The Role of Oxide Films on TiS and Ti4C2S2 Inclusions in the Pitting Corrosion Resistance of Stainless Steels
The Role of Oxide Films on TiS and Ti4C2S2 Inclusions in the Pitting Corrosion Resistance of Stainless Steels
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DOI：
10.1149/2.089306jes
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发表时间：
2013
影响因子：
3.9
通讯作者：
Naoya Shimahashi;I. Muto;Y. Sugawara;N. Hara
中科院分区：
文献类型：
--
作者：
Naoya Shimahashi;I. Muto;Y. Sugawara;N. Hara
微电化学极化，热力学计算，俄歇电子能谱进行，以确定影响不锈钢中硫化物和碳硫化物夹杂物的点蚀起始电阻的主要因素。在NaCl溶液中，不锈钢钝化区和反钝化区的TiS和Ti4 C2 S2夹杂物不发生溶解，也不产生点蚀。由Ti-S-Ti S-H2 O和Ti-S-Ti 4 C2 S2-H2 O体系的电位-pH图计算表明，很可能形成富Ti氧化物的表面膜，这一点得到了表面分析的证实。不锈钢钝化区和反钝化区夹杂物表面的Ti氧化物富集层抑制了TiS和Ti4 C2 S2夹杂物的溶解。而MnS夹杂物在NaCl溶液中溶解，并在夹杂物处产生点蚀。虽然MnS夹杂物表面被锰氧化物覆盖，但锰氧化物的耐腐蚀性不足以防止夹杂物溶解和随后的点蚀。硫化物和碳硫化物夹杂物上的氧化物富集的表面层被示出显着增强在夹杂物处的抗点蚀性。
Microelectrochemical polarization, thermodynamic calculations, and Auger electron spectroscopy were performed to determine the predominant factors affecting the pit initiation resistance at sulfide and carbosulfide inclusions in stainless steels. TiS and Ti 4 C 2 S 2 inclusions did not dissolve in the passive or the trans-passive regions of stainless steels in NaCl solutions, and no pits were initiated at these inclusions in NaCl solutions. The calculations made from the potential-pH diagrams for Ti-S-TiS-H 2 O and Ti-S-Ti 4 C 2 S 2-H 2 O systems indicated a high likelihood that Ti-oxide enriched surface films would form, and this was confirmed by surface analysis. The Ti-oxide enriched layers on the inclusions inhibited the dissolution of the TiS and Ti 4 C 2 S 2 inclusions in the passive and trans-passive regions of stainless steels. In contrast, MnS inclusions dissolved in NaCl solutions, and pits were initiated at the inclusions. While MnS inclusion surfaces were covered by Mn-oxides, the corrosion resistance of Mn-oxides was not sufficient to prevent inclusion dissolution and subsequent pit initiation. The oxide enriched surface layers on the sulfide and carbosulfide inclusions were shown to significant enhance pit initiation resistance at the inclusions.