Microstructural and mechanical characterization of bulk BSSCO (2223) superconductor

Bi1.84Pb0.34Sr1.91Ca2.03Cu3.06Ox bulk superconductor was prepared by hot pressing andpressureless sintering reaching relative density values in the 96-99 and 85-60% range, respectively. The hot-pressed specimensexhibited a textured microstructure with the c -axis preferentially aligned parallel to the direction of sintering pressureapplication, while the plastic flow into the particles, during hot pressing, favours the grain growth in the direction perpendicularto the pressure application. Both density and microstructure texturing results were greatly influenced by sintering temperatureand pressure. More specifically for pressureless sintered samples, high cold uniaxial pressure was first applied to prepare highlydense green bodies characterized by unusually high degree of texture orientation. They were subsequently pressureless sinteredto form links between grains by the activation of diffusion process and partial melting at the grain boundary. Mechanicalcharacterization, supported by microstructural evaluations, underline the anisotropic character of the material, its intrinsicbrittleness and low hardness.