超临界水中310-ODS钢表面氧化膜形成机制和性能

Formation Mechanism and Properties of Oxide Film on 310-ODS Steel in Supercritical Water

采用腐蚀增重方法研究310-ODS钢在600℃低溶氧的超临界水中的全面腐蚀敏感性,取样周期分别为100、300、600、1 000、1 500h,对试样表面氧化膜进行扫描电镜、能谱仪和X射线衍射仪分析.结果表明:310-ODS钢在浸泡早期(300h)已经在表面形成较为致密的氧化膜,腐蚀速率快速降低;氧化膜为双层结构,内层致密富Cr,外层多孔富Fe,随着浸泡时间的增加,内层变得均匀,外层变化不大.310-ODS钢在600℃超临界水中的氧化过程满足固态生长机制,晶界处的Y2O3改善了材料的耐腐蚀性能.

The general corrosion susceptibility of 310-ODS steel was evaluated in 600℃supercritical deaerated water by weight gain.The sample periods were 100,300,600,1 000,and 1 500 h.The surface oxide film of 310-ODS steel was analyzed by using scanning electron microscope（SEM）,energy disperse spectroscopy（EDS）and X-ray diffractometer（XRD）.The results show that a dense oxide film is formed on the surface of 310-ODS steel during the early days（300h）and the corrosion rate decreases rapidly.The oxide film is a double-layer structure with a dense Cr-enriched inner layer and a porous Fe-enriched outer layer.The inner layer becomes uniform and the outer layer does not change with the immersing time.The oxidation process of 310-ODS steel in 600℃ supercritical deaerated water meets the solid-state growth mechanism and Y2O3 in the grain boundaries improves the corrosion resistance.