LAUSR

In recent years, numerous techniques have been developed to mimic nacre-like hierarchical architectures in order to improve the damage tolerance of materials. We present herein a simple strategy to fabricate such a hierarchical architectured Al2O3–Y2O3 composite coating via atmospheric plasma spraying. The evolution of the phase and microstructure of the Al2O3–Y2O3 composite coating were characterized under conditions of high-temperature exposure in air at 800-1350 °C. The hardness and porosity of several typical coatings were determined. In situ formation of dense hierarchical architectured Al2O3–YAG composite coating with improved hardness was achieved after heat treatment at 1350 °C. Compared with Al2O3 coating, elevated toughness was found for the hierarchical architectured Al2O3–YAG composite coating, which can be ascribed to the distribution of YAG phase that contributed to crack termination and deflection, and microbridging. After thermal aging treatment at 1350 °C, the hierarchical architectured Al2O3–YAG composite coating was quite stable after 100 h of thermal exposure. Furthermore, the Al2O3–Y2O3 composite coating exhibited superior sintering resistance compared with the Al2O3 coating.