铝对抗磨耐热钢抗氧化性的影响

Effect of Al on Oxidation Resistance of Heat-Abrasion Resistant Steel

研究了不同铝含量的Fe-25Cr-20Ni在900℃、1 000℃和1 100℃的高温氧化行为。其中,Fe-25Cr-20Ni-4.72Al在900℃、1 000℃和1 100℃时的平均氧化速度比Fe-25Cr-20Ni分别降低47.14%、58.14%和17.49%。X射线衍射分析结果表明,氧化膜主要为Fe、Cr的氧化物和尖晶石(NiCr2O4、FeCr2O4),其中在Fe-25Cr-20Ni-4.72Al合金中检测到了Al2O3。对氧化后试样截面进行扫描电镜观察和能谱分析,结果表明,不含铝以及铝的质量分数为1.68%和7.10%的试样氧化后氧化膜分为两层:即厚度较为均匀,存在较多的破碎、剥落的外层和外层与基体之间的较为致密,但存在空穴的内层;铝的质量分数为4.72%的试样氧化膜较为致密,基本无剥落,分层现象不明显,生成的Al2O3存在于氧化膜的最外层,有效防止了材料的进一步氧化。

The oxidation behaviors of heat-abrasion resistant steel Fe-25Cr-20Ni with different content of Al were investigated in air at 900 ℃, 1000℃ and 1 100 ℃ for 150 h. The results show that compared with Fe-25Cr-20Ni, the average oxidation ratse of Fe-25Cr-20Ni-4.72Al at 900 ℃, 1000℃ and 1 100 ℃ decreased by 47.14℃ 58. 14% and 17.49% respectively. Oxide scale of Fe-25Cr-20Ni was composed of the mixture of Feamd Cr oxides and spinelle （NiCr2 04, FeCr2 O4）. While, Al2 O3 was detected in outermost layer of oxide scale of Fe-25Cr-20Ni-4.72Al. Oxide scales of specimens without Al, with 1.68%Al and 7.10%Al consisted of two layers, the outer layer was uniform in thickness, presenting many spallation fragments and the inner layer is compact, with some cavities, while that of specimen with 4.72wt% Al was much compacter, without stratification.