The Effect of Various Additions on the Oxidation Behavior of the γ/γ′ Ni-Based Alloy

Abstract The oxidation behavior of four γ/γ′ Ni-based alloys: without additions, and containing: Hf (1.0 wt%), a combination Y (0.3 wt% 0.03 wt%, respectively), Si 1.0 respectively) was studied in air under isothermal (50 h) thermal cycling (up to 2225 1-h cycles) conditions. Samples were characterized using SEM, EDX XRD techniques. results indicated that all the additions improved resistance alloy but only case materials containing (Hf + Y) long-term effect achieved. Substantial weight losses observed on other unmodified Si)-containing during after short exposure periods, while material Hf, they occurred significantly later. Kinetic studies showed highest rate alloys fastest initial oxidation, prior parabolic law-obeying stage, with Hf-additions, only. indicate superior simultaneous application at levels not exceeding their solubility limits lowering its effectiveness overdoping (1 wt%) cannot be effectively counteracted by addition 1% Si.