Investigation of improving the thermophysical properties and corrosion resistance of RE₂SiO₅/RE₂Si₂O₇ multiphase silicates by component design with RE doping

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 calcium-magnesium-alumino-silicate (CMAS). This approach enhanced the overall thermophysical properties. Additionally, the results from the CMAS corrosion resistance test indicated that (Lu_1/3Yb_1/3Tm_1/3)₂SiO₅/(Lu_1/3Yb_1/3Tm_1/3)₂Si₂O₇ and (Lu_1/4Yb_1/4Tm_1/4Er_1/4)₂SiO₅/(Lu_1/4Yb_1/4Tm_1/4Er_1/4)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 reaction-diffusion 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.