Reaction mechanism and microstructure of PAIR (per-annealing and intermediate rolling) processed Bi/sub 2/Sr/sub 2/CaCu/sub 2/O/sub x//Ag tapes

The effects of the PAIR process on the chemical reaction during partial melting and solidification were analyzed. There was no significant difference in the partial melting behavior detected by thermal analysis between PAIR processed and control samples. However, the HT-XRD and SEM analyses indicated that, in the samples processed by the PAIR technique, the (CaSr)CuO/sub 2/ crystals did not grow at the surface of the liquid phase but segregated as small particles in the well aligned superconducting layers. This can be explained by the high packing density in the PAIR processed tapes, which resulted in the formation of a uniform liquid phase and ideal solidification.