CaO-MgO-Al_2O_3-SiO_2-P_2O_5-F系微晶玻璃初晶相Ca_5(PO_4)_3F析晶过程的研究

Study on the Precipitation Process of Ca_5(PO_4)_3F in CaO-MgO-Al_2O_3-SiO_2-P_2O_5-F Glass-Ceramic

本文应用透射电镜:选区电子衍射和微区成份分析并结合扫描电镜形貌观察,深入研究了 CaO-MgO-Al_2O_3-SiO_2-P_2O_5-F 系可切削生物微晶玻璃初晶相 Ca_5(PO_4)_3F 的析晶机理。研究表明,玻璃首先发生二液分离,形成了能够析出初晶相 Ca_5(PO_4)_3F 晶体的富 P^(5+)、Ca^(2+)、Mg^(2+)、Ti^(4+)的液滴相。在进一步的热处理中,液滴相发生整体核化,并逐步形成由大量细小晶粒镶嵌生长构成的球形 Ca_5(PO_4)_3F 聚集体。随着热处理温度的提高,这些球形 Ca_5(PO_4)_3F 聚集体逐渐转变为广泛分布于微晶玻璃另一主晶相氟金云母中的六方短柱状 Ca_5(PO_4)_3F 微小晶体。

The precipitation process of initial crystallized phase Ca_5(PO_4)_3 F of a machineable bioactive glass-ceramic in the CaO-MgO-Al_2O_3-SiO_2-P_2O_5-F system was studied by means of TEM,SEM,EDAX and selected area electron diffractiontechniques.It shows that the parent glass has two-phase separation structure,andthe droplet phase is rich in P^(+5),Ca^(2+),Mg^(2+)and Ti^(4+).Heat-treatment of theglass leads to bulk crystallization of the droplet phase,forming a large number ofspherical fluor apatite aggregates embeded in glassy matrix.As the heat-treatmenttemperature is increased,they change gradually into short hexa-prismatic fluorapatite microcrystals dispersed in fluor phlogopite,the other main crystal phase ofthe glass-ceramic.