【摘要】 对YBa₂Cu₃O_7-x超导化合物在加热过程中的相转变进行了高压电镜原位观察,并做了在空气中的X射线衍射分析和真空处理样品的X射线衍射物相分析。结果表明,在真空环境下,相变温度与氧含量有关,一般比在空气中低100～120℃。在320～350℃,孪晶带开始消失,在样品表面出现一些Cu₂O黑斑,并开始由正交结构YBa₂Cu₃O_7-x向正交结构Y₂BaCuO₅化合物转变,在500℃左右相转变结束。在冷却过程中未发现相转变。更多还原

【Abstract】 In-situ HVEM observation on phase transition of the YBa₂Cu₃O_7-x superconducting compound in the process of heating was carried out, and high temperature X-ray diffraction analysis in air and X-ray diffraction phase analysis for the sample treated in vacuum condition were made.The results showed that the temperature of phase transition is related to oxygen content in the sample and in general, is 100℃ to 120℃ lower in vacuum condition than in air. At 320℃ to 350℃ twin bands begin to disappear, and some Cu₂O are formed on the surface of the sample and transit from orthorhombic YBa₂Cu₃O_7-x to orthorhombic Y₂BaCuO₅ compound. This transition was completed at about 500℃. Above 900℃, this compound consists of the Y₂BaCuO₅, BaCuO₂, Y₂O₃ and some other minor compounds. No phase transition was observed during cooling the sample.更多还原