INFLUENCE OF EXCESS YTTRIUM ADDITIONS IN THE YBA2CU3O7-DELTA SYSTEM DURING MELT PROCESSING

Results are presented concerning the influence of excess yttrium addit ions on the microstructural development within YBa2Cu3O7-delta system. The melt powder melt growth process was the primary precursor system studied, with relevant experimental comparisons made to the phase pure YBa2Cu(3)O(7-delta) precursor system. Examination is made to quantita tively estimate the effects of yttrium additions on Y2BaCuO5 precipita tion during melt processing. Differential thermal analysis studies wer e performed to determine the effect of Y2O3 additions on liquidus form ation reactions and solidification temperatures. SEM and TEM analyses was used to evaluate microstructural effects of the Y2O3 additions. Hi gh temperature dynamic XRD was performed to analyze the effect of Y2O3 additions on phase development as a function temperature up to 1100 d egrees C.