Effect of CeO₂ on the reaction kinetics for the formation of Sr_0.5Ba_0.5Ce_xNb₂O_6+δ

The solid-state reaction of SrNb₂O₆, BaNb₂O₆, and CeO₂ to form Sr_0.5Ba_0.5Ce_xNb₂O_6+δ at different temperatures and heating rates was investigated. A nonisothermal kinetic empirical model was used to evaluate the activation energy and rate constant of Sr_0.5Ba_0.5Ce_xNb₂O_6+δ. 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.