BaB2O4低温相单晶体的生长及其相关体系相图的研究

本文用差热分析和X射线衍射等方法研究了BaO-Na₂O-B₂O₃三元系的两个截面:BaB₂O₄-Na₂B₂O₄和BaB₂O₄-Na₂O赝二元系的相平衡关系。BaB₂O₄-Na₂B₂O₄属共晶体系,其共晶温度为826±3℃。在BaB₂O₄-Na₂O体系中发现一个新化合物BaB₂O₄·Na₂O,该化合物在846±3℃同成分熔化。BaB₂O₄·Na₂O对BaB₂O₄和Na₂O均为共晶体系,其共晶温度分别为755±3℃和573±3℃。并根据所得的结果,分别以15mol％Na₂O和13mol％Na₂B₂O₄为助熔剂,用提拉法培养出2×4×6mm³和2×4×8mm³的低温相BaB₂O₄单晶体。 关键词：

THE CRYSTAL GROWTH OF BaB2O4 LOW TEMPERATURE PHASE AND THE STUDY OF PHASE DIAGRAMS OF RELATED SYSTEMS

The pseudo-binary systems BaB₂O₄-Na₂O and BaB₂O₄-Na₂B₂O₄ in the ternary system BaO-Na₂O-B₂O₃ have been studied by means of thermal analysis and X-ray diffraction. The system BaB₂O₄-Na₂B₂O₄ is a eutectic one and it's eutectic reaction occurs at 826 ±3℃. A new compound BaB₂O₄·Na₂O which melts congruently at 846 ± 3℃ has been discovered in the BaB₂O₄-Na₂O system. There exist eutectie horizontals from BaB₂O₄ to BaB₂O₄·Na₂ at 755 ±3℃ and from BaB₂O₄·Na₂O to Na₂O at 573 ± 3℃. According to the obtained phase diagrams of the mentioned binary systems, the single crystals of BaB₂O₄ low temperature phase with dimensions of 2×4×6 mm³ and 2×4×8 mm³ have been grown by the Czochralski method from the melt containing 15 mol% Na₂O or 13 mol% Na₂B₂O₄ as flux.