THE EFFECT OF PARTIALLY ORIENTED PRECURSORS ON THE MELT-TEXTURED GROWTH OF YBA2CU3O6+X

In order to accelerate the melt-textured growth technique, we introduce the use of partially oriented YBa2Cu3O6+x superconducting material as precursor for the melt-texture growth processing, instead of the randomly oriented precursors that are presently in use. We study the effect of this change of the starting material on the microstructure and the surface and bulk preferred orientation of the crystallites as a function of the peritectic solidification time, using scanning electron microscopy (SEM) and x-ray diffraction. The crystallites of these partially oriented precursors serve as ''seeds'' for the growth of large crystallites (approximately 300 mu on the average) in highly textured samples, whereas the cooling rate around the peritectic temperature is increased by a factor of 2.5 compared to other melt textured growth processes that are reported. While these studies are on small pellets or bars, they demonstrate a principle that can be incorporated in commercial processing.