Fe-Al,Fe-Cr合金在SO_2气氛中的高温腐蚀

HIGH TEMPERATURE CORROSION OF Fe-A1 AND Fe-Cr ALLOYS IN SO_2 GASEOUS ENVIRONMENT

研究了 Fe-Al,Fe-Cr 合金在800℃,900℃和950℃SO_2气氛中的高温腐蚀行为。用石英弹簧检测试样腐蚀增重,以测定高温腐蚀动力学。用 SEM,EMP 和 X 射线衍射分析腐蚀产物。本研究中的 Fe-Al,Fe-Cr 合金腐蚀初期同时硫化/氧化,其中硫化物成为金属离子快速扩散的途径。腐蚀产物膜生长到一定厚度后,扩散到表面的合金元素及铁的浓度降低到只有铁的氧化物在腐蚀产物表面生成。同时 SO_2分子通过腐蚀产物向合金内部扩散,造成材料的内硫化/氧化。

High temperature corrosion behavior of Fe-A1 ,Fe-Cr alloys was studied in SO_2 gaseous environment at 800,900 and 950℃.The corrosion kinetics of the alloys was determined by monitoring weight changes of alloy specimens with a quartz spring .The corrosion product was exa- mined by means of SEM,EMP and X-ray diffraction. For Fe-Al and Fe-Cr alloys tested in this study the materials were subjected to simultaneous sulfidation/oxidation at the early stage of corrosion with a rapid diffusion path for metal ions along sulfides formed.At.the later stage the inerease in corrosion product scale thick- nces was sololy due to growth of iron oxides on the scale surface .At the some time,SO_2 molecules transport inward through the corrosion product scale,thus inducing internal sulfidation/oxidation of the ma- terials.