Examination of Y2Cu2O5 additions on microstructural development in YBa2Cu3O7 − δ superconductors

The role of Y2Cu2O5 on liquid phase flux and microstructure evolution were examined in two series of experiments. The first series of experiments dealt with a low temperature processing (< 1020 °C), while the second series involved the high temperature (> 1020 dgC) melt powder melt growth process (MPMG). Differential thermal analysis measurements were used to study the impact on liquidus formation reactions, solidification temperatures and kinetics. Microstructural evaluations via SEM, EDS along with TEM and microdiffraction techniques reveal some unique aspects of Y2Cu2O5 additions on the liquid phase matrix and microstructural refinement during processing. The yttrium enrichment of the Pt-Ba-Cu-O phase for MPMG samples was shown along with significant coalescence of such a phase not seen in similar samples with Y2Cu2O5. Extensive liquidus formation occurs allowing for texturing via diffusive couple oxide liquid phase intrusion below the peritecticecomposition.