ZrF_4-BaF_2-LaF_3-ZnF_2系统玻璃的析晶行为和动力学

Crystallization Behavior and Kinetics of ZrF_4-BaF_2-LaF_3-ZnF_2 System Glasses

用DTA和XRD分析、TEM观察、IR光谱以及等温和不等温DSC等方法,研究了61.5ZrF_4·(31-m)BaF_2·7.5LaF_3·mZnF_2玻璃(m=0～6%(mol))的晶化过程和析晶动力学。结果表明:该系列玻璃是由分相导致整体析晶,DTA曲线上的T_(c1)峰为β-BaZrF_6和β-BaZr_2F_(10)晶相的共同析晶峰,DTA曲线上的T_(c2)峰为LaF_3·2 zrF_4晶相的析出峰和β-BaZrF_6→α-BaZrF_6多晶转变峰;玻璃的析晶动力学过程可以用JMA方程来描述;以适量的ZnF_2取代BaF_2可使玻璃的形成能力有所改善。

With the help of DTA, XRD, TEM, IR spectra and DSC, the crystallization behavior and kinetics of 61.5 ZrF_4-(31-m)BaF_2-7.5 LaF_3-m ZnF_2 system glasses (m=0～6mol%) were studied. The results demonstrated that phase separation plays the role of precursor of crystallization, the first exothermal peak (T_(C1)) on the DTA curve is caused by the formation of β-BaZrF_6 and β-BaZr_2F_(10), the second exothermal peak (T_(C2)) belongs to the formation of LaF_3·2 ZrF_4 and the transformation of β-BaZrF_6 to α-BaZrF_6. Their crystallization kinetics process can be described by JMA equation and the glass forming ability may be improved by replacing BaF_2 with appropriate amount of ZnF_2.