To determine mechanical properties of Ag doped Bi-2223 superconductors ceramics

In this study, the effect of silver substutition for copper on mechanical and superconducting properties of silver doped Bi-2223 have been investigated. The samples were prepared by substituting silver (0.00-0.12) for copper with changing ratios by solid state reaction method. The prepared samples were characterized using X-ray powder diffraction(XRD), Ac magnetic susceptiblity, scanning electron microscope (SEM), and microhardness measurements (Hv).X-ray diffraction (XRD) analysis suggests that the fraction of high-temperature phase decreases with silver substitution and after substituon of 0.03 the system shifted to the low-temperature phase. Scanning electron microscopy (SEM) examination reveals that both the number and size of the voids at the sample surface increase with Ag- doping rate. The critical temperatures were estimated from the temperature dependence of the ac susceptibility curves. We observed from the results that all the doped samples had a critical temperature in the range of 108-69 K.The Vickers hardness test applied to samples with five different load (0.294 2.942 N). The values of load dependent hardness increase with increasing Ag amount. Vickers microhardness, load independent hardness, Young's modulus, fracture toughness and yield strength values were calculated separately for doped and undoped samples. Experimental results of hardness measurements were analyzed using the Meyer's law, proportional sample resistance (PSR) model, modified proportional sample resistance (MPRS) model, Elastic-Plastic deformation model (EPD), and Hays-Kendall (HK) approach. Finally, the Hays-Kendall (HK) approach was determined as the most successful model describing the mechanical properties of our samples.Keywords: Ag substition, BSCCO, Vickers Microhardness