添加P_2O_5及F对CaO-MgO-Al_2O_3-SiO_2系微晶玻璃形成及析晶的影响

Glass Constitution and Crystallization Characteristics of CaO-MgO-Al_2O_3-SiO_2 Glass-Ceramic with P_2O_5 and F Additions

为了研究P_2O_5及氟化物对CaO-MgO-Al_2O_3-SiO_2系微晶玻璃形成及析晶的影响,采用高温熔融法制备了不同P_2O_5及氟化物含量的玻璃试样。结果表明:玻璃的形成范围大致为(P_2O_5%+F%)≤10%。在氟化物的添加量较低时,试样仅发生表面析晶,析出晶体为硅灰石(CaSiO_3)和少量的钙长石(CaAl_2Si_2O_8)。随着氟化物含量是增加,试样在表面和内部都析出晶体,最终形成"整体"析晶的状态。P_2O_5的加入抑制了表面析晶,但促进了玻璃的分相和整体析晶。同时添加P_2O_5及氟化物将促进晶体的整体析出和晶体的生长,P_2O_5加入量的提高有利于氟磷灰石[Ca_5(PO_4)_3F]的析出,而氟化物含量的提高增加了钙长石的析出。

To explore the effects of the additions of P2O5 and fluorine on the glass formation region and crystallization in CaO-MgO-Al2O3-SiO2 glass, the base glasses were prepared by melt-quenching methods and the crystallizing behavior were investigated by using XRD and SEM techniques. The results indicate that the glass formation region is around （P205%＋F%） 〈10%. In the sample with 4.0% in mass fraction of fluorine surface-dominated crystallization is suggested and the crystalline phases of anorthite （CaAl2Si2O8） as the major phase and wollastonite（CaSiO3） minor phase are precipitated. With the increase of fluorine contents, both surface and bulk crystallization are observed, forming the ＂volume＂ crystallization finally. The incorporation of P2O5 suppresses the surface crystallization, but inducing the appearance of phase-separation and bulk crystallization. When P2O5 and fluorine in combination are employed into the glasses, the bulk crystallization with fluoroapatite （Ca5（PO4）3F） and anorthite as the main phases is obtained, in which, the increase of P2O5 contents is beneficial to the forming of fluoroapatite, while the increase of fluorine content is favor to the precipitation of anorthite.