GdYbZrO thermal barrier coatings by EB-PVD: Phase, microstructure, thermal properties and failure

Abstract

Advanced thermal barrier coatings (TBCs) have attracted particular attention due to their low thermal conductivities and high phase stabilities. The thermal properties and failure behaviors of advanced TBCs still remain a challenge in the thermal shock test. This work focuses on thermal expansion coefficient, thermal conductivity, microstructure evolution and failure behaviors of the GdYbZrO/ Y2O3-stabilized ZrO2 (GYZ/YSZ) double ceramic layers (DCL) TBCs. Microstructure characterizations mainly include X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscopy (TEM). The GYZ/YSZ DCL TBCs exhibit good thermal shock lifetime at 1100°C due to the feathery nanostructure with columnar gaps leading to the improvement of strain tolerance. After thermal shock test, the failure regions occur on the cracks area and the interface instability within GYZ, YSZ and TGO. The interface instability has an effect on the failure behaviors of GYZ/YSZ DCL TBCs.