现代连续相变理论在玻璃分相中的应用——碱土金属硅酸盐二元系统分相的普适性及定量计算

APPLICATION OF THE MODERN CONTINUOUS PHASE TRANSITION THEORY TO PHASE SEPARATION IN GLASSES——THE QUANTITATIVE CALCULATION OF PHASE SEPARATION AND ITS UNIVERSALITY IN BINARY ALKALINE-EARTH SILICATE SYSTEMS

本文用现代连续相变理论对稳态分相的碱土金属硅酸盐二元系统SiO_2-RO(R=Mg,Ca,Sr)的分相进行了分析。这些系统的分相值经过对临界点的标度,发现其标度实验值都在同一标度主曲线附近。相应它们临界点两侧的分相曲线,可普适地由以下两表达式定量表示:(x-x_c)/x_c=A(T_c-T)/T_c)^(1/3),(x′-x_c)/x_c=A′(T_c-T)/T_c)^(1/3)。这里A、A′是分相普适常数。本文从这三个系统分相实验值的拟合结果是A=-1.8180,A′=3.2215,并对此结果与从亚稳分相系统得到的普适常数有所不同作了初步分析。预计本文的结果在一定程度上可普适于其它系统的分相。

The stable phase separation of binary alkaline-earth silicates SiO_2-RO(R=Mg, Ca, Sr) is analyzed by means of the modern continuous phase transition theory in this paper. It can be seen that, with the normalization of the critical points, all experimental data points are in the neighbourhood of a main curve. Futhermore, their phase separation curves at two sides of the critical points can be universally calculated by the following two equations:(x-x_c)/_c=A[(T_c-T)/T_c]^(1/2);(x′-x_c)/x_c=A′[(T_c-T)/T_c]^(1/2), where A and A′ are universal constants of immiscible curves. The universal constants obtained in the curve fitting of the experimental data of the three systems are A=-1.8180, A′=3.2215. The difference between the above results and the results obtained from metastable phase separation is also discussed. It is estimated that the results of this paper can be used for the phase separation of other systems in certain conditions.