摘要
The difference of intermediate products,microstructure and element concentration in the particles between microwave synthesized samples and conventional samples was responsible for the existence of non-thermal effect in the microwave field.The diffusions of Ba2+,Ti4+ in the microwave field were enhanced,so that the diffusion of Ti4+ could not be neglected as in the conventional solid state reactions.The influences of the microwave field were mainly expressed as diffusion coefficient and the driving force of ionic motion.The intermediate phase Ba2TiO4 which occurred in the conventional solid reaction was not found during microwave syntheses.The quantity analyses based on XRD experimental data show that the reaction dynamics in microwave is suitable for the Carter equation.The activity energy for reaction of BaCO3 and TiO2 in the microwave field was 42.26 kJ/mol,which was only one fifth of the conventional reaction.
The difference of intermediate products,microstructure and element concentration in the particles between microwave synthesized samples and conventional samples was responsible for the existence of non-thermal effect in the microwave field.The diffusions of Ba2+,Ti4+ in the microwave field were enhanced,so that the diffusion of Ti4+ could not be neglected as in the conventional solid state reactions.The influences of the microwave field were mainly expressed as diffusion coefficient and the driving force of ionic motion.The intermediate phase Ba2TiO4 which occurred in the conventional solid reaction was not found during microwave syntheses.The quantity analyses based on XRD experimental data show that the reaction dynamics in microwave is suitable for the Carter equation.The activity energy for reaction of BaCO3 and TiO2 in the microwave field was 42.26 kJ/mol,which was only one fifth of the conventional reaction.
基金
Project supported by the National Natural Science Foundation of China.
