Fe-Cr-Mn合金在湿润环境中的氧化行为研究

Fe- Cr-Mn alloys are becoming a promising candidate material for interconnectors of solid oxide fuel cells (SOFC) stacks because of the formation of an conductive scale containing (Mn,Cr)3O4 spinel at intermediate temperature range of 650~800 . To better understand their scaling mechanism and evaluate their high temperature performance for SOFC interconnects, the oxidation of Fe-13Cr-xMn alloys with different Mn content (x=0.5, 1, 2) was investigated both in dry and wet air at 800 . The experimental results indicated that all alloys exhibited excellent oxidation-resistance in dry atmosphere. The Fe-Cr-Mn alloys with Mn less than 1% could easily formthe conductive (Mn, Cr)3O4 spinel, which can effectively hinder the volatilization of chromium from the surface of the alloys. However, the oxide Mn2O3 presented in the scale after the manganese content of the alloy increased up to 2%. These had an impact on the high temperature performance of the alloy. In the wet atmosphere, the instability oxidation of all alloys occurred and a large amount of oxide products formed on the surface of the alloys, in contrast to that in dry atmosphere. The oxidation rates decreased with increasing manganese content, which is mainly attributed to the formation of (Mn, Cr)3O4 spinel with higher Mn content. No accelerated oxidation occurred on Fe-13Cr-2Mn alloy within the first 12 h oxidation. The accelerated oxidation of Fe-Cr-Mn alloy was mainly caused by the reaction between the water vapor and chromia scale. The mechanism of accelerated oxidation and the effect of Mn were reported and elucidated by experimental methods including SEM/EDS and XRD.