Li Jinhong, Tong Lingxin, Wang Xiang
J Nanosci Nanotechnol. 2014 May;14(5):3876-9. doi: 10.1166/jnn.2014.7940.
Nano mullite powders have been synthesized from calcined kaolin via open hydrothermal process. The powder product was characterized by X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM) with selected area electron diffraction (SAED) analysis. The results indicated that single phase puncheon-shaped nano mullite with about 140-360 nm in length and 50-80 nm in diameter is produced when synthesized in 4 mol/L NaOH solution at 100 degrees C for 4 h. The grain size of mullite decrease slightly with increasing reaction time from 0 h to 4 h. In addition, nuclear magnetic resonance (NMR) analysis confirms presence of Al3+ during the whole reaction process, which indicates that there is an absence of growth units of mullite in the open hydrothermal system and the mullite precursor mainly underwent a solution process during open hydrothermal treatment.
通过开放水热法由煅烧高岭土合成了纳米莫来石粉末。采用X射线衍射（XRD）分析、扫描电子显微镜（SEM）、带有选区电子衍射（SAED）分析的透射电子显微镜（TEM）对粉末产物进行了表征。结果表明，在100℃的4mol/L氢氧化钠溶液中合成4小时时，可制备出长度约为140 - 360nm、直径为50 - 80nm的单相短棒状纳米莫来石。从0小时到4小时，随着反应时间的增加，莫来石的晶粒尺寸略有减小。此外，核磁共振（NMR）分析证实了在整个反应过程中存在Al3+，这表明在开放水热体系中不存在莫来石的生长单元，并且莫来石前驱体在开放水热处理过程中主要经历了溶解过程。
