奥氏体不锈钢AL-6XN在超临界水中的腐蚀

Corrosion Behavior of Austenitic AL-6XN Stainless Steel in Supercritical Water

研究了奥氏体不锈钢AL-6XN在550℃,600℃和650℃超临界水中的腐蚀行为。采用扫描电镜、X射线能谱仪和X射线衍射仪观察氧化膜的腐蚀形貌、组织结构及元素成分分布。结果表明,AL-6XN不锈钢在超临界水中氧化膜的生长服从固态生长机制,600℃时的腐蚀增重量约为550℃时的3倍,而650℃时其腐蚀增重出现了大幅下降。试样表层形成了富Fe的磁晶石结构腐蚀产物颗粒,其氧化膜呈现双层结构,外层为Fe3O4结构,内层为FeCr2O4和（Ni,Fe）Fe2O4混合尖晶石结构。

The corrosion behavior of AL-6XN stainless steel in supercritical water at 550 ℃,600 ℃ and 650 ℃ was investigated.Morphology,structure and elemental distribution of the oxide film were investigated by SEM,EDS and XRD.The results show that the oxide growth of AL-6XN stainless steel in supercritical water is believed to follow the solid-state growth mechanism,and the weight gained at 600 ℃ were approximately three times of that at 550 ℃,while the weight gained at 650 ℃ reduced drastically.Granular corrosion products with Fe-rich magnetite structure were observed on the surface,and the oxide scale exhibited a dual-layer structure and mainly consisted of an outer Fe3O4 structure and an inner FeCr2O4/（Ni,Fe）Fe2O4 mixed spinel structure.