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依据新的固相反应模型,采用非等温热重和差示扫描量热法研究了由BaCO3和Co3O4、Fe2O3、Nb2O5粉末固相反应合成Ba1.0Co0.7Fe0.2Nb0.1O3-δ的动力学.考察了高速机械搅拌方式混料和球磨方式混料对合成动力学的影响.结果表明,反应过程分为两个阶段:第一阶段为BaCO3和Co3O4、Fe2O3、Nb2O5之间的加成反应;第二阶段为加成反应生成的BaCoO3、BaFeO3和BaNbO3三相之间固溶生成均相的Ba1.0Co0.7Fe0.2Nb0.1O3-δ,此过程中伴随有氧的脱出.应用修正的模型对实验结果进行了拟合,实验数据和理论模型符合良好.高速机械搅拌样品加成反应阶段的活化能为376.76kJ·mol-1,仅为球磨样品加成反应阶段活化能494.76kJ·mol-1的3/4.高速机械搅拌工艺促进了离子的扩散,有利于后续反应的进行,是更为有效、节能、环保的混料方式.
According to the new solid-phase reaction model, the kinetics of Ba1.0Co0.7Fe0.2Nb0.1O3-δ synthesis by solid-state reaction of BaCO3 and Co3O4, Fe2O3 and Nb2O5 powders was investigated by non-isothermal thermogravimetry and differential scanning calorimetry The effects of high speed mechanical mixing method and ball milling method on the synthesis kinetics were investigated.The results showed that the reaction process was divided into two stages: the first stage was the addition reaction between BaCO3 and Co3O4, Fe2O3 and Nb2O5; In the second stage, Ba1.0Co0.7Fe0.2Nb0.1O3-δ is formed by solid solution between the three phases of BaCoO3, BaFeO3 and BaNbO3 formed by the addition reaction, accompanied by the oxygen evolution. The experimental data are fitted well and the experimental data are in good agreement with the theoretical model.The activation energy of the high-speed mechanical agitation sample is 376.76 kJ · mol-1, and the activation energy of the addition reaction stage is 494.76 kJ · mol-1 Of the 3 / 4. High-speed mechanical mixing process to promote the diffusion of ions is conducive to the follow-up reaction is more effective, energy saving, environmentally friendly mixing methods.