氧化时间及铬含量对Fe-Cr钢高温氧化行为的影响

为了测定不同氧化时间以及铬含量对高温条件下钢材表面氧化铁皮组织和厚度的影响,将Fe-5Cr钢与Fe-10Cr钢在1000℃空气条件下氧化60～180 min,采用增重法绘制其氧化动力学曲线,并利用光学显微镜、能谱仪和X射线衍射仪对氧化铁皮的断面形貌和物相进行研究.结果表明,两试验钢氧化初期为气-固反应,中后期为气...

Effect of oxidation time and chromium content on high temperature oxidation behavior of Fe-Cr steel

In order to determine the effect of different oxidation time and chromium content on microstructure and thickness of the iron oxide scale on steel surface at high temperature, Fe-5Cr steel and Fe-10Cr steel were oxidized at 1000 ℃ under air condition for 60-180 min. The oxidation kinetics curves of this two tested steels were drawn by using mass gain method, and the cross-section morphologies and phases of the steel scales were studied by means of metallographic microscope, energy spectrum and X-ray diffractometer. The results show that the oxidation of two steels is a “gas-solid” reaction in the early stage, and is a “gas phase-iron oxide scale-solid phase” reaction in the middle and late stages. The structure of the oxide scale is composed of outer oxide layer, inner oxide layer and inner oxide zone. When the oxidation time is 180 min, the internal oxide Cr₂O₃ is detected in the Fe-10Cr steel. The oxygen in the air diffuses inward and reacts with chromium in the substrate to produce internal oxide Cr₂O₃, which reacts with FeO in the iron oxide to produce spinel structure product FeCr₂O₄. With the increase of oxidation time, the internal oxide Cr₂O₃ is continuously wrapped by the internal oxide layer and converted to external oxidation. The transformation of internal and external oxidation causes the substrate to be continuously corroded, and the thickness of the iron oxide scale continues to increase.