Mechanical and Thermal Properties of Yb 2 SiO 5 : A Promising Material for T/ EBC s Applications

Yb 2 SiO 5 is a promising material for thermal/environmental barrier coatings (T/ EBC s), and its mechanical and thermal properties, which are essential to the coating design and applications, are investigated in this work. Yb 2 SiO 5 has relatively high fracture toughness, bending and compressive strength, but low Young's modulus. It is also tolerant to damage, which is underpinned by grain delamination and cleavage along {100}, {001}, and {040} planes. The average linear coefficient of thermal expansion ( CTE ) is 6.3 × 10 −6 K −1 (473–1673 K) and the anisotropic CTE s are: α a = (2.98 ± 0.16) × 10 −6 K −1 ,α b = (6.51 ± 0.19) × 10 −6 K −1 , and α c = (9.08 ± 0.16) × 10 −6 K −1 . The thermal conductivities are 2.3 and 1.5 W (m·K) −1 at 300 and 1200 K, respectively. The unique combination of these properties warrants Yb 2 SiO 5 promising for T/ EBC s applications.