| 硅含量对Al2O3-SiO2气凝胶结构和性能的影响 | |
| Effect of Silica Content on Structure and Properties of Al2O3-SiO2 Aerogels | |
| 摘要: 研究了硅含量对Al2O3-SiO2气凝胶结构和性能的影响。结果表明，随着硅含量的增加，Al2O3-SiO2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SiO2过渡。Al2O3-SiO2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-Al2O3和SiO2，1 200 ℃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Al2O3-SiO2气凝胶的相变，其1 000 ℃的比表面积(339~445 mm2·g-1)高于纯Al2O3气凝胶(157 mm2·g-1)。SEM分析表明，硅元素的加入改变了Al2O3气凝胶的结构形貌，随着硅含量的增大，Al2O3-SiO2气凝胶逐渐由针叶状或长条状向球状颗粒转变。 | |
| 关键词: 气凝胶 勃姆石 莫来石 比表面积 | |
| 基金项目: | |
| Abstract: The effect of silica content on structure and properties of Al2O3-SiO2 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. Al2O3-SiO2 aerogel is constituted of Al-O, Si-O and Al-O-Si network. Aerogels convert to amorphous γ-Al2O3 and SiO2 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, Al2O3-SiO2 aerogels have larger surface area(339~445 m2·g-1) than pure alumina aerogel (157 m2·g-1) at 1 000 ℃. SEM shows that the microstructure of Al2O3 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. | |
| Keywords: aerogel boehmite mullite surface area | |
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| 冯 坚,高庆福,武 纬,张长瑞,冯军宗,姜勇刚.硅含量对Al2O3-SiO2气凝胶结构和性能的影响[J].无机化学学报,2009,25(10):1758-1763. | |
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