(西安建筑科技大学 材料与矿资学院，西安 710055)
摘 要: 在XRD、SEM、能谱分析、TEM、TG-DSC等实验分析的基础上，对以TiO2、B2O3、C为原料，通过碳热还原法合成TiB2粉末的反应传质机理进行了研究，阐明碳热还原法合成TiB2的反应传质机理，建立碳热还原法合成TiB2的反应传质模型。研究表明：在碳热还原TiO2的过程中，由低温到高温，最稳定的还原产物分别是Ti4O7和Ti3O5，尤其当温度超过1300℃以后，Ti3O5为最稳定的还原产物。在碳热还原TiO2与B2O3合成TiB2的反应过程中，DDSC曲线上有几个明显的吸热峰，这分别对应于TiO2→Ti4O7→Ti3O5→TiB2的反应阶段。碳与氧化物颗粒之间是通过CO/CO2气体偶实现质量传递的。在反应体系中，B2O2(g)气相、Ti3O5(s)固相分别是形成TiB2的前驱体。
关键字: TiB2；碳热还原；传质机理；传质模型
（College of Materials and Mineral Resources, Xi’an University of Architecture and Technology, Xi’an 710055, China）
Abstract:On the basis of experiment analysis such as XRD, SEM, energy spectrum analysis, TEM and TG-DSC, the reactionary mass transfer mechanism of synthesizing TiB2 by carbothermal reducing TiO2 and B2O3 was studied. The reactionary mass transfer mechanism of synthesizing TiB2 by carbothermal reduction method was analyzed, and the reactionary mass transfer model of synthesizing TiB2 by carbothermal reduction method was built. The results show that, during carbothermal reduction of TiO2, the most stable reduction products are Ti4O7 and Ti3O5 from low temperature to high temperature, respectively, when the reduction temperature is over 1 300 ℃, Ti3O5 is the most stable reduction product.There are several endothermic peaks on DDSC curve in the process of synthesizing TiB2 by carbothermal reducing TiO2 and B2O3, which correspond to reaction stage of TiO2→Ti4O7→Ti3O5→TiB2, respectively. The mass transfer from carbon to the oxide particle is realized by the CO/CO2 gas couple. In reactionary system, B2O2(g) and Ti3O5(s) are the precursors of formation TiB2 by carbothermal reduction.
Key words: TiB2; carbothermal reduction; mass transfer mechanism; mass transfer model
