流态化CVD制备TiO_2－Al_2O_3复合粒子

Preparation of TiO_2-Al_2O_3 Composite Particles by Fluidized Chemical Vapor Deposition Technology

本文探讨了流态化ＣＶＤ反应器中Ｔｉ（ＯＣ４Ｈ９）４水解制备ＴｉＯ２－Ａｌ２Ｏ３复合粒子新工艺，借助于ＳＥＭ、ＴＥＭ、ＢＥＴ、ＸＲＦ和ＥＰＭＡ等现代测试手段研究了复合粒子结构和包覆过程特征．结果表明，在流态化ＣＶＤ反应器中Ａｌ２Ｏ３超细颗粒以团聚体形式存在，ＴｉＯ２包覆量随Ｔｉ（ＯＣ４Ｈ９）４进料浓度升高而增加，但反应温度影响不大；在包覆过程中，同时存在成核和成膜，成核包覆使复合粒子比表面积增加，成膜包覆使复合粒子比表面积减小．

Composite TiO2-Al2O3 particles were prepared by hydrolyzation of Ti(OC4H9)4 in fluidised CVD reactor. Simultaneously SEM, TEM, BET and EPMA etc. were successfully used to study the structures of composite particles and the characteristic of coating process. The results indicated that Al2O3 ultrafine powders existed in the fluidized CVD reactor as clusters, and concentration of reactant afected the coating obviously instead of reaction temperature. Nucleation and film-forming were coexisted during the process of coating, nucleation promotes the increase of surfaces of composite palticles, however filmforming induces to surf ases decrease.