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以五氯化钽(TaCl5)、正硅酸乙酯(TEOS)和葡萄糖(C6H12O6 H2O)为原料制备了葡萄糖复合凝胶,凝胶经过450℃煅烧得到C-SiO2-Ta2O5杂化前驱体,通过碳热还原前驱体,于1200～1500℃合成了SiC-TaC纳米复合粉体,并用X射线衍射扫描电镜和能谱仪对产物进行表征。结果表明:凝胶中无定型的SiO2和Ta2O5可通过Si—O—Ta键合,均匀分布的Si—O—Ta—C长链使得杂化前驱体内部结合成为牢固的互穿网络结构;TaC于1200℃时得到,而SiC可在1400℃开始合成,反应可在1500℃完成。在不同的钽硅摩尔比下,SiC-TaC纳米复合粉体具有差异性形貌。当钽硅比约为0.02时,SiC与TaC纳米晶粒颗粒分布均匀,同质化明显。随着钽硅比的升高,SiC有从球状转变为纳米线状的趋势。
The glucose complex gel was prepared from tantalum chloride (TaCl5), TEOS and glucose (C6H12O6 H2O), and the gel was calcined at 450 ℃ to obtain C-SiO2-Ta2O5 hybrid precursor The carbothermal reduction precursor was used to synthesize SiC-TaC nanocomposite powders at 1200-1500 ℃. The products were characterized by X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. The results show that the amorphous SiO2 and Ta2O5 in the gel can be bonded to Si-O-Ta-C through a Si-O-Ta long chain with uniform Si-O-Ta bonds to form a strong interpenetrating network structure. TaC Obtained at 1200 ℃, and SiC can start synthesis at 1400 ℃, the reaction can be completed at 1500 ℃. SiC-TaC nanocomposite powders have different morphologies at different mole ratios of tantalum and silicon. When the ratio of tantalum to silicon is about 0.02, the distribution of SiC and TaC nano-particles is uniform and the homogenization is obvious. With the increase of tantalum to silicon ratio, SiC tends to change from spherical to nanowire.