Synthesis and thermophysical properties of rare-earth tantalate ZrO₂-Dy₃TaO₇ ceramics

Abstract Thermal Barrier Coatings (TBCs) are of major concern to researchers because of their outstanding properties, such as high-temperature resistance, compressive resistance, hardness, and toughness. Its applications are wide-ranging and critical. Examples include hypersonic vehicles, aero-engines, and service in high-temperature and high-impact extreme environments. This work focuses on the preparation, thermal properties (coefficient of thermal expansion, thermal conductivity), and performance evaluation (thermal shock resistance, thermal shock resistance, and bonding) of ZrO 2 -Dy 3 TaO 7 rare earth tantalate ceramic coating materials. The results show that ZrO 2 -Dy 3 TaO 7 possesses a low thermal conductivity (1.25-1.50 W K −1 m −1 , 900°C), a high thermal expansion coefficient (10.80-11.14×10-6 K −1 , 1200°C), which is about half of the value of the thermal conductivity of 7YSZ (2.8-2.2 W K −1 m −1 ). It is better than that of the 7YSZ (10.04×10 −6 K −1 , 1200°C), which meets the performance requirements of the new thermal barrier coating. In addition, ZrO 2 -Dy 3 TaO 7 can achieve more than 6, 000 thermal fatigue cycles at 1200°C, and the ideal number of thermal shock cycles is 4, 040 cycles at the same temperature. These outstanding test results demonstrate that the ceramic coating can effectively protect the substrate material and provide long-term service in high-temperature copper liquid. This research lays the theoretical foundation for the development of next-generation coating materials, particularly for thermal barrier/environmental barrier integrated coating materials.