Effect of cold isostatic pressing on the transport current of filamentary MgB 2 wire made by the IMD process

This work describes the effect of cold isostatic pressing applied to as-drawn filamentary wires in a GlidCop and/or Cu sheath made by the internal magnesium diffusion process. Critical currents of as-drawn and isostatically pressed wires at high pressures up to 2.0 GPa followed by heat treatment at 640 °C for 40 min were measured. The obtained results show an improvement in boron powder density resulting in an increase of the critical current of MgB 2 layers. The engineering current density increases by 4–13 times after the high-pressure treatment, and is influenced by the density of the boron powder and by the mechanical strength of the outer sheath.