Addition of nanometer Al2O3 during the final processing of (Bi,Pb)-2223 superconductors

Nanometer Al2O3 particles were added to (Bi,Pb)2Sr2Ca2Cu3Ox (Bi-2223) precursor powders during the final sintering cycle of a multi-step preparation process. The influence of Al2O3 on the melting temperature, high-Tc (Bi-2223) phase formation, microstructure and transport properties of ceramics was studied by means of DTA, XRD, SEM/EDX, electrical and magnetic measurements. We report that the addition of a small amount of Al2O3 (0.2 wt.%) increased the pellet's critical current density, Jc at 77 K by ∼30% and improved Jc behaviour in applied magnetic field either parallel or perpendicular to the sample wide surface (SWS). The results indicate that the introduction of a proper amount of nano-Al2O3 particles during the final processing of BPSCCO samples can effectively improve the flux pinning ability and has a little detrimental effect on the (Bi,Pb)-2223 formation process