Growth of faceted 123 crystals in superconductive YBCO/Ag composites fabricated by infiltration-growth method

Growth process and structures of faceted 123 (YBa2Cu3O7−X) crystals fabricated by conventional unidirectional solidification and infiltration-growth method were studied experimentally and numerically to clarify the formation mechanism of the solidification structures of YBCO/Ag composites. Sample size was almost unchanged during the infiltration-growth process, since molten Ba–Cu–O with a small amount of Y and Ag was just infiltrated into pores in pre-sintered porous primary phase: 211 (Y2BaCuO5) with Ag and then it was cooled to grow 123 crystal. Solidified samples had uniform distribution of primary phase and Ag particles in peritectic 123 crystals. The critical transition condition of macrostructures from columnar to equiaxed structures, and the freezing front temperature of 123 crystal during solidification were clarified. The formation processes of macro/microstructure of faceted 123 crystals were simulated, and the results compared with the experimental ones.