Ceramic-based abradable sealing coatings for advanced aeroengines: Materials design, structural strategies, and multifunctional performance

With the advancement of modern aeroengines toward higher thrust-to-weight ratios and increased gas temperatures, the control of rotor–stator clearances has become a critical factor influencing engine performance and efficiency. Abradable seal coatings (ASCs), as an effective means of clearance control, have been widely applied to the inner casings of engines. Under high-temperature service conditions (≥1300 ℃), conventional metal-based ASCs are increasingly exhibiting service performance limitations due to their insufficient thermal stability. In contrast, ceramic-based abradable seal coatings, owing to their excellent high-temperature stability and low thermal conductivity, are considered promising candidates for next-generation high-temperature sealing materials. However, the design of such novel ASCs faces numerous key challenges, including crack propagation, the trade-off between abradability and erosion resistance, and coating failure mechanisms under extremely complex service environments. This review systematically summarizes the recent progress in high-temperature ceramic-based ASCs, with a focus on typical material systems, fabrication techniques, key structural design strategies, and their relationship with performance evolution. Comprehensive analysis reveals significant coupling and trade-offs among abradability, hardness, erosion resistance, thermal shock resistance, and corrosion resistance. Achieving balanced performance requires multiscale structural design and multifunctional synergistic optimization. Finally, this paper summarizes the main challenges currently faced in this field and emphasizes that future research should focus more on understanding the evolution of failure mechanisms under complex service environments and on the design and construction of integrated multifunctional coating architectures.