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为了研究稀土元素对高温热腐蚀行为的影响,采用机械合金化及热压法制备Fe-20Cr-2.5Al、Fe-20Cr-2.5Al-0.8Y2O3和Fe-20Cr-2.5Al-3Y2O3合金,并研究其在900℃,涂敷Na2SO4盐膜后的热腐蚀行为。结果表明,Fe-20Cr-2.5Al合金腐蚀增重最大,Fe-20Cr-2.5Al-3Y2O3合金腐蚀增重其次,Fe-20Cr-2.5Al-0.8Y2O3腐蚀增重最少,抗热腐蚀性能最好。Fe-20Cr-2.5Al合金的腐蚀膜主要为Fe2O3,在腐蚀膜与镀镍层界面处存在着少量的Al2O3。Fe-20Cr-2.5Al-0.8Y2O3合金的腐蚀膜主要为Cr2O3,在靠近基体一侧有少量的Al2O3。Fe-20Cr-2.5Al-3Y2O3合金的腐蚀膜分为2层,外层为Fe Cr2O4,内层为较致密的Cr2O3。三种合金均未发生内硫化现象。添加Y2O3的Fe-Cr-Al合金的抗热腐蚀性能明显好于对应未添加的合金,其中Fe-20Cr-2.5Al-0.8Y2O3合金好于Fe-20Cr-2.5Al-3Y2O3合金。
In order to study the effect of rare earth elements on hot corrosion behavior at high temperature, Fe-20Cr-2.5Al, Fe-20Cr-2.5Al-0.8Y2O3 and Fe-20Cr-2.5Al-3Y2O3 alloys were prepared by mechanical alloying Its corrosion behavior at 900 ℃ after coating Na2SO4 salt film. The results show that the corrosion weight gain of Fe-20Cr-2.5Al alloy is the highest, the corrosion weight gain of Fe-20Cr-2.5Al-3Y2O3 alloy is the second, and Fe-20Cr-2.5Al-0.8Y2O3 has the least corrosion weight gain and hot corrosion resistance. The corrosion film of Fe-20Cr-2.5Al alloy is mainly Fe2O3, and a small amount of Al2O3 is present at the interface between the etching film and the nickel plating layer. The corrosion film of Fe-20Cr-2.5Al-0.8Y2O3 alloy is mainly Cr2O3, with a small amount of Al2O3 near the substrate side. The corrosion film of Fe-20Cr-2.5Al-3Y2O3 alloy is divided into two layers, the outer layer is Fe Cr2O4, the inner layer is more dense Cr2O3. None of the three alloys experienced internal vulcanization. The hot corrosion resistance of the Fe-Cr-Al alloy with Y2O3 is obviously better than that of the un-added alloy. The Fe-20Cr-2.5Al-0.8Y2O3 alloy is better than the Fe-20Cr-2.5Al-3Y2O3 alloy.