Effect of Sigma Phase Precipitation on the Pitting Corrosion Mechanism of Duplex Stainless Steels
Effect of Sigma Phase Precipitation on the Pitting Corrosion Mechanism of Duplex Stainless Steels
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Sigma相析出对双相不锈钢点蚀机理的影响
DOI：
10.20964/2018.10.38
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发表时间：
2018-10-01
影响因子：
1.5
通讯作者：
Jing Hemin
中科院分区：
文献类型：
--
作者：
Wang Yongqiang;Sun Hao;Jing Hemin
本文发现并讨论了SAF2205、SAF2507和Z3CN20.09M三种双相不锈钢在点蚀过程中σ相引起的新现象。的点蚀电位（E p）的所有三个DSS试样的Cr含量的水平变化较小的显着高于试样的Cr含量的变化较大，虽然它们包含几乎相同的σ沉淀。即使有很多的σ相在试样中的Cr含量的变化较小，他们仍然提出了更高的耐点蚀高Ep值。电化学阻抗谱结果和极化试验后试样的微观结构与动电位阳极极化结果一致。由σ沉淀引起的DSS的点蚀主要归因于σ相和贫Cr区之间的Cr含量的差异水平，而不仅仅是贫Cr区本身。
A new phenomenon of the pitting corrosion of three duplex stainless steels (DSSs), SAF2205, SAF2507 and Z3CN20.09M, induced by sigma phases is found and discussed. The pitting potential (E p ) of all three DSS specimens with smaller variations in the level of Cr content is remarkably higher than that of specimens with larger variations in Cr content, although they contain almost the same sigma precipitates. Even if there is much sigma phase in specimens with smaller variations in Cr content, they still present more resistance to pitting corrosion by high E p values. The EIS results and microstructures of the DSS specimens after polarisation tests are in accordance with the potentiodynamic anodic polarisation results. The pitting of DSS induced by sigma precipitation is mainly ascribed to the level of difference in Cr content between the sigma phase and Cr-depleted zone and not only to the Cr-depleted zone itself.