混合碱效应对Li2O-Al2O3-SiO2系玻璃结构和热膨胀性能的影响

本文用传统高温熔融法熔制Li₂O-Al₂O₃-SiO₂系高铝玻璃,改变碱金属氧化物n(Li₂O)/n(Na₂O)的摩尔比,运用阿基米德排水法、热膨胀仪、DSC、傅里叶变换红外光谱和拉曼光谱等测试手段和仪器,探究了混合碱金属效应对Li₂O-Al₂O₃-SiO₂系玻璃结构和热膨胀性能的影响。结果显示:随着n(Li₂O)/n(Na₂O)比例增大,混合碱金属效应对Li₂O-Al₂O₃-SiO₂系玻璃的密度和热膨胀系数的影响一致,表现为先增大后减小,当R=0.25(R=n(Li₂O)/[n(Li₂O)+n(Na₂O)],摩尔比)时,出现极值,此时密度达到最大2.447 4 g/cm³,热膨胀系数达到最大7.811 7×10^-6/℃;对玻璃特征温度的影响随着温度的升高而逐渐减弱至消失;对玻璃的析晶能力有一定的提升作用;对玻璃三维骨架结构中的硅氧四面体Qⁿ的影响也各不相同。

Influence of Mixed Alkali Effect on Structure and Thermal Expansion Properties of Li2O-Al2O3-SiO2 Glass

In this paper, the Li₂O-Al₂O₃-SiO₂ high alumina glass was melted by traditional high temperature melting method, and the mole ratio of alkali metal oxide n(Li₂O)/n(Na₂O) was changed. The influence of mixed alkali metal effect on the structure and thermal expansion performance of Li₂O-Al₂O₃-SiO₂ glass was investigated by Archimedes drainage method, thermal expansion instrument, DSC, Fourier transform infrared spectroscopy and Raman spectroscopy. The effects on the structure and thermal expansion properties of Li₂O-Al₂O₃-SiO₂ glasses are different. Results show that with the increase of n(Li₂O)/n(Na₂O) mole ratio, the mixed alkali metal effect has the same effect on the density and thermal expansion coefficient of Li₂O-Al₂O₃-SiO₂ glass, which increases first and then decreases, When R=0.25(R=n(Li₂O)/[n(Li₂O)+n(Na₂O)], mole ratio) has a maximum value, the maximum density is 2.447 4 g/cm³, and the maximum thermal expansion coefficient is 7.811 7×10^-6/℃. The influence on the characteristic temperature of glass gradually weakens and disappears with the increase of temperature. It can promote the crystallization behavior of glass to some extent.The influences on the silicon-oxygen tetrahedron Qⁿ in the three-dimensional skeleton structure of glass are also different.