Solidification Behavior and a Quasi-Ternary Phase Diagram of the YBCO/Ag System

Abstract

It is necessary to understand the solidification behavior because the mechanical properties and the thermal conductivity of the YBCO/Ag superconducting current leads prepared by unidirectional solidification method are influenced by the silver particle dispersion. Solidification behavior in the YBCO/Ag superconductor is discussed with the Y₂Ba₁Cu₁O₅-Ba₃Cu₅O_x-Ag (211-035-Ag) quasi-ternary phase diagrams, which were constructed by the analyzes of the solute compositions in the melt. The obtained phase diagram indicates that the solidification of the YBCO/Ag system proceeds through the monotecto-peritectic reaction, expressed as 211+BaO-CuO-rich melt (L₁)→Y₁Ba₂Cu₃O_y(123)+Liquid metallic silver (L₂). The diffusion fields in the YBCO/Ag system were discussed with using this phase diagram.