Akademik Veri Yönetim Sistemi
JOURNAL OF SUPERCONDUCTIVITY AND NOVEL MAGNETISM, cilt.23, sa.3, ss.397-410, 2010 (SCI-Expanded)
In this work, effects of compaction pressure on the structural and superconducting properties of BSCCO ceramic superconductors were investigated. The study was carried out on two systems which were, System I: Bi(1.7)Pb(0.3)Sr(2)Ca(2)Cu(3)O (y) and System II: Bi(1.6)Pb(0.3)Ag(0.1)Sr(2)Ca(2)Cu(3)O (y) , respectively. Ceramic powders were prepared by conventional solid-state reaction method and sintered at 850A degrees C after compaction at five different pressures in the 150-750 MPa range. Critical temperatures of samples were determined by resistivity-temperature determinations made by four-point probe method in liquid nitrogen conditions. XRD analysis was conducted by powder X-ray diffraction method. Morphology of the grains present in the samples were determined by using scanning electron microscope (SEM) photographs at 2 Kx and 2.5 Kx magnifications for System I and System II, respectively. Sintered densities of the superconducting ceramics were measured by Archimedes water displacement method and unit cell parameters were additionally obtained from XRD data. T (c) values for System I was determined to be in the 109-115 K with sample D having the highest T (c) of 115 K while T (c) varied in the 104-109 K range and sample B had the highest T (c) value of 109 K for System II. The transition width, which is a sign of the purity of the samples, was determined to be narrow for both systems. The data obtained from X-ray diffraction measurements have shown that 2223 high-T (c) phase was dominant in both systems. The determination of the optimum pellet compaction pressure for BSCCO ceramic superconductors was the main purpose of this work. The results of this work indicated that compaction at around 450 MPa improves the superconducting and structural properties of the BSCCO ceramic superconductors.