The influence of starting YBa2Cu3O7-x particle size and Pt/Ce addition on the microstructure of YBa2Cu3O7-x-Y2BaCuO5 melt processed bulks

Y-Ba-Cu-O melt processed samples were prepared from mixtures of YBa2Cu3O7-x powders (starting average particle size ranging from 20 mu m to 400 mu m) with Y2O3 and 1 wt% CeO2 or 1 wt% PtO2. The resulting microstructure of the samples was composed of YBa(2)Cu3O(7-x)-Y-2 BaCuO5 network and Y2BaCuO5 low concentration regions with size and morphology correlating with the starting YBa2Cu3O7-x powder size independently of the holding time in the melted state. The 211 particle size was smaller for Ce doped samples than for Pt doped samples. The differences in porosity of Pt and Ce doped samples were related to the changes in the interfacial energy of the constituent phases.