Enhanced thermophysical properties and CMAS corrosion resistance via multicomponent design: Developing a novel rare earth disilicate

The continual increase in the operating temperature of turbine engines necessitates the development of environmental barrier coatings (EBCs) materials with superior thermophysical properties and enhanced resistance to Cao-MgO-Al 2 O 3 -SiO 2 (CMAS) corrosion. Four environmental barrier coatings candidates Yb 2 Si 2 O 7 , (Yb 0.5 Sc 0.5 ) 2 Si 2 O 7 , (Yb 0.25 Sc 0.25 Tm 0.25 Ho 0.25 ) 2 Si 2 O 7 , and (Yb 0.25 Sc 0.25 Tm 0.25 Gd 0.25 ) 2 Si 2 O 7 were prepared. Subsequently, their thermophysical and CMAS resistance properties were tested. Results show that compared to pure Yb 2 Si 2 O 7 , (Yb 0.25 Sc 0.25 Tm 0.25 Gd 0.25 ) 2 Si 2 O 7 reveals superior high-temperature thermophysical properties, which are attributed to its higher CTE (5.16 ×10 −6 K −1 , 1200 °C) and lower thermal conductivity (1.46 W·m −1 ·K −1 , 1200 ℃). Furthermore, (Yb 0.25 Sc 0.25 Tm 0.25 Gd 0.25 ) 2 Si 2 O 7 exhibits a higher CMAS corrosion resistance than pure Yb 2 Si 2 O 7 due to the reaction layer formed by the accumulation of strip and irregular-like apatite. Therefore, (Yb 0.25 Sc 0.25 Tm 0.25 Gd 0.25 ) 2 Si 2 O 7 material emerges as a promising candidate for EBCs, demonstrating exceptional properties at elevated temperatures.