Ga. Costa et al., The influence of Ag and Ag(In) alloy on Y-Ba-Cu-O equilibrium diagram around the Y-123 superconducting phase, J THERM ANA, 61(2), 2000, pp. 539-549
We studied the chemical compatibility of Ag, Ag(In) alloy, Y2BaCuO5 (the so
-called Y-211 green phase) and YBa2Cu3O7-delta (Y-123) phase in order to ch
eck if better grain growth and alignment with minimum contamination were po
ssible during the Y-123 melt texturing. We demonstrate that the addition of
silver to Y-123 always led to an enhanced texture. The typical microstruct
ure of the composite Y-123 plus Y-211 (that is believed essential for high
critical currents in these High Tc superconductors) was not disturbed by ad
dition of silver up to 7.5 wt%, while higher concentrations of metal led to
a degradation of the texture. DTA-TG analysis was used to investigate the
influence of Ag and Ag(In) alloy on the Y-Ba-Cu-O equilibria around the Y-1
23 phase. We found a very unexpected thermal behaviour, similar to an eutec
tic equilibrium, when the silver concentration was increased to 35 wt%. We
believe that this effect was essentially due to the increasingly higher con
centration of silver that could react with the secondary phases present in
the melt.