Investigation of improving the thermophysical properties and corrosion resistance of RE ₂SiO ₅/RE ₂Si ₂O ₇ multiphase silicates by component design with RE doping

Abstract

In this research, a novel method for regulating components in RE2SiO5/RE2Si2O7 multiphase silicates was developed, combining the benefits of suitable thermal expansion coefficient (CTE) and outstanding corrosion resistance against calciummagnesium-alumino-silicate (CMAS). This approach enhanced the overall thermophysical properties. Additionally, the results from the CMAS corrosion resistance test indicated that (Lu1/3Yb1/3Tm1/3)2SiO5/(Lu1/3Yb1/3Tm1/3)2Si2O7 and (Lu1/4Yb1/4Tm1/4Er1/4)2SiO5/(Lu1/4Yb1/4Tm1/4Er1/4)2Si2O7 exhibited exceptional resistance to CMAS penetration, even at temperatures up to 1500 ℃. To comprehend the corrosion mechanism of CMAS on these silicates, we introduced a reactiondiffusion model, which involved observing interface changes between the corrosion product layer and the silicate block. This was achieved using Electron Back Scatter Diffraction (EBSD). These findings lay a theoretical basis for selecting rare earth elements in RE2SiO5/RE2Si2O7 multiphase silicates based on the radius of different rare earth cations.