Publications

This work reveals the influence of lead fluoride substitution and liquid nitrogen immersion on the mechanical properties of high-temperature superconductor samples (Cu0.5−xTl0.5Pbx)Ba2Ca2Cu3O10−δ−yFy, with (0.00 ≤ x ≤ 0.10). The samples under investigation were synthesized by solid-state reaction method at normal pressure. The samples were characterized using X-ray powder diffraction (XRD) and scanning electron microscope (SEM). The X-ray data have indicated that the partial replacement of Cu2+ ions by Pb2+ ions and oxygen by fluorine in the reservoir layer do not alter the tetragonal structure of the samples. On the other hand, the values of the lattice parameters a and c were found to be varied with x according to the difference in the ionic radii of Pb2+and Cu2+ as well as to the oxygen content. SEM analysis has revealed that lead fluoride substitutions improve the inter-grains connectivity of the prepared samples. The values of the superconducting transition temperature (Tc) were determined using ac magnetic susceptibility measurements. Vickers microhardness (Hv) was measured as a function of applied loads and the immersion time in liquid nitrogen (t). It was found that Hv values have recorded enhancements after one-hour immersion in liquid nitrogen. Moreover, the variation of Hv has shown an enhancement about 34% for x = 0.06. Furthermore, various models were employed to interpret the load dependence behavior of Hv.