Synthesis and characterization and pelletization pressure effect on the properties of Bi1.7Pb0.3Sr2W0.2 Ca2Cu3 O10+δ superconductor system

Abstract

The solid-state reactions technique is considered as one of the most important and useful methods adopted to prepare the superconductors ceramics samples. This method was used in the current work to prepare Bi1.7Pb0.3Sr2W0.2Ca2Cu3O10+δ samples, with different pelletization pressures ranged between 0.2 and 1.0 GPa sintered at 850 °C for 140 h. WO3 nanoparticles were added to the BSCCO system with 0.2% in order to improve the connectivity between the grain boundaries and then to increase the dc electrical resistivity and oxygen content. X-ray diffraction, SEM and Vickers microhardness measurements were adopted to characterize the samples. Considering the electrical, structural affected by high pelletization pressure. Both of the critical temperature TC and oxygen content δ were enhanced dramatically at different pressures, so they reach to the optimum values of 130 K and 0.224 respectively, at a pressure of 0.4 GPa. The orthorhombic crystal structure has been seen by the XRD analysis which presented both high Bi-(2223) and low Bi-(2212) phases that exist in the samples. SEM showed common microstructures and features of plates-like grains that were randomly distributed across all samples. On the other hand, the mechanical properties were noticed to be improved with increasing the pressure from 0.2 to 0.8 GPa. The microhardness, Young modulus and yield strength demonstrated a drop when the pressure was increased up to 1.0 GPa.