稀土Ce对310S奥氏体耐热不锈钢高温氧化行为的影响

采用热重分析法对不同稀土Ce含量的310S奥氏体耐热不锈钢高温氧化行为进行了系统研究,通过氧化增量曲线分析了相同温度下试验钢的氧化增量规律,并采用场发射电子探针(EPMA)表征氧化膜断面结构及元素分布,同时采用X射线衍射仪(XRD)分析氧化膜的物相组成。结果表明:在循环氧化初期,试验钢的高温氧化增量曲线遵循抛物线规律。试验钢的氧化膜由外层(Cr,Mn)₃O₄“尖晶石”型氧化物和内层Cr₂O₃氧化物组成。适量的稀土元素Ce能促进氧化物/基体界面处的应力释放,同时减少并延缓氧化膜与基体界面孔洞的形成,因而提高氧化膜的抗剥落性。

Effect of rare earth Ce on high temperature oxidation behavior of 310S austenitic heat-resistant stainless steel

High-temperature oxidation behavior of 310S austenitic heat-resistant stainless steel with different rare earth Ce contents was systematically studied by means of thermogravimetric analysis. The oxidation mass gain of the tested steel at same temperature was analyzed by the oxidation mass gain curve. The cross-section structure and element distribution of oxidation film were characterized by field emission electron probe (EPMA), and the phase composition of oxidation film was analyzed by means of X-ray diffraction (XRD). The results show that in the early stage of cyclic oxidation, the high temperature oxidation mass gain curve of the tested steel conforms the parabolic law. The oxide film of the tested steel is composed of an outer layer of (Cr,Mn)₃O₄ “spinel” oxide and an inner layer of Cr₂O₃ oxide. An appropriate amount of rare earth element Ce can promote the release of stress at the oxide/substrate interface, while reduce and delay the formation of voids at the oxide film and substrate interface, thereby improving the spalling resistance of the oxide film.