【摘要】 <正> 一、引 言 最近证实,在Y—Ba—Cu—O体系中,与超导性相关的相为Ba₂YCu₃O_7-δ。X射线衍射表明在650℃附近存在四方到正交的相变。中子衍射显示这个转变在δ=0.5时发生,转变温度与外界环境气氛有关。而氧含量对超导电性起着重要作用。因此,研究氧含量和其扩散动力过程,对于从理论上深入研究超导性的机制或从工艺上提高其超异性无疑都有着重要意义。更多还原

【Abstract】 By the use of isothermal dilatation measurement, the change in volume during isothermal holding between 300℃ to 500℃ for quenched Ba₂YCu₃O_7-δ superconductor with tetragonal structure is studied. Experimental results show that the transition process from tetragonal to orthorhombic structure, which is associated with the oxygen content in crystal is controlled by oxygen diffusion, and its activation energy is about 74015 J/mol.It is suggested that if powder particle size of specimen is 20μm in diameter,diffusion coefficient D can be expressed as:D=3.47×10^-6exp[-74015（J/mol）/RT]（cm²/s）.更多还原