Premium
Influence of Ca 2 PbO 4 on Phase Formation and Electrical Properties of (Bi,Pb) 2 Sr 2 Ca 2 Cu 3 O 10 /Ag Superconducting Composites
Author(s) -
Guo Yuan Chang,
Liu Hua Kun,
Dou Shi Xue
Publication year - 2000
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.2000.tb01448.x
Subject(s) - sintering , materials science , microstructure , scanning electron microscope , composite number , phase (matter) , superconductivity , differential thermal analysis , composite material , diffraction , high temperature superconductivity , melting temperature , electrical resistivity and conductivity , chemistry , condensed matter physics , physics , electrical engineering , organic chemistry , engineering , optics
(Bi,Pb) 2 Sr 2 Ca 2 Cu 3 O 10 (Bi2223) precursor powders with large and small amounts of Ca 2 PbO 4 phase were prepared and used to make superconductor/silver composite tapes. The melting behavior of the powders and tapes was examined by differential thermal analysis (DTA). The influence of Ca 2 PbO 4 on the formation and microstructure of Bi2223, and electrical properties of the tapes, was investigated by X‐ray diffraction (XRD), scanning electron microscopy (SEM), and critical current measurements. It was found that the melting onset temperature ( T m,onset ) of precursor powders and composite tapes was strongly dependent on the amount of Ca 2 PbO 4 . Tapes with a small amount of Ca 2 PbO 4 had a higher T m,onset and a higher optimum sintering temperature compared with tapes with a large amount of Ca 2 PbO 4 . Also because of the higher sintering temperature, the total sintering time required for the former tapes was drastically shortened compared with the latter ones (250 vs 110 h). Furthermore, the microstructure and the current‐carrying capacity of the tapes were significantly improved by reducing the Ca 2 PbO 4 content of the precursor powders. These results are of practical significance for the commercialization of Bi‐based high‐temperature superconductors.