Synthesis and characterization of phase pure barium zirconate nanoceramics by citrate acetate using the sol-gel process grown at reduced temperatures

Abstract

Barium zirconate (BaZrO₃) has been pursued for chemically inert, refractory materials with high mechanical and thermal stability and its nanoparticles are attractive for various dielectric applications. BaZrO₃ is mainly synthesized under high temperatures, beyond the thermal budget for large-scale production. The high-quality phase pure material synthesis with nanoscale particle size at reduced temperature is a key challenge. In this work, phase pure BaZrO₃ have been synthesized at temperatures down to 800 °C via a sol-gel auto-combustion technique using acetate salts of the metal precursors (barium acetate and zirconium acetate) and citric acid. The work highlights the necessity of improving metal precursor flux for the formation of nano-size synthesis of BaZrO₃ at a relatively lower temperature compared with that of the standard solid-state reaction process. The influence of synthesis temperature on crystallographic structure and crystallite size of the synthesized samples have been studied using powder x-ray diffraction (p-XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) at room temperature. The optimized sample synthesized at 800 °C exhibits a cubic structure with a crystallite size of 12.1 nm as calculated from the XRD refinements, which is one of the lowest reported among sol-gel auto combustion techniques. The crystallite size mentioned above is consistent with the FESEM particle size analysis. Furthermore, the sintered pellet obtained from the optimized powder sample has shown good bulk density of around (92–95) %.