Ablation behavior of Mo/MSZ thick alternate multilayer fabricated by combinative processes of plasma spray and hot isostatic pressing

Thermal barrier and anti-ablation coatings play essential roles in protecting jet nozzles, gas turbine engines and other machines from high temperatures. In this work, a novel curved structure of Mo/MSZ alternate multilayer was designed and fabricated by air plasma spraying. Two steps of the hot isostatic pressing were applied to improve the mechanical strength and interlayer bonding. The alternate structure enabled thick MSZ (Magnesium oxide stabilized Zirconia) layers and show an excellent thermal insulation ability under high-temperature ablation (4.3 MW/m2). Due to the curved surface, the thermal and residual stress is larger at the outer layer and edge, leading to cracks at the most out layer during the ablation. Moreover, during the ablation, the surface suffered steps in the order of hot flush damaging, MSZ and Mo melting, mixing, and Mo oxidizing. This work provided design, reinforcing method and ablation behavior analysis of alternate multilayer of TBC, supporting a solution to increase the performance of thermal insulation and anti-ablation.