Preparation of dense bulk high Tc superconducting materials using hot isostatic pressing

Sintered superconducting materials were encapsulated in evacuated stainless-steel or pyrex glass containers and processed in a hot isostatic pressing (HIP) unit at high temperatures and pressures. Optimum HIP conditions to obtain bulk samples of nearly theoretical density were determined. Results indicate that in addition to density, HIP also improved T_c. For the one-two-three system, the grain size is significantly reduced during HIP. This is attributed to fracturing of coarse particles in the sintered compact due to high strain rates experienced during the pressurization. HIP materials can be machined to any shape and size, and the process being used for making specimens for J_c measurements and superconducting devices