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通过共析技术,用硝酸铝九水化合物和四乙基正硅酸盐合成了具有不同化学成分的Al2O3-SiO2混合凝胶。通过X射线衍射技术和29Si金属-氧化铝-硅的核磁共振分析得到这些凝胶晶相演变的研究结果。测出了中间型Al-Si尖晶石相的晶格参数,所得数据显示,如不考虑所选混合凝胶的成分,尖晶石相的成分就没有变化。这些结果证实了略小于28%的SiO2量好象在Al-Si尖晶石结构中与γ-Al2O3共同作为固溶体。对化学计量莫来石的两种成分混合凝胶的莫来化反应进行了叙述。
Al2O3-SiO2 mixed gels with different chemical compositions were synthesized by eutectoid technique using aluminum nitrate nonahydrate and tetraethylorthosilicate. The results of the study of the evolution of these gel phases were obtained by X-ray diffraction and 29Si metal-alumina-silicon NMR. The lattice parameters of the intermediate Al-Si spinel phase were determined and the data obtained showed that the composition of the spinel phase did not change without considering the composition of the selected mixed gel. These results confirm that slightly less than 28% of the amount of SiO2 appears to work as solid solution with γ-Al2O3 in the Al-Si spinel structure. The mullitization reaction of a mixed gel of two components of stoichiometric mullite is described.