Abstract This study explores the synthesis and structural characteristics of pristine and doped La 2 Zr 2 O 7 and Gd 2 Zr 2 O 7 with a focus on their sintering behavior. The pristine La 2 Zr 2 O 7 was found to stabilize in defect pyrochlore structure, which evolves toward a more ordered pyrochlore structure upon high-temperature sintering, evidenced by the appearance and sharpening of superlattice reflections with increasing temperature. The (La₀.₈Gd₀.₂)₂Zr₂O₇ sample exhibited a similar behavior; however, the ordering process is sluggish due to the presence of Gd 3 ⁺ ions. In contrast, the Gd 2 Zr 2 O 7 and (La₀.₂Gd₀.₈)₂Zr₂O₇ samples were stabilized in a dual-phase structure with dominant defect fluorite structure with microdomains of pyrochlore as shown through XRD and Raman analysis. All the sintered samples displayed a stable microstructure; however, relatively finer nanocrystalline grains are observed in dual-phase Gd 2 Zr 2 O 7 and (La 0.2 Gd 0.8 ) 2 Zr 2 O 7 samples. The combined influence of disorder-driven resistance offered by the fluorite phase and grain boundary pinning by the pyrochlore phase renders these systems highly suitable for applications demanding thermal stability and preservation of microstructural features.
Almeida et al. (Tue,) studied this question.