Depth profile analysis of thin passive films on stainless steel by glow discharge optical emission spectroscopy
Depth profile analysis of thin passive films on stainless steel by glow discharge optical emission spectroscopy
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DOI：
10.1016/j.corsci.2008.11.017
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发表时间：
2009-07
影响因子：
8.3
通讯作者：
M. Uemura;Takatoshi Yamamoto;K. Fushimi;Y. Aoki;K. Shimizu;H. Habazaki
中科院分区：
文献类型：
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作者：
M. Uemura;Takatoshi Yamamoto;K. Fushimi;Y. Aoki;K. Shimizu;H. Habazaki
用辉光放电发射光谱（GDOES）分析了含20mass%铬和6mass%钼的高耐蚀312 L不锈钢在2 moldm-3 HCl溶液中于293 K形成的钝化膜。即使在这种腐蚀性溶液中，不锈钢也不会发生点蚀，显示出较宽的钝化电位区。获得的深度分布清楚地显示了两层结构的空气形成的和钝化膜：外层富铁层和内层高度富集铬。构成合金的钼在钝化膜的内层中缺乏，而在外层中富集，特别是在活性溶解电位下。外层的钼物种可以延缓不锈钢的活性溶解，促进形成高度富集铬的稳定钝化膜。氯离子仅存在于钝化膜的最外部分，不渗透到内部。
Thin passive films formed on highly corrosion-resistant type-312L stainless steel, containing 20mass% chromium and 6mass% molybdenum, in 2moldm−3HCl solution at 293K have been analyzed by glow discharge optical emission spectroscopy (GDOES). The stainless steel does not suffer pitting corrosion even in this aggressive solution, showing a wide passive potential region. The depth profiles obtained clearly show a two-layer structure of the air-formed and passive films: an outer iron-rich layer and an inner layer highly enriched in chromium. Alloy-constituting molybdenum is deficient in the inner layer of the passive films and is enriched in the outer layer, particularly at the active dissolution potential. The molybdenum species in the outer layer may retard the active dissolution of stainless steel, promoting the formation of stable passive films highly enriched in chromium. Chloride ions are present only at the outermost part of the passive films, not penetrating into the interior part.