A study of fracture toughness and thermal property of nanostructured Yb₂SiO₅ environmental barrier coatings

The objective of this study was to examine the characteristics of a nanostructured Yb₂SiO₅ coating and a conventional Yb₂SiO₅ coating, both prepared using atmospheric plasma spraying (APS). The investigation focused on the phase composition, microstructure, thermal properties, and fracture toughness of the two types of Yb₂SiO₅ coatings. The findings revealed that both nanostructured and conventional coatings consisted of Yb₂SiO₅, Yb₂O₃, and amorphous phases. The nanostructured Yb₂SiO₅ coating exhibited lower residual tensile stress compared to the conventional Yb₂SiO₅ coating, resulting in fewer crack defects in the former. The thermal conductivity of the nanostructured Yb₂SiO₅ coating ranged from 0.71 to 1.22 W/(m·K) between 200 and 1200 °C, while the conventional Yb₂SiO₅ coating exhibited a thermal conductivity range of 0.81–1.32 W/(m·K) within the same temperature range. Consequently, the thermal conductivity of the nanostructured Yb₂SiO₅ coating was lower than that of the conventional counterpart. Furthermore, the presence of nanograins significantly enhanced the fracture toughness of the nanostructured Yb₂SiO₅ coating, which was found to be 1.7 times greater than that of the conventional Yb₂SiO₅ coating.