摘要
采用差热分析(DTA)和淬冷技术,结合X衍射(XRD)及偏光显微镜物相分析,系统地研究了Na_3AlF_6-AIF_3二元系相图,结果表明该二元系含有亚冰晶石(Na_5Al_3F_(14))与单冰晶石(NaAlF_4)两个非同分化合物,前者是Na_3AlF_6与液相735℃下的包晶产物;后者是AlF_3与液相707℃下的包晶产物,仅在550—707℃温度范围内存在。Na_5Al_3F_(14)与NaAlF_4在37.5wt％AlF_3处形成共晶,共晶温度690℃。
The phase diagram of Na3AlF6-AlF3 system was systematically studied by means of DTA and X-ray powder diffraction together with quenching technique and microscopy. The results indicated that there exist two incongruent compounds, Na5Al3F14 and NaAlF4 in this system, they are formed by solid Na3AlF6 and A1F3 reacting with the liquid phase at 735 ℃ and 707℃, respectively. But NaAlF4 was found only in a temperature range from 550 to 707℃. The eutectic point of Na5Al3Fn and NaAlF4 is at 690℃ and 37.5 wt% AlF3.
