Characterisation of the partial melt processing of Bi-2212

Conference item

The melting behaviour of high phase purity, stoichiometric Bi-2212 powder on silver in air has been characterised using simultaneous thermal analysis (STA) and hot stage microscopy (HSM). Short Bi-2212/Ag tapes have been prepared via electrophoretic deposition and partial melt processing over a series of temperatures from 870 degrees C to 900 degrees C. The dependence of microstructure on the peak temperature has been investigated using scanning electron microscopy (SEM) and related to the STA and HSM data. The highest critical current densities of greater than 3000Acm(-2) at 77K are reproducibly obtained for tapes processed in the temperature window where partial melting has occurred and the number and size of secondary phases are minimised. The critical current drops significantly when the tapes are processed at higher temperatures. It is concluded that STA and HSM can be used to predict the narrow temperature region within which the optimum partial melt temperature exists and that optimum heat treatment parameters vary for different powders and tape production routes.

Authors: Morgan, C; Priestnall, M; Hyatt, N; Grovenor, C

• Publication status: Published
• Journal: APPLIED SUPERCONDUCTIVITY 1995, VOLS. 1 AND 2
• Volume: 148
• Pages: 331-334
• Publication date: 1995-01-01
• Event title: 2nd European Conference on Applied Superconductivity (EUCAS 1995)
• ISSN: 0951-3248
• ISBN: 0750303484
• Keywords: tapes