Comparison of the Properties of Rare-Earth Zirconate Thermal Barrier Coatings for Hydrogen-Fueled Gas Turbines

Thermal barrier coatings (TBCs) for hydrogen-fueled gas turbines withstand higher combustion temperatures and increased steam concentrations compared to conventional natural-gas systems. These harsh operating conditions significantly accelerate the thermal degradation of widely used YSZ coatings, emphasizing the need for alternative top-coat materials with improved phase stability and reduced thermal conductivity. In this study, rare-earth zirconate ceramics, Gd2Zr2O7 (GdZO), Tm2Zr2O7 (TmZO), and a mixed composition (Gd0.5Tm0.5)2Zr2O7 (Gd/TmZO), are synthesized and investigated as potential next-generation TBC candidates. Each material was comparatively examined with a focus on crystal structure, thermophysical properties, and thermal conductivity. Furthermore, high-temperature steam exposure experiments were performed to simulate hydrogen combustion environments. Microstructural analyses, high-temperature degradation behavior, and phase stability evaluations were carried out to obtain fundamental experimental data. This study provides essential baseline information for the design and development of high-performance TBC materials suitable for the hydrogen-fueled gas turbine systems.