CAJ | 학술논문

研究了硅含量对Al_2O_3-SiO_2气凝胶结构和性能的影响.结果表明,随着硅含量的增加,Al_2O_3-SiO_2溶胶的凝胶时间逐渐延长,气凝胶密度逐渐增大.其结构逐渐由多晶勃姆石向无定形SiO_2过渡.Al_2O_3-SiO_2气凝胶同时含有Al-O、Si-O以及Al-O-Si结构,600 ℃煅烧后的物相为无定形γ-Al_2O_3和SiO_2,1 200 ℃煅烧后为莫来石相.当硅含量为6.1wt%～13.1wt%时,适量的硅抑制了Al_2O_3-SiO_2气凝胶的相变,其1 000℃的比表面积(339～445 m2·g~(-1))高于纯Al_2O_3气凝胶(157 m~2·g~(-1)).SEM分析表明,硅元素的加入改变了Al_2O_3气凝胶的结构形貌,随着硅含量的增大,Al_2O_3-SiO_2气凝胶逐渐由针叶状或长条状向球状颗粒转变.
연구료규함량대Al_2O_3-SiO_2기응효결구화성능적영향.결과표명,수착규함량적증가,Al_2O_3-SiO_2용효적응효시간축점연장,기응효밀도축점증대.기결구축점유다정발모석향무정형SiO_2과도.Al_2O_3-SiO_2기응효동시함유Al-O、Si-O이급Al-O-Si결구,600 ℃단소후적물상위무정형γ-Al_2O_3화SiO_2,1 200 ℃단소후위막래석상.당규함량위6.1wt%～13.1wt%시,괄량적규억제료Al_2O_3-SiO_2기응효적상변,기1 000℃적비표면적(339～445 m2·g~(-1))고우순Al_2O_3기응효(157 m~2·g~(-1)).SEM분석표명,규원소적가입개변료Al_2O_3기응효적결구형모,수착규함량적증대,Al_2O_3-SiO_2기응효축점유침협상혹장조상향구상과립전변.
The effect of silica content on structure and properties of Al_2O_3-SiO_2 aerogels was investigated. The results show that with the increase in silica content, the gelation time of the sol is prolonged, the density of aerogel is increased, and the structure is changed from crystal boehmite to amorphous silica. Al_2O_3-SiO_2 aerogel is constituted of Al-O, Si-O and Al-O-Si network. Aerogels convert to amorphous γ-Al_2O_3 and SiO_2 after 600 ℃ calcination, and transformed to mullite at 1 200 ℃. When silica content is 6.1wt%～13.1wt%, as a result of the suppression of the phase transformation, Al_2O_3-SiO_2 aerogels have larger surface area (339～445 m~2·g~(-1)) than pure alumina aerogel (157 m~2·g~(-1)) at 1 000 ℃. SEM shows that the microstructure of Al_2O_3 aerogel is changed by the addition of silica. With the increase in silica content, the shape of aerogel particle is changed from acicular or clubbed into spherical.