Corrosion of magnesium in humid air
Corrosion of magnesium in humid air
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DOI：
10.1016/j.corsci.2003.09.010
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发表时间：
2004-05-01
影响因子：
8.3
通讯作者：
Svensson, JE
中科院分区：
文献类型：
--
作者：
Lindström, R;Johansson, LG;Svensson, JE
通过原子力显微镜（AFM）和扫描电子显微镜（SEM）研究了环境二氧化碳浓度对镁大气腐蚀的影响，揭示了腐蚀产物的发展和生长。 AFM 研究的表面是使用金刚石刀通过超薄切片法制备的，无需使用水或润滑剂即可产生光滑的表面。还使用机械抛光样品研究了溅射沉积镁膜，用于监测整体腐蚀过程。暴露在 22.0 摄氏度的合成环境中进行，精确控制相对湿度 (95%) 和 CO2（0 或 350 ppm）。腐蚀发生在没有 CO2 的情况下，并且与金属基体中的贵金属夹杂物有关。去除腐蚀产物后，可以明显看到较深的凹坑。相比之下，在 CO 存在的情况下，点蚀受到抑制，腐蚀产物的形成相对均匀；此外，贵金属夹杂物对腐蚀分布没有影响。在长期暴露中也观察到 CO2 的抑制作用，表明 CO2 降低了平均腐蚀速率。介绍了一些机制来解释 CO2 的影响以及贵金属夹杂物对腐蚀行为的作用。 (C) 2003 Elsevier Ltd. 保留所有权利。
The influence of ambient concentrations of carbon dioxide on the atmospheric corrosion of magnesium has been studied by atomic force microscopy (AFM) and scanning electron microscopy (SEM), revealing the development and growth of corrosion products. The surfaces investigated by AFM were prepared by ultramicrotomy, using a diamond knife, to generate a smooth finish without using water or lubricant. Sputter-deposited Mg films were also studied with mechanically polished samples used to monitor the overall corrosion process. The exposures were performed at 22.0 degreesC in a synthetic environment with precise control of relative humidity (95%) and CO2 (0 or 350 ppm). Corrosion is localized in the absence of CO2 and is related to noble inclusions in the metal matrix. After corrosion product removal, relatively deep pits are evident. In contrast, pitting is inhibited in the presence of CO, with relatively uniform corrosion product development; further, the noble inclusions have no effect on the distribution of corrosion. The inhibitive effect of CO2 is also observed in the long-term exposures, showing that CO2 reduces the average corrosion rate. Mechanisms are introduced to explain the effects of CO2 and the roles of the noble inclusions on the corrosion behaviour. (C) 2003 Elsevier Ltd. All rights reserved.