Novel Synthesis of Yb ₄ Zr ₃ O ₁₂ via Coprecipitation and Mechanical Activation for Improved Ceramic Mechanical Properties

ABSTRACT This study presents the first investigation of the effects of mechanical activation (MA) on the thermal decomposition of a coprecipitated ytterbium‐zirconium hydroxide precursor and the subsequent formation of Yb 4 Zr 3 O 12 over the temperature range of 600°C–1300°C. The process was characterized using Fourier‐transform infrared (FT‐IR) spectroscopy, thermal analysis, X‐ray diffraction (XRD), BET surface area measurements, and scanning electron microscopy (SEM)/transmission electron microscopy (TEM). Particular emphasis was placed on monitoring carbonization processes during precursor preparation and MA, as well as decarbonization and dehydration during subsequent heat treatment. It was demonstrated that calcination of both the initial and mechanically activated precursors in the temperature range of 600°C–1100°C results in the formation of nanocrystalline Yb 4 Zr 3 O 12 with a disordered fluorite cubic structure. The rhombohedral δ‐phase Yb 4 Zr 3 O 12 forms upon heat treatment of the precursors at temperatures of 1200°C–1300°C. Notably, the ytterbium zirconate powder derived from the MA‐precursor exhibits a higher BET‐specific surface area, lower microstrain, and better crystallinity compared to that synthesized from the initial precursor under identical calcination conditions. Ceramics fabricated from the MA‐precursor via sintering at 1300°C demonstrated a finer, more uniform grain structure and substantially improved mechanical properties, including an increase in microhardness (+41%), Young's modulus (+83%), and fracture toughness (+39%) compared to those produced from the non‐activated precursor.