Fundamental Studies of Localized Corrosion Site Chemistry inStainless Steel

本研究为理解局部腐蚀过程中溶液化学的变化提供了新的途径。离子色谱法用于探测闭塞细胞内溶液化学的进展。离子色谱法能够在低至10微升的溶液体积中检测纳克数量的各种离子。该技术允许分析局部腐蚀部位（如裂缝）的溶液化学变化。可以获得控制腐蚀坑形成和扩展的基本过程的新见解。表面分析技术（俄歇光谱和x射线光电子能谱）用于检查腐蚀开始前后形成的钝化膜和表面腐蚀层的组成。金属和合金在水环境中的局部腐蚀是一种特别具有破坏性的环境侵蚀形式。人们普遍认为，局部腐蚀部位的开始和扩展的原因是在包含攻击区域的闭塞细胞中形成了高度侵蚀的环境。从本研究中描述的方法中获得的理解可能对减轻点蚀和缝隙腐蚀的策略的发展产生重大影响。

This research takes a new approach to understanding the changes occurring in solution chemistry during localized corrosion. Ion chromatography is employed to probe the progression of solution chemistry within occluded cells. Ion chromatography is capable of detecting nanogram quantities of a wide variety of ions in solution volumes as low as 10 microliters. This technique permits the analysis of changes in solution chemistry at localized corrosion sites such as in crevices. New insights can be obtained into the fundamental processes that control corrosion pit formation and propagation. Surface analysis techniques (Auger spectroscopy and X-ray photoelectron spectroscopy) are used to examine the composition of passive films and surface corrosion layers that form before and after the onset of corrosion. %%% Localized corrosion of metals and alloys in aqueous environments is an especially damaging form of environmental attack. It has generally been accepted that the cause of the initiation and propagation of a localized corrosion site is the formation of a highly aggressive environment in an occluded cell that comprises the area of attack. Understanding obtained from the approach described in this study could have a significant impact on the development of strategies for mitigating pitting and crevice corrosion.