热障涂层高温失效机理与增效策略研究进展OA

Thermal barrier coatings(TBCs)have become one of the most important surface protection technologies for high-temperature components in aero-engines and gas turbines because of their excellent thermal insulation capability,their ability to reduce substrate temperature,and their significant contribution to extending component service life under severe thermal environments.In recent years,with the continuous increase in thrust-to-weight ratio and turbine inlet temperature,the service conditions of hot-section components have become increasingly harsh,and the requirements for the thermal stability,corrosion resistance,and long-term durability of TBC systems have been greatly intensified.Under such conditions,conventional yttria-stabilized zirconia(YSZ)-based coatings face severe challenges,including phase instability,sintering-induced densification,thermally grown oxide(TGO)thickening,and environmental attacks caused by CMAS,molten salts,and water-vapor-containing atmospheres.The high-temperature failure mechanisms and efficiency enhancement strategies of TBCs are systematically reviewed,and the recent research progress in failure behavior and durability improvement is discussed. Starting from the classification of main high-temperature failure mechanisms,the degradation processes of TBCs under oxidation,residual stress,and corrosion conditions are summarized,and the interaction characteristics and damage evolution paths of these failure modes are clarified.The Oxidation failures are mainly associated with oxygen ingress through pores and microcracks,the formation and continued growth of the TGO layer,the depletion of Al in the bond coat,and the eventual formation of non-protective oxides,all of which progressively weaken interfacial integrity and promote crack initiation and coating spallation.Stress-related failures include quenching stress generated during deposition,thermal mismatch stress caused by differences in thermal expansion among the ceramic top coat,TGO,and bond coat during thermal cycling,and phase-transformation stress caused by the tetragonal-to-monoclinic transformation of YSZ under high-temperature or corrosive environments.Corrosion failures are primarily induced by the infiltration and chemical attack of molten deposits such as CaO-MgO-Al2O3-SiO2(CMAS),sulfate-vanadate salts,and water-vapor-containing atmospheres,which destabilize the ceramic phase,accelerate microstructural degradation,and intensify interfacial damage. Based on these three categories of failure mechanisms,the coupled degradation behavior of TBCs under realistic service environments is further analyzed.It is pointed out that TBC failures are not controlled by a single factor,but rather by the synergistic action of oxidation,stress accumulation,phase transformation,and environmental corrosion.TGO thickening and interfacial rumpling can amplify local stress concentration;CMAS and molten salts can dissolve stabilizing components and induce brittle reaction products and phase transformation;water vapor can accelerate oxide instability and promote ceramic degradation.These processes interact in a nonlinear manner and form a positive feedback loop involving chemical reaction,structural evolution,crack propagation,and interfacial delamination,ultimately resulting in accelerated coating spallation.Therefore,the study of multiphysics field coupled failure has become a key issue in improving the reliability and service lifetime of next-generation TBC systems. Based on the understanding of failure behaviors,recent advances in efficiency enhancement strategies are reviewed from three aspects,namely material composition design,microstructure optimization,and post-treatment regulation.In terms of material design,the development of novel top-coat ceramics,multi-component solid-solution systems,and reactive doping strategies is introduced,and their roles in improving phase stability,reducing thermal conductivity,suppressing sintering,and enhancing resistance to CMAS and molten salt corrosion are discussed.In terms of microstructure design,lamellar structures prepared by atmospheric plasma spraying(APS),columnar coatings fabricated by electron-beam physical vapor deposition(EB-PVD),and functionally graded architectures are compared,and their advantages in thermal insulation,strain tolerance,crack deflection,and interfacial stress mitigation are clarified.In terms of post-treatment processing,laser remelting and vacuum heat treatment are mainly used to heal as-sprayed defects,seal near-surface pores,regulate TGO growth,and promote the formation of a dense and protective α-Al2O3 layer,thereby improving the overall durability of the coating system. Representative results demonstrate that these enhancement strategies can effectively improve the service life of coatings.Under thermal cycling at 1 200℃,the bi-phase solid-solution coating remains intact after 250 cycles,whereas conventional 8YSZ exhibits delamination after 150 cycles,showing a service time extension trend of no less than 67%.Heat treatment can also significantly alleviate bond-coat degradation;after 400 h of isothermal oxidation,the oxide content decreases by about 80%and the porosity decreases by about 90%.By systematically summarizing the current understanding of failure mechanisms and enhancement pathways,this review aims to provide a theoretical basis and technical reference for the rational design,microstructure engineering,and process optimization of advanced TBC systems,and to support the development of more reliable and longer-lasting thermal protection technologies for high-performance propulsion and power-generation applications.