Microstructure and Thermal Properties of Plasma Sprayed Thermal Barrier Coatings from Nanostructured YSZ

摘要

Nanostructured yttria-stabilized zirconia (YSZ) thermal barrier coatings (TBCs) were produced by atmospheric plasma spraying. The microstructure of the sprayed coating was characterized by transmission electron microscope (TEM) and scanning electron microscope (SEM). The nano-coating had a higher porosity of ～25% than the conventional coating, which is mainly attributed to the large amount of intersplat gaps in the nano-coating. The thermal conductivity for the nano-coating was in the level of 0.8-1.1 W/m·K, about 40% lower than that for the conventional coating, indicating a better thermal insulation performance. The nano-TBC exhibited a thermal cycling lifetime of more than 500 cycles, whereas spallation failure of the conventional TBC occurred within 200 cycles. Accelerated sintering could be one of the reasons for the failure of the nano-TBC.