Ni-Cr-Al-Fe基铸态合金的高温氧化行为

采用熔铸法制备不同Al含量的Ni-Cr-Al-Fe基合金,研究Al含量和预氧化处理对合金在600℃大气中抗氧化性能的影响,并利用FE-SEM(EDS)、XRD对不同状态合金氧化膜的形貌及成分进行对比分析.结果表明:Ni-Cr-Al-Fe基合金在600℃时的氧化动力学曲线较好地遵循抛物线规律,铝含量的增加以及预氧化处理均...

High-temperature oxidation behavior of as-cast Ni-Cr-Al-Fe based alloys

Ni-Cr-Al-Fe based alloys with different Al content were prepared by fusion casting.The effects of Al content and pre-oxidation treatment on oxidation behavior of the Ni-Cr-Al-Fe based alloy were investigated.The morphology and chemical composition of the oxide films were characterized by FE-SEM(EDS) and XRD,respectively.The results show that the oxidized kinetic curves of the Ni-Cr-Al-Fe based alloys at 600 ℃ follow the parabolic rule.Both of the increase of Al content and pre-oxidation treatment can enhance the oxidation resistance of the alloy.The compositions of the oxide films after pre-oxidation at 1 000 ℃ and oxidation at 600 ℃ are closely related to the Al content.Higher Al content is helpful to the formation of single Al2O3 structure,which is beneficial to the oxidation resistance of the alloy.With further oxidation,complex oxide or spinel-type oxide may be formed at the local region of the surface.The oxidation of the matrix of the Ni-Cr-Al-Fe based alloy can be effectively prevented after the pre-oxidation treatment.Stable oxide phase diagram of ternary Ni-Cr-Al alloys at 600 ℃ is also calculated by Wagner’s critical theoretics.