Study on water vapor corrosion resistance of rare earth monosilicates RE2SiO5 (RE = Lu, Yb, Tm, Er, Ho, Dy, Y, and Sc) from first-principles calculations

Abstract

Corrosion resistance of rare earth monosilicates (RE₂SiO₅, RE = Lu, Yb, Tm, Er, Ho, Dy, Y, and Sc) in water vapor has been studied using the first-principles calculations. The results show that the water vapor corrosion resistance of RE₂SiO₅ demonstrates the following order: Sc₂SiO₅ > Dy₂SiO₅ > Y₂SiO₅ > Ho₂SiO₅ > Er₂SiO₅ > Yb₂SiO₅ > Tm₂SiO₅ > Lu₂SiO₅. To further improve their water vapor resistance, a doping strategy has been employed for the first time. Two scenarios have been investigated: one is a half mole proportion of substitution of various rare earth elements for Yb in the Yb₂SiO₅ lattice; the other is a half mole fraction substitution of rare earth elements in RE₂SiO₅ (RE = Lu, Yb, Er and Y) by scandium. It is unveiled that the water vapor resistance of YbScSiO₅ and YScSiO₅ has been greatly improved in contrast to other rare earth monosilicates. The current study provides guidelines for the selection of environmental barrier coatings with a better water vapor corrosion resistance.