Enhancement of superconducting and mechanical properties in BSCCO with Pb additions

Bi2-xPbxSr2Ca2Cu3Oy superconductors with the nominal substitution parameter x = 0.0, 0.18, 0.22, 0.25, 0.3, 0.35 and 0.5 were prepared by the usual solid-state reaction. The superconducting and mechanical properties of these compounds have been investigated by measuring electrical resistivity, X-ray diffraction, surface morphology and microhardness. These measurements revealed that the superconducting transition temperature T-c(0) formation of high T-c-phase, Young's modulus, yield strength and microhardness increased gradually with a rise in Pb concentration. The maximum of all these parameters occurs for the compound with x = 0.3. This behaviour may be attributed to the fact that the intergranular links strengthen and these regions are made more homogeneous up to x = 0.3 and later there is a reduction. This reduction may be ascribed to weakening of the intergranular links. These results are explained on the basis of low and high-T-c phases and bulk hardness. (C) 2001 Elsevier Science Ltd. All rights reserved.