摘要
以硝酸锆为前驱体,二氧化硅为晶型稳定剂,采用溶胶-凝胶法在多孔氧化铝载体上制备了无缺陷的硅锆复合膜.借助TG-DTA、XRD、BET、SEM、TEM和AFM等测试手段对膜的表面形貌、孔径分布以及热稳定性进行了分种析和表征.实验结果表明,硝酸锆比氧氯化锆更适合作前驱体,可获得均匀分布的稳定溶胶;当二氧化硅含量为25%（摩尔百分数）时,可以得到平整无缺陷的硅锆复合膜;焙烧过程中,不同升温区间须采用不同的升温速率,以防止膜的开裂;由于二氧化硅与氧化锆间的相互作用,抑制了氧化锆晶型的转变,同时也提高了二氧化硅的晶化温度.硅锆复合膜在700～900℃范围内保持单一的氧化锆四方晶型,晶粒大小几乎不随温度变化,具有良好的热稳定.
The defect-free silica-zirconia composite membrane was prepared by sol-gel method, The surface morphology, pore size distribution and crystal structure of the membrane were investigated by using thermogravimetric analysis and differential thermal analysis （TGA-DTA）, X-ray diffraction （XRD）, gas adsorption analyzer （BET）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM） and atomic force microscopy （AFM）, etc. The zirconium nitrate is more suitable to be used as the precursor than zirconium oxyehloride to get stable zirconyl oxalate sol with uniform particles. Silica was used as the stabilization agent. The defect-free composite membrane was obtained when 25% silica （in volume） is added. Pure zireonia is ready to transform from tetragonal to monoelinie phase at 600-650℃, however, the crystal transformation is prohibited by the interaction between silica and zireonia, which also leads to increase the crystallization temperature of the silica. The preliminary results demonstrate that only tetragonal zirconia appears at 700-900℃, and the size of which does not change with temperature.
出处
《高校化学工程学报》
EI
CAS
CSCD
北大核心
2006年第3期443-448,共6页
Journal of Chemical Engineering of Chinese Universities
基金
国家自然科学基金项目(50228203和20476076)。
关键词
硝酸锆
硅胶
溶胶-凝胶法
复合膜
热稳定性
zirconium nitrate
silicon sol
sol-gel method
composite membrane
thermal stability
