WHISKER MATRIX INTERFACE AND MICROSTRUCTURE OF MGO-WHISKER REINFORCED(BI,PB)(2)SR2CA2CU3OX HIGH-TEMPERATURE SUPERCONDUCTING COMPOSITE/

In this paper, a comprehensive study of the microstructure and the whi sker/matrix interface of a (MgO)(w)/BPSCCO high-temperature supercondu cting composite is reported. The bulk MgO-whisker reinforced HTS BPSCC O (2223) composite was fabricated using a recently developed solid-sta te processing method. The (MgO)(w)/BPSCCO composite has been demonstra ted to possess excellent combined superconducting and mechanical prope rties. The favorable microstructure of the HTS BPSCCO (2223) matrix an d the (MgO)(w)/BPSCCO interfacial properties are recognized to be the critical material parameters governing electric and mechanical perform ance of the HTS composite. Effects of detailed microstructure variable s on superconducting properties of the composite are addressed, includ ing the aspect ratio and the orientation of MgO whiskers, structure, a nd texturing of the BPSCCO matrix phase, and the (MgO)(w)/BPSCCO inter facial microchemistry. The results obtained reveal unique characterist ics of the reinforcing MgO whiskers dispersion, distribution, and orie ntation in the HTS composites. The evolution of the microstructure and texture of the matrix BPSCCO grains has also been studied in the proc ess of repeated hot-pressing and annealing heat treatment. The thermod ynamic compatibility and microchemistry in the MgO whisker and BPSCCO interface are also examined.