Effect of dwell time on water–oxygen corrosion behavior and mechanism of Si-18at%Y eutectic alloy at 1300 ℃

In this study, Si-18at%Y alloys were corroded in water–oxygen atmosphere at 1300 ℃ for 90 h to investigate their corrosion behavior. With the increase in the corrosion time, gravity segregation occurred in the alloy. Moreover, SiO₂ was consumed by steam corrosion, leading to the gradual increase in the surface roughness of alloy with time. The molten alloy inside flowed out from the cracks on the surface; therefore, the weight gain rate of alloys first increased and then decreased over time. Owing to the oxygen concentration gradient, temperature gradient, and aluminum cations in corrosion layers, gradient structures were formed in which different structures of yttrium silicate coexisted.