Investigation of improving the thermophysical properties and corrosion resistance of RE2SiO5/RE2Si2O7 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 a 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 (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 °C. To comprehend the corrosion mechanism of CMAS on these silicates, we introduced a reaction–diffusion model, which involved observing the changes in the interface between the corrosion product layer and the silicate block. This was achieved using electron backscatter diffraction (EBSD). These findings lay a theoretical basis for selecting rare earth elements in RE2SiO5/RE2Si2O7 multiphase silicates based on the radii of different rare earth cations.

Keywords

• environmental barrier coatings (ebcs)
• multiphase silicates
• thermal conductivity
• thermal expansion coefficient (cte)
• calcium–magnesium–alumino–silicate (cmas) corrosion resistance
• reaction–diffusion