Correlation between structure and electrical properties of conventionally sintered ZrO₂-Gd₂O₃ ceramics

Rare-earth zirconates attract attention as promising materials for the fabrication of thermal barrier coatings, catalysts, sensors, and ionic conductors due to their crystal structure and unique physicochemical properties. Gadolinium zirconate stands out among these compounds owing to its high thermal stability, radiation resistance, chemical stability, etc. In the present study, ZrO_2 and Gd_2O_3 powders were mixed in a molar ratio that corresponds to the compound Gd_2Zr_2O_7 , and mechanically activated in a Gd_2Zr_2O_7 high-energy ball mill for 15, 30, or 60 min. Pellets were then sintered conventionally in air, from 1200-1600?C for 2h. Phase composition and microstructure of milled powders and sintered specimens were characterized. Phase-pure Gd_2Zr_2O_7 was obtained after sintering at 1600?C for non-activated powder and at 1400?C for the powder activated for 60 minutes. Densities and microstructures after sintering were correlated with electrical measurements (dielectric permittivity and loss tangent).