DFT‐Based Insight Into Rare‐Earth Aluminum Oxides R ₃ Al ₅ O ₁₂ (R = Ce and Sm) as Promising Thermal Barrier Coating

ABSTRACT The excellent thermal stability and mechanical strength of rare‐earth aluminum oxides have garnered considerable interest as a potential thermal barrier coating (TBC) material. In this article, the structural, electronic, and thermal stability of R 3 Al 5 O 12 (R = Ce and Sm) compounds were investigated using the full‐potential linearized augmented plane wave (FP‐LAPW) approach. The findings indicate that both compounds maintain structural stability under elevated pressure and temperature conditions. Furthermore, the electronic properties reveal that R 3 Al 5 O 12 (R = Ce and Sm) compounds are metallic. The Gibbs2 code was implemented in WIEN2K software to investigate the thermodynamic behavior of R 3 Al 5 O 12 (R = Ce and Sm) compounds under high‐pressure and high‐temperature conditions. The thermodynamic analysis indicates that Ce 3 Al 5 O 12 exhibits higher structural stability under compressive conditions, making it suitable for high‐pressure applications, while Sm 3 Al 5 O 12 has higher entropy and lower Gibbs free energy, making it more suitable for high thermal load environments. The findings suggest that R 3 Al 5 O 12 (R = Ce and Sm) compounds are the most appropriate candidates for the future TBC systems.

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