Nondestructive analysis of phase evolution and microstructure development in Ag/(Bi,Pb) 2Sr 2Ca 2Cu 3O x composite superconductor by 25 keV transmission X-ray diffraction

Abstract

X-ray diffraction (XRD) measurements were made on silver-sheathed (Bi,Pb) 2Sr 2Ca 2Cu 3O x (Ag/Bi-2223) composite superconductor using 25 keV X-rays produced by an insertion device beamline at a third generation synchrotron. These measurements, performed on fully sheathed multifilament-type Ag/Bi-2223 wire specimens, provided high resolution diffraction patterns that revealed (1) the phases present in the cores of the superconducting filaments and (2) the nature and quality of the Bi-2223 grain colony texture. In addition to the Bi-2223 phase, we were able to detect and to monitor specimen-to-specimen variations in the relative amounts of Bi-2212, Bi-2201, and the “3221” phase. The scattering geometry used (X-ray beam perpendicular to the Ag/Bi-2223 conductor rolling direction) resulted in the detection of several remarkably intense diffraction lines of Bi-2223, most notably the (2 0 0)/(0 2 0) pair, that were highly useful for recording pole figure maps evidencing the contiguous fiber texture microstructure of the Bi-2223 grain colonies. The nondestructive nature of the 25 keV transmission XRD method offers many advantages for the comprehensive study of phase evolution and microstructure development in Ag/Bi-2223 composite conductors.