Phase assemblage in PBSSCOOPIT high-temperature superconductor precursor powders - Rietveld analvsis of x-ray diffractograms
Materialwissenschaft Und Werkstofftechnik 31(9): 829-832
The phase assemblage in PBSCCO-2223, (Bi, Pb)(2)Sr-2 Ca2Cu3O10 + x, precursor powders used for the production of long lengths of superconducting tapes by the oxide powder in tube (OPIT) technology has been determined by Rietveld analysis of powder x-ray diffractograms. The effects of grain alignment, structure modulation and anisotropic line broadening have been taken into account in the Rietveld analysis. The phase assemblage of the air-annealed precursor is typically Pb-free 2212 (Bi, Pb)(2)Sr2CaCu2O8 + x, Pb3Sr3Ca2CuO12, Ca2PbO4, Sr6Ca8Cu24O41, and Ca0.79Sr0.04CuO2. If the annealing is done in N-2, the Pb-41 phases disappear and Pb2+ enters the 2212 phase, which is accompanied mainly by Ca2CuO3 and CuO. Pb-2223 formation occurs above 830degreesC in air.