ABSTRACT

The development of severe localised corrosion (SLC) on the 2198-T8 alloy was investigated in solutions of various NaCl concentrations (0.001, 0.005 and 0.01 mol L⁻¹). Immersion tests, optical profilometry, conventional and local electrochemical analyses were performed to evaluate the corrosion behaviour of the alloy. Immersion tests showed that the alloy is susceptible to SLC in all conditions, although the pits sizes were dependent on the solution concentration. The largest anodic areas, corresponding to SLC sites, were observed for the sample immersed in 0.001 mol L⁻¹ NaCl, whereas pits with similar sizes were observed for the samples immersed in solutions with 0.005 and 0.01 mol L⁻¹ of NaCl. Moreover, the maximum depth of attack was observed for the sample immersed in 0.001 mol L⁻¹ NaCl. These results were in agreement with the scanning ion-selective electrode technique (SIET) maps which showed stronger acidification on the sample exposed to 0.001 mol L⁻¹ NaCl solution.

摘要

在各种 NaCl 浓度（0.001、0.005 和 0.01 mol L ^-1）的溶液中研究了 2198-T8 合金上严重局部腐蚀（SLC）的发展。进行浸渍试验、光学轮廓测定、常规和局部电化学分析以评估合金的腐蚀行为。浸渍试验表明，该合金在所有条件下都对 SLC 敏感，尽管凹坑大小取决于溶液浓度。对于浸入 0.001 mol L ^-1 NaCl的样品，观察到对应于 SLC 位点的最大阳极面积，而对于浸入 0.005 和 0.01 mol L ^-1溶液的样品，观察到具有相似尺寸的凹坑氯化钠。此外，对于浸入 0.001 mol L ^-1 NaCl的样品，观察到最大侵蚀深度。这些结果与扫描离子选择性电极技术 (SIET) 图一致，该图显示暴露于 0.001 mol L ^-1 NaCl 溶液的样品具有更强的酸化作用。