Etching Microstructures on Metals

本研究探讨了铝合金表面点蚀的机理。表面杂质浓度通过退火和表面溶解处理的变化来评估对坑密度的影响。表面杂质和缺陷浓度监测通过表面分析技术，包括卢瑟福后向散射光谱，二次离子质谱，和正电子湮灭测量。候选缺陷（例如，空位/杂质团簇，位错，表面粗糙度）作为腐蚀位点的重要性之间的关系被寻求。通过氯离子与氧化铝膜的相互作用，研究了坑形成的早期阶段。正电子测量作为温度的函数进行，以便提供缺陷迁移或键能，以便可以表征缺陷的原子结构。这些测量是在掺有杂质元素的高纯度铝上进行的，以确定各种杂质在腐蚀部位的行为。这项研究将产生实用的信息，有助于控制铝及其合金的腐蚀。%%%＊＊＊

9307308 Hebert This research examines the mechanism of surface pitting in aluminum alloys. Surface impurity concentration is varied by annealing and surface dissolution treatments to asses the effect on pit density. Surface impurity and defect concentrations are monitored through surface analytical techniques, including Rutherford Backscattering Spectroscopy, Secondary Ion Mass Spectroscopy, and positron annihilation measurements. Relationships between the importance of candidate defects (e.g., vacancy/impurity clusters, dislocations, surface roughness) as corrosion sites are sought. Early stages of pit initiation are examined through the interaction of chloride ions with aluminum oxide films. The positron measurements are carried out as a function of temperature in order to provide defect migration or bonding energies so that the atomic structure of the defects can be characterized. These measurements are performed on high purity aluminum doped with impurity elements to determine how various impurities behave as corrosion sites. %%% Practical information should result from this research that will assist in controlling corrosion of aluminum and its alloys. ***