THE RELATIONSHIP BETWEEN THE POROSITY AND ELASTIC-MODULI OF THE BI-PB-2212 HIGH-T-C SUPERCONDUCTOR

A series of Bi-Pb-2212 high-T-c superconductors, having different poro sities has been prepared by the solid-state reaction method. After the usual characterization of the samples by XRD, AC susceptibility, SEM, bulk-density and porosity studies, longitudinal (V-l) and shear (V-s) wave velocity measurements have also been undertaken by the pulse-tra nsmission technique. Using the experimental values of V-l and V-s, the Young's moduli (E) of all the samples have been calculated and are la ter corrected to zero porosity by employing a number of theoretical eq uations. The corrected moduli are compared with the literature value, which itself has been arrived at by averaging the available single-cry stalline stiffness constants. It is concluded from the results that am ong all the formulae, Mackenzie's equation and that proposed by the au thors of the present investigation are in closest agreement with the l iterature value.