Synthesis of nanocrystalline yttria by microwave-assisted citrate-gel decomposition technique

Nanocrystalline yttria powders were prepared using microwave-assisted heating citrate-gel decomposition technique for the first time. The process involved the reaction between yttrium nitrate (oxidizer) and citric acid (fuel) under the heat generated by absorbing microwaves. The precursor powder was investigated by thermogravimetry (TG) and differential scanning calorimetry (DSC) analyses. These prepared precursor powders were calcined at 1100 °C for 4 h. The precursor powders and calcined powders were characterized by Brunauer–Emmett–Teller (BET) surface area, X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses to study the structure and powder morphology. The calcined powders were found to be single-phase cubic crystalline yttria. The particle sizes in the range of 30–100 nm were observed for calcined powders.