Effect of CeO2 on the reaction kinetics for the formation of Sr0.5Ba0.5CexNb2O6+δ

The solid-state reaction of SrNb2O6, BaNb2O6, and CeO2 to form Sr0.5Ba0.5CexNb2O6+delta at different temperatures and heating rates was investigated. A nonisothermal kinetic empirical model was used to evaluate the activation energy and rate constant of Sr0.5Ba0.5CexNb2O6+delta. The values of the activation energy evaluated from the slopes are 762, 800, and 844 kJ/mol, respectively, for S50, 1CeS50, and 2CeS50, which increase with the increase in Ce doping. The order of reaction was found to decrease with the increase of the Ce doping. A kinetic equation was developed based on the parameters evaluated from the nonisothermal reaction model, which was successfully used to predict the isothermal reaction of Ce-doped strontium barium niobate.