Substantial addition of PbO and liquid phase conversion during the final processing of (Bi,Pb)‐2223 thick film on Ag substrate and their influence on the microstructure and transport properties

Abstract (Bi,Pb)‐2223 polycrystalline samples were made by introducing into the precursor powders various weight fractions of PbO during the final sintering cycle of a multi‐step preparation process. The influence of PbO addition on the melting temperature, high‐T_C ((Bi,Pb)‐2223) phase formation, microstructure and transport property of samples was studied by DTA, XRD, SEM/EDX and electrical measurements. The results showed that the substantial addition of PbO up to 10 wt% promotes likely the stability and the abundance of the transient liquid phase during sintering, which in turn improved the grain growth an connectivity of (Bi,Pb)‐2223 phase, hence resulted in the improvement of transport current J_C. The ultimate value of critical current density at 77 K in the self‐field is found to be 1080 A/cm² in (Bi,Pb)‐2223 thick films on Ag substrate samples. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)