Cyclic Corrosion Behavior of Ni-Based Superalloys in Hot Lithium Molten Salt

Abstract

In this study, the cyclic corrosion behavior of N06230, N07263, and N06625 in a LiCl–Li2O molten salt was investigated at 650 °C in argon atmosphere. The cyclic corrosion behavior was observed through measurements of the oxide morphology and thickness, the extent of internal corrosion, and compositional changes in the oxide scale and the substrate. The corrosion products in the surface corrosion layers of N07263 were (Ni,Co)O, (Ni,Co)Cr2O4, Cr2O3, and TiO2 and those in the surface corrosion layers of N06230 were NiO, NiCr2O4, and Cr2O3, while NiO, NiCr2O4, CrNbO4, and Cr2O3 were identified as the corrosion products of N06625. The internal corrosion behavior of N07263 was localized, while N06230 and N06625 showed uniform corrosion. N07263 exhibited superior corrosion resistance as its corrosion layer was more continuous, dense, and adherent as compared to those of N06230 and N06625.