Characterization of Bi1.6Pb0.4Sr2Ca2Cu3Oy ceramic superconductor prepared via coprecipitation method at different sintering time
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The Bi(Pb)-2223 superconductor has been prepared via coprecipitation (COP) method from solutions of metal acetates and 2-propanol solution of oxalic acid at low temperature (0–2 °C). The metal oxalates powder was subjected to precalcination of 12 h at 730 °C, followed by 24 h calcination at 845 °C. The pelletized powder was sintered for 24, 48 and 100 h at 850 °C. The dominance of high-TC phase was observed for all samples as evidenced in the single step transition of (R–T) curves. The TC(R = 0) for samples sintered at 24, 48 and 100 h were 102, 102 and 104 K, respectively. XRD data showed the tetragonal structure for all samples followed by the enhancement of the 2223 phase as sintering time increased. Ac magnetic susceptibility measurements showed the improvement of the grain connectivity as sintering time increased. SEM micrographs showed large flaky grains of ∼7 μm in size and randomly distributed, which belong to 2223 phase. The degree of grains alignment increased as the sintering time increased.
KeywordsOxalic Acid Sinter Time Metal Acetate Magnetic Field Increase Ceramic Superconductor
The financial support of the IRPA Grant vote: 4-07-05-026 (High Temperature Superconductors) from the Ministry of Science, Technology and Innovation Malaysia is gratefully acknowledged. The authors would like to express their gratitude to electron microscopy unit at Institute of Biosciences (UPM) for rendering the facility of JEOL 6400 scanning electron microscopy (SEM).
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