Reaction between YBCO/Ag superconductor and melted silver

In order to study the feasibility of applying liquid phase processing using melted silver to fabricate YBCO/silver contacts, the chemical reaction at the boundaries between the Y-Ba-Cu-O (YBCO) superconducting matrix and melted silver was observed. YBCO superconducting current leads prepared by the unidirectional solidification method were dipped into liquid silver melted by an electric furnace. Copper-poor layers were formed at the boundary between the YBCO matrix and melted silver, although the temperatures were lower than the YBCO/Ag melting temperature (∼970 deg. C). It was considered that melted silver took up copper from the YBa2Cu3Ox (Y123) crystal, and it is considered that the phase equilibrium at the boundary between the YBCO matrix and molten silver was changed from Y2Ba1Cu1O5 (Y211)-Y123 to another phase. (author)