Effect of sintering temperature and cooling rate on microstructure, phase formation, and critical current density of Ag-sheathed Bi{sub 1.8}Pb{sub 0.4}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} superconducting tapes
- Energy Technology Division, Argonne National Laboratory, Argonne, Illinois60439 (United States)
Silver-sheathed Bi{endash}Pb{endash}Sr{endash}Ca{endash}Cu{endash}O (2223) superconducting tapes (with a starting composition of Bi{sub 1.8}Pb{sub 0.4}Sr{sub 2}Ca{sub 1}Cu{sub 2}O{sub 8}, calcium cuprate, and CuO) were fabricated by the powder-in-tube technique. The tapes were sintered at various temperatures to optimize the formation of Bi{sub 1.8}Pb{sub 0.4}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10} phase within the tape. The results show that sintering within the temperature range of 815{endash}825{degree}C can produce tapes with high critical current density (J{sub c}). The J{sub c} of samples sintered at the higher temperature of 825{degree}C, where more liquid is present, depended markedly on the rate at which tapes were cooled from the sintering temperature; samples sintered at lower temperatures did not exhibit such a cooling-rate effect. The optimum combination of phase purity and microstructure that yielded an average transport J{sub c} of {ge}2.5{times}10{sup 4}A/cm{sup 2} was obtained when the tapes were sintered at 825{degree}C for 150 h and cooled at a rate of 25{degree}C/h from the sintering temperature. Quenching studies indicate that the Bi-2223 phase becomes unstable below 700{degree}C during slow cooling. This result may have important implications for processing Bi{endash}Sr{endash}Ca{endash}Cu{endash}O tapes with high J{sub c}. Addition of 15 vol.{percent} Ag flakes to the monolithic core exerted no significant effect on J{sub c}. {copyright} {ital 1998 Materials Research Society.}
- DOE Contract Number:
- W-31-109-ENG-38
- OSTI ID:
- 625834
- Journal Information:
- Journal of Materials Research, Vol. 13, Issue 2; Other Information: PBD: Feb 1998
- Country of Publication:
- United States
- Language:
- English
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