Study of BSCCO core density in multicore Ag sheathed tapes by microhardness profiles

Abstract

The effect of deformation by drawing, groove rolling and flat rolling on BSCCO core density in a seven-filament tape was studied by measurement of microhardness profiles (MHP). Ceramic core density and its homogeneity is monitored and compared in three characteristic filament positions after different stages of deformation. The transport current densities of sintered and press-sintered tapes deformed by 'drawing-flat rolling' and 'drawing-groove rolling-flat rolling' are compared and discussed in connection with the quality of the final filaments.

Critical current density and microstructure of iron sheathed multifilamentary Sr1−xKxFe2As2/Ag composite conductors

“…This result is similar to the flat rolled 7-filament BiSrCaCuO/Ag tapes, in which the filament closer to the sheath show higher average hardness, though the microhardness profiles across each individual filament are different [26]. In addition, we also measured the hardness for silver matrix and iron sheath for all the heat treated Sr-122/Ag/Fe conductors, and the results show no big difference for all the samples.…”

“…the lowest value of hardness (88 for 7-filament tape and 84 for 19-filament tape) was measured in the filaments in the center area of the tapes, and the filaments near the silver sheath have higher hardness up to 107 and 133 for 7-and 19-filament tapes, respectivly. This result is similar to the flat rolled 7-filament BiSrCaCuO/Ag tapes, in which the filament closer to the sheath show higher average hardness, though the microhardness profiles across each individual filament are different [26]. In addition, we also measured the hardness for silver matrix and iron sheath for all the heat treated Sr-122/Ag/Fe conductors, and the results show no big difference for all the samples.…”

“…However, for multifilamentary conductors with composite metal sheaths, we must consider more for J c performance due to their complex architecture and very small filament size. For BiSrCaCuO/Ag multifilamentary wires and tapes, microhardness were widely used to indicate the variations of mass density for filaments in different locations on transverse cross section, and provided a connection between deformation methods/parameters and J c distribution [25][26][27][28][29][30]. On the other hand, structural uniformity of BiSrCaCuO filaments along the longitudinal direction is also an important issue that must be taken into consideration.…”

Interface effects on the current transport properties of multi-layered (Ba, K)Fe2As2 superconducting wires

“…Groove rolling can be simply described as the deforming process acting in two perpendicular axes. 51 A diagrammatic sketch for the upper and lower groove rollers and the rolling gap between them, and the rolled wire in the center is given in both Fig. 7(a) and (b).…”

Mechanical processing of Ag/BSCCO high temperature superconductor tape

“…The individual filaments within an Ag/BSCCO multifilament tape produced by the OPIT method often have very different geometry and powder density, as shown among others by Husek et al [2]. Schuster et al [3] conclude that well textured, wide and thin centre filaments may have critical current densities 1 (J c ) about 11 times higher than narrow, 1 The critical current measure J c is the largest superconductive current possible I c (at 77 K, 0 T) divided by the cross-sectional area of the ceramic superconductor.…”