Microwave-induced combustion synthesis and electrical conductivity of Ce1-xGdxO2-1/2x ceramics

Ce1-xGdxO2-1/2x nanopowder were successfully synthesized by microwave-induced combustion process. For the preparation, cerium nitrate, gadolinium nitrate hexahydrate, and urea were used for the microwave-induced combustion process. The process took only 30 min to obtain Ce1-xGdxO2-1/2x powders. The exo-endo temperature, phase identification, and morphology of resultant powders were investigated by TG/DTA, XRD, and SEM. The as-received Ce1-xGdxO2-1/2x powders showed that the average particle size ranged from 18 to 50 nm, crystallite dimension varied from 11 to 20 nm, and the specific surface area was distribution from 16 to 46 m(2)/g. As for Ce1-xGdxO2-1/2x ceramics sintered at 1450 degrees C for 3 h, the bulk density of Ce1-xGdxO2-1/2x ceramics were over 91% of the theoretical density, the maximum electrical conductivity, sigma(700 degrees C) = 0.017 S/cm with minimum activation energy, E-a = 0.869 eV was found at Ce0.80Gd0.20O1.90 ceramic. (C) 2006 Elsevier Ltd. All rights reserved.