Pt改性Ni_(3)Al基合金短时高温氧化行为研究

Short-Term High Temperature Oxidation Behavior of Pt-Modified Ni_(3)Al-Based Alloys

用冷坩埚悬浮熔炼制备了Ni-xPt-25Al(x=0,10,20,30,at%)系列合金,利用X射线衍射仪、同步热分析仪、扫描电镜和光电子能谱仪(XPS)分析了Pt的添加对晶体结构的影响,研究了Ni-xPt-25Al合金的氧化动力学曲线、氧化物形貌以及抗氧化性能。结果表明:随着Pt含量的升高,Pt改性Ni_(3)Al基合金仍保持γ′相。升温过程和短时等温阶段合金的氧化动力学特征分别符合线性和抛物线氧化物生长动力学规律。Pt有利于氧化物的快速形成,且随Pt含量的增加,氧化膜的完整性和致密性均有所改善。

The Ni-xPt-25 Al(x=0, 10, 20, 30, at%) alloys were fabricated by cold crucible levitation melting under argon atmosphere on a water-cooled Cu crucible. The effects of Pt content on crystal structures, oxidation kinetics, morphologies of oxides, and oxidation resistance of the Ni-xPt-25 Al alloys were studied using X-ray diffraction, simultaneous thermal analyzer, scanning electron microscopy, and X-ray photoelectron spectroscopy(XPS). The results show that Pt-modified Ni_(3)Al-based alloys still keep γ′ phases with increasing Pt content. In heating up and isothermal periods, the oxidation kinetics of the Ni-xPt-25 Al(x=0, 10, 20, 30, at%) alloys yield to the linear and parabolic kinetic laws, respectively. Pt plays a beneficial role in promoting the formation of oxides, meanwhile, the increased addition of Pt also improves the integrality and compactness of the oxide films.