板状α-Al_2O_3制备过程中的影响因素

Influence Factors of Preparing α-Al_2O_3 Platelets

以AlF3作为添加剂,采用醇盐水解法制备板状α-Al2O3粉体.通过XRD、SEM、TG研究了热处理温度、AlF3加入量、水热温度对产物晶相及板状形貌的影响.研究结果表明:AlF3可使α-Al2O3相在800℃至900℃之间形成;一定水热温度下,随AlF3加入量增大,α-Al2O3的微观形貌是从不规则的板状多面体向规则的六角平板状发展;随水热温度升高,α-Al2O3微观形貌则由多面体结构向六角板状结构再到"蠕虫状"结构转变.

α-Al2O3 platelets are synthesized by a hydrolysis of alkoxide method introducing AlF3 additive. The effects of heat-treatement temperature, AlF3 concentration and hydrothermal temperature on the phase transformation and α-Al2O3 platelets are investigated by XRD, SEM and TG. A single phase of α-Al2 O3 is obtained at 800 -900 ℃ with AlF3 additive. The ix-Al2O3 passes through the morphology transformation of irregular platelet to flat hexangular platelet with increasing AlF3 concentration at the certain hydrothermal temperature, and the morphology of α- Al2O3 passes through the transformation of polyhedron to hexangular platelet to vermiform morphology with increasing hydrothermal temperature.