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Ba O–Si O2体系是Ba O–Lu2O3–Si O2三元系相图的一个重要的边二元系。基于实验相图和热力学数据,采用双亚晶格模型(Ba2+)P(O2–,Si O44–,Si O20)Q描述高温液相的Gibbs自由能,对Ba O–Si O2二元系相图进行了热力学优化与计算。计算获得了Ba2Si O4,Ba Si2O5,Ba Si O3,Ba2Si3O8,Ba3Si5O13,Ba3Si O5,Ba5Si8O21七个中间相的Gibbs自由能,这些数据很好地重现了实验相图值;在富Si O2端,获得了与实验数据更加吻合的液相线;计算的Si O2活度曲线与实验数据吻合良好,Ba O的活度曲线与实验值在Ba O的摩尔分数x(Ba O)为50%~80%范围时有差别,可能是实验误差所致;同时给出了液相混合Gibbs自由能。获得的自洽一致的相图与热力学数据可用于新型单相基质荧光粉及相关冶金体系的研究。
Ba O-Si O2 system is an important edge binary system of Ba O-Lu2O3-Si O2 ternary system. Based on the experimental phase diagrams and thermodynamic data, the Gibbs free energy of the liquid phase at high temperature is described by the double sublattice model (Ba2 +) P (O2-, Si O44-, Si O20) Q. The phase diagram of Ba O-Si O2 binary system Thermodynamic optimization and calculation were carried out. The Gibbs free energies of the seven mesophases of Ba2SiO4, BaSi2O5, BaSiO3, Ba2Si3O8, Ba3Si5O13, Ba3SiO5 and Ba5Si8O21 were calculated and obtained. These data well reproduce the experimental phase diagram values. At the Si02-rich side, The calculated curves of Si O2 activity agree well with the experimental data. The BaO activity curves and experimental values are in the range of 50% -80% of the Ba o molar fraction x (Ba O) There are differences in the range, which may be caused by experimental error. At the same time, Gibbs free energy of liquid phase mixing is given. The self-consistent phase and thermodynamic data obtained are useful for the study of novel single-phase matrix phosphors and related metallurgical systems.