Studies of the phase evolution of YBCO materials with different additives

Abstract

Y123 samples with varying amounts of added Y211, and have been melt processed and quenched from temperatures between and . The microstructures of the quenched samples have been characterized using a combination of x-ray diffractometry, optical microscopy, scanning electron microscopy, microprobe analysis, energy-dispersive x-ray spectroscopy and wavelength-dispersive x-ray spectroscopy. The Ba-Cu-O-rich melt undergoes complex changes as a function of temperature and time. A region of stability of (BC1) and (BC2) exists below in samples of Y123 + 20 mol% Y211. is stabilized by rapid quenching but appears to separate into BC1 and BC2 at lower quenching rates. and additions affect the distribution and volume fractions of the two Ba-Cu-oxide phases.