Preparation and sintering behavior of GdYb-YSZ nanostructured thermal barrier coating

Gd and Yb co-doped YSZ (GdYb-YSZ) is one of the potential ultra-high temperature thermal barrier coatings due to its excellent properties. GdYb-YSZ nanostructured coatings were prepared using atmospheric plasma spraying, and the deposition mechanism, thermal conductivity, and sintering behavior of GdYb-YSZ coatings at 1400 °C were systemically investigated. The results showed that the plasma-sprayed GdYb-YSZ coating with a typical layered structure was composed of a single cubic ZrO2 phase. The GdYb-YSZ nanostructured coating was sintered at 1400 °C, and the defects such as micropores and microcracks gradually healed. After sintering for 100 h, the thermal conductivity of the coating was 1.6 W m−1 K−1 at 800 °C, which was about 65% higher than that of the as-deposited coating. The GdYb-YSZ coating did not undergo phase transformation during sintering. The GdYb-YSZ coating possessed excellent phase stability at 1400 °C.