Effects of Pt doping on the size distribution and uniformity of Y2BaCuO5 particles in large-grain YBCO

Accurate and detailed image analysis of the Y2BaCuO5 (Y-211) particle distribution in large-grain Pt-doped and undoped YBa2Cu3O7-delta fabricated by seeded peritectic solidification has been performed using scanning electron microscopy. The size distribution of Y-211 particles along the a or b and c directions of doped and undoped grains has been measured and observed to approximate well to a log-normal distribution. The mean Y-211 particle size, which is independent of growth direction, is approximately 1 mu m and 1.5 mu m in the doped and undoped grains, respectively. The particle size distribution is significantly narrower for the Pt-containing material, however, corresponding to a much greater particle size uniformity. Such a uniform dispersion of fine Y-211 particles is desirable since it both enhances the critical current density of melt-processed YBCO and reduces liquid loss during peritectic solidification.