Texture relationships and interface structure in Ag-sheathed Bi(Pb)-Sr-Ca-Cu-O superconducting tapes

We have studied the phase composition, alignment, and bonding at the Ag/Bi-Sr-Ca-Cu-O (BSCCO) interface for silver-sheathed tapes of both the 2212 and 2223 compositions which have been processed under different conditions. Strong texturing of the (001) planes of the BSCCO phases parallel to the Ag interface was seen, regardless of the Ag orientation. Short facets of non-(001) BSCCO planes accommodate local misalignments between the Ag and the (001) planes of the BSCCO phases. Whether the 2212 composites are processed by complete melting or by sintering below the melting point, there is always a residual half-layer of 2201 at the interface. By contrast, 2223 composites exhibit 2223 layers right up to the interface without any transition phases. Both compounds bond strongly to Ag and cracks, when present, occur preferentially away from the interface.