Effect of heterogeneous phases on thermal-mechanical properties and CMAS corrosion resistance of (Sc0.33 Er0.33 Yb0.34 ) 2 Si2 O7 ceramics

To investigate the effect of heterogeneous phases on the thermal-mechanical properties and calcium-magnesium- aluminum-silicate (CMAS) corrosion resistance of multi-component disilicate ceramics, four different compositions of (Sc 0.33 Er 0.33 Yb 0.34 ) 2 Si 2 O 7 ceramics were prepared using the solid-phase reaction method with different rare-earth to silicon molar ratios in the raw materials. The (Sc 0.33 Er 0.33 Yb 0.34 ) 2 Si 2 O 7 ceramics containing (Sc 0.33 Er 0.33 Yb 0.34 ) 2 SiO 5 heterogeneous phases showed lower thermal conductivity and hardness but higher bulk ceramic densification, stability of grains at high-temperature, thermal expansion coefficients, and Young's modulus. However, the (Sc 0.33 Er 0.33 Yb 0.34 ) 2 Si 2 O 7 ceramics with SiO2 2 heterogeneous phases exhibited lower thermal expansion coefficients, hardness, and Young's modulus but higher densification, stability of grains, and thermal conductivity. Furthermore, the ceramics containing SiO2 2 heterogeneous phases showed better resistance to CMAS corrosion, which isolated CMAS melts effectively from the surface. Compared to Yb2Si2O7, 2 Si 2 O 7 , (Sc 0.33 Er 0.33 Yb 0.34 ) 2 Si 2 O 7 exhibits lower thermal conductivity and superior resistance to CMAS corrosion, making it a promising candidate material for multifunctional thermal insulation and environmental barrier coatings (TEBCs).