Microstructure homogeneity study on Bi2223 multifilamentary tapes by micro-x-ray diffraction

Abstract

The phase content and grain alignment of individual filaments in Bi2223 multifilamentary tapes have been successfully analysed by means of a micro-x-ray diffraction system. According to the 2223 phase formation rate and texture, filaments can be divided into three groups. The filaments in the centre part of the tape have higher 2223 phase content and better texture due to their thinner, flatter shape. The filaments near the tape edges are poorer because of their low density and irregular shape. The strong variation in filament shape and density could be two of the most important factors that affect the homogeneity of 2223 phase conversion and texture quality. Using a more reactive powder, a harder sheath and making heat treatment under 7% oxygen, as well as using rectangular wire to start the rolling process, can all increase the filament uniformity and enhance the tape's Jc value.

Angular effects of transport critical currents in high-temperature superconductor tapes

“…However we notice a higher critical current value for the 55 filament tape which can be ascribed to the manufacturing process in spite of an equivalent cross section for both samples. During the process many parameters such as the reactivity of the powder, the sheath, the heat treatment etc can have a considerable effect on the transport properties [23].…”

Effects of conductor anisotropy on the design of Bi Sr Ca Cu O sections of 25 T solenoids

“…Location of B r,max 2.17 18.7 18.83 6.6 Location of B z,max 0 24.02 24.02 0.0 distribution of grain misalignment angles around zero (as observed by x-ray diffraction [16]), the presented scaling function based on a Gaussian grain misalignment distribution will accurately reflect the angular dependence of I c , even if the distribution function is not Gaussian.…”