We studied the chemical compatibility of Ag, Ag(In) alloy, Y2BaCuO5 (the so-called Y-211 green phase) and YBa2Cu3O7 d (Y-123) phase in order to check if better grain growth and alignment with minimum contamination were possible during the Y-123 melt texturing. We demonstrate that the addition of silver to Y-123 always led to an enhanced texture. The typical microstructure 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 addition 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-123 phase. We found a very unexpected thermal behaviour, similar to an eutectic equilibrium, when the silver concentration was increased to 35 wt%. We believe that this effect was essentially due to the increasingly higher concentration of silver that could react with the secondary phases present in the melt.

The influence of silver and Ag(In)alloy on Y-Ba-Cu-O equilibria around the Yb2Cu3O7-δ superconducting phase

COSTA, GIORGIO;FRANCESCHI, ENRICO;
2000-01-01

Abstract

We studied the chemical compatibility of Ag, Ag(In) alloy, Y2BaCuO5 (the so-called Y-211 green phase) and YBa2Cu3O7 d (Y-123) phase in order to check if better grain growth and alignment with minimum contamination were possible during the Y-123 melt texturing. We demonstrate that the addition of silver to Y-123 always led to an enhanced texture. The typical microstructure 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 addition 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-123 phase. We found a very unexpected thermal behaviour, similar to an eutectic equilibrium, when the silver concentration was increased to 35 wt%. We believe that this effect was essentially due to the increasingly higher concentration of silver that could react with the secondary phases present in the melt.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11567/189494
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