A study od parameters that influence growth and stability of the (Bi1-x Pbx)2 Sr2 Cu3 Oy phase

In this paper, the growth and stability of the (Bi1-xPbx)2Sr2Ca2Cu3Iy (Bi-2223) phase contained in silver-sheathed wires is investigated by a combination of x-ray diffraction, scanning electron microscopy, energy dispersive x-ray analysis, and transmission electron microscopy. Silver tubes loaded with Bi-2223 precursor powders were processed into filaments using established metallurgical techniques. The filaments were then heat-treated at selected temperatures (800 to 845 degrees C) for a range of times (10 to 6000 min) in a 7.5% oxygen atmosphere. From these studies it has been possible to investigate the time-temperature-oxygen pressure domains wherein Bi2Sr2CaCu2O8(Bi-2212) + second phases transform to Bi-2223