【摘要】 采用TG-DSC热分析仪,对碳热还原法合成TiB2的反应混合物进行了热重分析,采用全程等温热重法,对碳热还原法合成TiB2的反应过程进行了动力学研究,并对反应产物进行了XRD分析。研究结果表明,碳热还原法合成TiB2的反应过程分为三个阶段:第一个阶段试样单位面积的失重与反应时间成抛物线关系,反应速率由碳的扩散过程所控制,反应的表观活化能为168.36kJ/mol;第二阶段试样单位面积的反应失重与时间成线性关系,反应速率由化学反应速率所控制,反应的表观活化能为165.28kJ/mol;第三阶段试样单位面积的失重与反应时间成抛物线关系,这一阶段的反应速率由碳的扩散过程所控制,反应的表观活化能为218.47kJ/mol。更多还原

【Abstract】 By using TG-DSC thermal analysiser,the thermogravimetric analysis of reaction mixture of sinthesizing TiB2 by carbothermal reduction was carried out.By using omnirange isothermal thermogrametic method and XRD analysis,the reaction kinetics of synthesizing TiB2 powder by carbothermal reduction was studied.The approach discoveried that the whole reaction course of carbothermal reduction to synthesize TiB2 can be divided into three stage: at the first stage,the relation between the weight loss of unit area sample and reaction time was parabolic,the reaction rate was controlled by the diffusion of carbon and the activation energy was 168.36kJ/mol;at the second stage,the relation between the weight loss of unit area sample and reaction time was linear,the reaction rate was controlled by chemical reaction and the activation energy was 165.28kJ/mol;at the third stage,the relation between the weight loss of unit area sample and reaction time was parabolic,the reaction rate was controlled by the diffusion of carbon and the activation energy was 218.47kJ/mol.更多还原