Research Progress on High-temperature Failure Mechanism and Efficiency Enhancement Strategy of Thermal Barrier Coatings
Thermal barrier coatings (TBCs) are critical for protecting aero-engine and gas-turbine hot-section components, yet conventional yttria-stabilized zirconia (YSZ) coatings degrade severely above 1200 °C through phase destabilization, sintering-induced densification, and environmental attack. This review systematically analyzes high-temperature failure mechanisms governed by coupled oxidation, residual stress, and corrosion. Key degradation modes include thermally grown oxide (TGO) thickening and interfacial rumpling, tetragonal-to-monoclinic phase transformation in YSZ, CMAS and molten-salt infiltration, and water-oxygen synergistic erosion. The dynamic interrelations and nonlinear characteristics of these failure modes are clarified. Efficiency enhancement strategies are categorized into compositional optimization (novel ceramics, multi-component solid solutions, reactive-element doping), microstructural design (lamellar, columnar, and functionally graded architectures), and post-treatment (laser remelting, vacuum heat treatment). Quantitative benchmarks demonstrate that at 1200 °C thermal cycling, BPS coatings remain intact after 250 cycles versus spallation of 8YSZ at 150 cycles, indicating a ≥67% lifetime improvement. Vacuum heat treatment suppresses bond-coat damage, reducing oxide content by ~80% and porosity by ~90% after 400 h isothermal oxidation. These findings provide a theoretical and technical basis for rational design of next-generation high-performance, long-life TBCs.