Failure Mechanism Analysis of Thermal Barrier Coatings Under a Service Simulation Environment

In this paper, the ceramic coating of thermal barrier coatings (TBCs) was prepared on the surface of the tube specimens by Electron Beam Physical Vapor Deposition (EB-PVD) process. Subsequently, a service simulation was conducted using a simulation device to analyze the failure behavior of the TBCs. The effects of high-temperature sintering and CaO-MgO-Al₂O₃-SiO₂ (CMAS) corrosion on the microstructural evolution, phase structural changes, and insulation performance of the thermal barrier coatings were investigated. The results indicated that with increasing high-temperature sintering time, the “feather” structures at the boundaries of the columnar grains evolve into the “tentacle” structure that facilitates the fusion of adjacent columnar grains, resulting in increased grain diameter and wider gaps. No transformation from t’-ZrO₂ to the monoclinic phase m-ZrO₂ occurred during the high-temperature sintering process. Over time, CMAS wets the coating surface and infiltrates the interior of the coating, causing corrosion to the Yttria-stabilised zirconia (YSZ) and accelerating sintering. A new phase, ZrSiO₄, was formed after corrosion without inducing the transition.