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论文类型：期刊论文

发表时间：2015-10-01

发表刊物：JOURNAL OF WUHAN UNIVERSITY OF TECHNOLOGY-MATERIALS SCIENCE EDITION

收录刊物：SCIE、EI、ISTIC、Scopus

卷号：30

期号：5

页面范围：900-907

ISSN号：1000-2413

关键字：amorphous and paracrystalline silica; the structure models; NMR; Al-substituted

摘要：This work aimed to research the structure models of amorphous materials. Five amorphous and paracrystalline samples (natural or artificial) were investigated via Si-29/Al-27 nuclear magnetic resonance (NMR) and field emission scanning electron microscopy/energy dispersive spectroscopy (FE-SEM/EDS). The results of NMR showed the resonances of different specimens: -93.2 ppm, -101.8 ppm, -111.8 ppm for natural pozzolana opal shale (POS). These peaks were assigned to the Q(2)(2OH), Q(3)(OH)/Q(4)(1Al) and Q(4) respectively. The results of Al-27 MAS NMR indicated that Al substituted for Si site in tetrahedral existing in the POS, while the Al/Si atomic ratio in opal was low (around 0.04). For the alkali-silicate-hydrate gel, there were at least three resolved signals assigned to Q(0) and Q(1), respectively. For the fused silica glass powder, there were the primary signals centered about at the range from -107 to -137 ppm, which were assigned to Q(4) units. In addition, the peaks at around -98 and -108 ppm were corresponding to Q(3)(1OH) and Q(4) units existing in aerogel silica structure.