Alternating current-intermittent contact-scanning electrochemical microscopy (AC-IC-SECM) technique is used for the first time for simultaneous mapping of local electrochemical activity and topography of as-polished, passivated and pickled 304L SS-Zr-4 dissimilar weld joint (explosive welded) surfaces in fresh water at open circuit potential (OCP) without redox mediator. The local surface activity showed good contrast and uniformity, even when the surfaces are in tilted condition and topographic resolution is in good agreement with contact and non-contact profilometry. The difference in current and impedance values on SS and Zr-4 surfaces were ∼100 nA and 200 kΩ, respectively. The images acquired on pickled 304L SS and Zr-4 surfaces after immersion in HNO₃ + HF exhibited a relatively higher current and lower impedance compared to as-polished and passivated surfaces. XPS analysis of Zr-4 pickled surface revealed the presence of ZrOF₂, ZrO₂ and Zr, while pickled 304L SS showed a higher metallic to oxide ratio, indicating less protective thinner passive films, resulting in a relatively higher electrochemical activity. Though 304L SS in passivated condition revealed Cr-oxide enrichment, the higher metallic concentration on 304L SS, resulted in similar electrochemical activity as in as-polished condition. The quantitative XPS analysis corroborated the local electrochemical activity results obtained from AC-SECM technique.

交流间歇接触扫描电化学显微镜 (AC-IC-SECM) 技术首次用于同时绘制抛光、钝化和酸洗 304L SS-Zr-4 异种焊接接头的局部电化学活性和形貌（在没有氧化还原介质的情况下，在开路电位 (OCP) 的淡水中爆炸焊接）表面。局部表面活性显示出良好的对比度和均匀性，即使表面处于倾斜状态并且地形分辨率与接触式和非接触式轮廓测量法非常一致。SS 和 Zr-4 表面上的电流和阻抗值差异分别为~100 nA 和 200 kΩ。浸入 HNO ₃后在酸洗的 304L SS 和 Zr-4 表面上获得的图像 + 与抛光和钝化表面相比，HF 表现出相对较高的电流和较低的阻抗。Zr-4 酸洗表面的 XPS 分析表明存在 ZrOF ₂、ZrO ₂和 Zr，而酸洗 304L SS 显示出更高的金属与氧化物比，表明保护性较薄的钝化膜较少，导致电化学活性相对较高。尽管钝化条件下的 304L SS 显示出 Cr 氧化物富集，但 304L SS 上较高的金属浓度导致与抛光条件下相似的电化学活性。定量 XPS 分析证实了从 AC-SECM 技术获得的局部电化学活性结果。