Bi_2O_3-SiO_2系统相图的研究

Study on Phase Diagram of Bi_2O_3-SiO_2 System

本文通过DTA和XRD研究了Bi2O3－SiO2二元系稳定相平衡和亚稳定相平衡，并绘制了该系统完整的相图，发现在稳定相图富SiO2一侧存在包晶反应L＋SiO2Bi4Si3O12，包晶等温线大约在1030℃，Bi4Si3O12确定为近一致熔融化合物，并且用淬火微结构的方法确定了包晶反应的液相线．在Bi2O3－SiO2系统的亚稳定相平衡中研究了它的析晶行为，亚稳定相Bi2SiO5冷却时在845℃左右析晶．

Stable and metastable phase equilibria in a binary Bi2O3-SiO2 system were studied and acomplete phase diagram of the system was proposed with DTA and XRD. A peritectic reaction L+Sio2 Bi4Si3O12 at the SiO2-rich side of stable phase diagram was identified to have peritectictemperature at about 1030℃ and peritectic point close to the end of the peritectic isotherm.Bi4Si3O12 was observed to be a nearly congruently melting compound and liquidus of the peritecticreaction was identified by quenching microstructure method. Crystallization behavior of Bi2O3Sio2 system was also investigated. The results show that metastable Bi2SiO5 crystallizes out at845℃.