Advances in EB PVD thermal barrier coatings: materials and processing innovations for CMAS resistance in aero engine applications

Electron-beam physical vapor deposition (EB-PVD) thermal barrier coatings protect aero-engine hot-section components while accommodating cyclic strain through their separated columnar architecture. However, the connected gaps and feather-like substructures also provide pathways for molten calcia–magnesia–alumino–silicate (CMAS) deposits derived from ingested environmental particles. Infiltration couples coating dissolution and phase evolution to reduced optical scattering, increased stiffness, and interfacial damage, undermining thermal insulation and cyclic durability. This review synthesizes materials and processing innovations using a transport–reaction–fracture framework that emphasizes the architecture-specific requirements of EB-PVD systems. Deposit chemistry, particle thermal history, wetting, and column-network topology are linked to the timing and location of infiltration, crystallization, and failure. Yttria-rich zirconia, rare-earth zirconates, garnet-forming aluminates, phosphates, reactive oxide overlays, and emerging multicomponent ceramics are assessed alongside laser surface modification, column refinement, and multilayer designs. The synthesis identifies a common design requirement: protection must restrict connected liquid transport before vulnerable regions are reached without producing a brittle cap or weakening internal interfaces. Favorable reaction products and low penetration depths are therefore evaluated against coating consumption, retained thermal resistance, compliance, and cyclic integrity. A proposed multiscale modeling workflow connects thermodynamic and infiltration analyses to fracture and component-level exposure, while distinguishing mechanistic screening from coating-system validation. Priorities include comparable deposit and thermal histories, repeated melting and deposition, and functional measurements beyond post-exposure penetration depth. The resulting design rules favor localized reactive protection, controlled column-gap connectivity, and a compliant underlying coating, providing a basis for translating laboratory mitigation strategies into reproducible and repairable aero-engine coating systems.