Microstructural design and thermal cycling performance of a novel layer-gradient nanostructured Sc2O3–Y2O3 co-stabilized ZrO2 thermal barrier coating

Abstract Both thermal insulation property and thermal cycling life are of significant importance to the high-efficiency operation of thermal barrier coatings (TBCs). The spot spallation of the plasma sprayed nanostructured TBCs decreases the effective thickness and thermal insulation property. In this work, a novel layer-gradient nanostructured Sc2O3–Y2O3 co-stabilized ZrO2 (ScYSZ) coating is proposed and employed to enhance the thermal barrier performance. The average thermal insulation temperature of the novel layer-gradient coating is higher than that of the conventional nanostructured counterpart. The thermal cycling life of the layer-gradient TBCs reaches 641 cycles, approximately 70.5% longer than that of the conventional nano-coatings. This layer-gradient coating is more strain tolerant and exhibits much lower increment in the sintering rate and elastic modulus. The mechanism for the extended thermal cycling life of the layer-gradient coating is systematically discussed. This study is expected to provide a new idea for the structural design of high-performance nanostructured TBCs.