SiO_2含量对氧化铁基Fe_2O_3-SiO_2二元复合干凝胶性能的影响

Effect of SiO_2 Addition on the Properties of Fe_2O_3-SiO_2 Binary Composite Xerogels

以水合氯化铁和正硅酸乙酯为前驱物,通过溶胶-凝胶法制备不同SiO_2含量的氧化铁基Fe_2O_3-SiO_2二元复合凝胶,利用冷冻干燥法对凝胶进行干燥得到复合干凝胶。分别采用BET、IR和SEM对复合凝胶的比表面积、孔结构、红外吸收峰和表面形貌进行分析。结果表明,复合凝胶的比表面积和孔体积随着SiO_2含量的增加而增加,同时SiO_2的引入改变了Fe_2O_3凝胶的骨架结构,使得Fe_2O_3凝胶中部分Fe-O-Fe键与Si原子形成一定数量的Fe-O-Si键,形成了以Fe_2O_3为主要基体的Fe_2O_3-SiO_2复合凝胶。SiO_2的引入有效提高了复合凝胶的比表面积,改善了凝胶的孔结构,为制备二元复合凝胶为骨架的高能纳米铝热剂奠定基础。

The iron oxide-based Fe_2O_3-SiO_2 binary composite xerogels were prepared by sol-gel and freeze-drying method using FeCl_3·6H_2O and TEOS as precursors.The pore structure and specific surface area of the binary xerogels were investigated by means of nitrogen adsorption experiments,FT-IR spectroscopy and SEM.The results show that the specific surface area and the pore volume increase with the silica content,which is caused by Fe-O-Si bonds formed in the binary xerogels.The addition of SiO_2 improves the specific area and pore structure of the binary composite xerogels.These will provide a basis for their application in the nano-thermite.