溶胶凝胶法制备碳化硅陶瓷材料及其性能的研究

Study on preparation and property of SiC ceramics by sol-gel

以甲基三乙氧基硅烷为原料,盐酸为催化剂,乙醇为溶剂在一定的条件下制备二氧化硅溶胶,再与竹炭粉、硅粉按照一定的比例充分混合均匀,在Ar气氛下经高温烧结制得SiC陶瓷材料。借助FT-IR、SEM-EDS和XRD等测试方法对转变为SiC过程中的物理化学结构变化、显微结构和物相变化进行了表征,并对其吸附性能和导电性能进行了试验。试验结果表明,在竹炭转变为SiC的高温处理过程中,化学键Si—O键基本上全部转变为Si—C键;竹炭的显微结构很好的留在了SiC陶瓷中;竹炭SiC陶瓷材料是一种包含单质Si、C和SiC多相组分的复合材料。在1650℃条件下的SiC陶瓷材料的吸附能力比其它两个要高;竹炭SiC材料具有较低的电阻率,是一种半导体材料。

This experiment used MTES as raw materials,HCl as catalyzers,and C2H5OH as solvent to prepare SiO2 sol under certain condition. Then it mixed bamboo charcoal powder,silica powder and SiO2 sol in terms of definite proportion,and resulted in the formation of SiC ceramic in static argon atmosphere. FT-IR,SEM-EDS and XRD were employed to characterize the physico-chemichal structure changes,microstructure and phase changes during bamboo charcoal-to-SiC ceramics conversion. And the adsorption and resistance were studied at the same time.The results showed that during high-temperature processing,chemical bond was totally transformed from Si—O to Si—C,the microstrcture details of the bamboo were retained in SiC ceramics,and the SiC ceramics prepared by this technique are multi-phase solids composed of SiC,free-silicon and C. And SiC ceramics at 1650℃ had higher adsorption capability than others’. The ceramics were semiconductor materials,which had lower resistivity.