Exceptional thermal shock resistance of RSZ/YSZ coatings for rocket engines at 1800 °C

To meet the demands for high thrust-to-weight ratios and reusability, rocket engines require thermal barrier coatings (TBCs) capable of withstand 1800 °C for prolonged durations. This study presents a novel quaternary rare earth-stabilized cubic zirconia (RSZ) material and systematically optimizes double-ceramic-layer (DCL) RSZ/yttria-stabilized zirconia (YSZ) coating architectures. The optimized structure—with a total thickness of 350 μm and a YSZ-to-RSZ thickness ratio of 1 : 1—exhibits outstanding thermal shock resistance at 1800 °C, achieving a lifespan of 15 cycles and thereby satisfying the performance benchmark for rocket engines under such extreme conditions. In this optimized configuration, failure proceeds through sintering-induced localized spallation, a comparatively gradual process that contributes to prolonged coating durability. These findings highlight the strong potential of RSZ/YSZ coatings for application in next-generation rocket engines operating at 1800 °C.