Influence of grain size on tellurium corrosion behaviors of GH3535 alloy

Abstract The effects of grain size on the tellurium corrosion behaviors have been investigated systematically in GH3535 alloy. After the exposure to Te vapor, the triple-layer scales, which consist of Ni 3 Te 2 , Cr 3 Te 4 , MnTe, M 6 C carbides and Fe-riched γ phase, occur in both the fine-grained and coarse-grained specimens. The thicker outer layer, the more discrete inner layer, the shallower Te permeation and Cr 3 Te 4 existence along grain boundaries can be observed in the fine-grained specimens. By comparing the Gibbs free energies and calculating the effective diffusion coefficients, the tellurization mechanism and the role of grain size were discussed.