Real-Time Monitoring of Aluminum Crevice Corrosion and Its Inhibition by Vanadates with Multiple Beam Interferometry in a Surface Forces Apparatus
Real-Time Monitoring of Aluminum Crevice Corrosion and Its Inhibition by Vanadates with Multiple Beam Interferometry in a Surface Forces Apparatus
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表面力装置中多光束干涉法实时监测铝缝隙腐蚀及其对钒酸盐的抑制作用
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
M. Valtiner
中科院分区：
文献类型：
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作者：
B. Shrestha;Qingyun Hu;Theodoros Baimpos;K. Kristiansen;J. Israelachvili;M. Valtiner
作者：Shrestha， BR；胡,问;Baimpos T;Kristiansen K;Israelachvili约;摘要金属的缝隙腐蚀（CC）一直是结构材料研究的热点问题。然而，要实现腐蚀的实时现场可视化，以及在受限几何结构内的抑制作用，仍然是一个挑战。在这里，我们展示了如何利用表面力仪器中的多光束干涉测量技术，在明确定义的约束几何形状内，以埃斯特分辨率直接实时可视化腐蚀过程。我们使用原子光滑的白云母表面在铝上形成圆形~ 1000 μm2的裂缝。暴露于NaCl溶液后，我们可以在这个受限的几何结构中检测和跟踪铝腐蚀的活性位点。铝的CC随机开始于封闭的裂隙口，其中相对表面之间的距离在20-300 nm之间。我们可以直接跟踪氧化物的溶解/形成、腐蚀速率以及由于钒酸钠抑制剂存在于溶液中的缓蚀作用。在添加2.5 mM NaVO3的5 mM NaCl溶液中，形成致密的氧化层可有效抑制CC，而在氯浓度超过50 mM时，抑制作用迅速破坏。抑制层的破坏是由封闭区域内保护性氧化物的快速溶解引起的。我们的技术可以用于监测CC，裂纹尖端内部的腐蚀，以及评估各种金属中的缓蚀剂效率。
Author(s): Shrestha, BR; Hu, Q; Baimpos, T; Kristiansen, K; Israelachvili, JN; Valtiner, M | Abstract: Crevice corrosion (CC) of metals remains a serious concern for structural materials. Yet a real-time in situ visualization of corrosion, and its inhibition within a confined geometry, remains challenging. Here, we present how multiple-beam interferometry in a Surface Forces Apparatus can be utilized to directly visualize corrosion processes in real-time and with Angstrom resolution within welldefined confinement geometries. We use atomically smooth muscovite mica surfaces to form round-shaped ∼1000 μm2 crevices on aluminum. After exposure to NaCl solutions we can detect and track active sites of aluminum corrosion within this confined geometry. CC of aluminum randomly initiates in the confined crevice mouth, where the distance between apposing surfaces is between 20-300 nm. We can directly track oxide dissolution/formation, and corrosion-rates as well as their retardation due to sodium vanadate inhibitors present in solution. Formation of a compacted oxide layer effectively inhibits CC in 5 mM NaCl solutions with 2.5 mM of added NaVO3, while inhibition rapidly breaks down at chloride concentrations above 50 mM. Breakdown of the inhibition-layers is initiated by rapid dissolution of the protective oxide within the confined zone. Our technique may be adapted for monitoring CC, corrosion inside of crack-tips, and evaluation of inhibitor efficiencies in a variety of metals.
影响因子：
16.6
作者：
Raman, Sangeetha;Utzig, Thomas;Valtiner, Markus
通讯作者：
Valtiner, Markus