which display a protective effect that modifies the local electrochemical activity of the SA508 HAZ. The combination of microelectrochemical properties allows for a more comprehensive understanding of the macroscopic corrosion behavior of metals and the galvanic effect between the heterogeneous microstructures.

更新日期：2023-11-30

点击分享查看原文

点击收藏

阅读更多本刊新发论文本刊介绍/投稿指南