LaYbZrO thermal barrier coatings by EB-PVD: Microstructure, thermal shock life and failure behaviors

Abstract

Advanced thermal barrier coatings (TBCs) have attracted extensive attentions due to the good crystal structure stability and low thermal conductivity. The thermal shock life and failure behaviors of advanced TBCs still remain a challenge. This work focuses on crystal structure, thermal expansion coefficients, thermal conductivity, microstructure and failure behaviors of the LaYbZrO/YSZ (LYZ/YSZ) double ceramic layers (DCL) TBCs. The LYZ ceramic material exhibit high thermal expansion coefficients and low thermal conductivity. The LYZ/YSZ DCL TBCs exhibit good thermal shock life at 1100 °C due to the feathery nanostructure with columnar gaps and columnar pores. After thermal shock test, the broken regions occur on the horizontal cracks and vertical cracks area within LYZ, YSZ, TGO, YSZ/TGO interface and LYZ/YSZ interface leading to the TBCs instabilities. The TBCs instabilities play a key role on the failure behaviors of LYZ/YSZ DCL TBCs.