In situ reaction–based synthesis of a novel nanostructured Lu2SiO5-based environmental barrier coating with controllable Lu2O3 content.

Poor fracture toughness and calcium–magnesium–aluminum–silicate (CMAS) corrosion resistance adversely affect environmental barrier coatings (EBCs) during prolonged service. Herein, an in-situ nanostructured Lu 2 O 3 /Lu 2 SiO 5 composite EBC was successfully prepared using nanostructured Lu 2 SiO 5 feedstocks. The morphologies and phase structures of the Lu 2 SiO 5 feedstocks and the corresponding coating were thoroughly characterized. Additionally, the mechanism of the in suit reaction of the Lu 2 O 3 /Lu 2 SiO 5 composite EBC was examined. The results indicate that the nanostructured as-deposited EBC exhibits a bimodal and dual-phase structure. The nanostructured Lu 2 SiO 5 coating comprises melted lamellae and unmelted or partially melted particles. The phase structure of these unmelted or partially melted particles includes Lu 2 O 3 and X2-Lu 2 SiO 5. The Lu 2 O 3 nanoparticles are formed by the decomposition of Lu 2 SiO 5 during spraying, and their content can be controlled to <15 %, which can enhance the fracture toughness and CMAS corrosion resistance of the EBCs to some extent. [ABSTRACT FROM AUTHOR]