Fast creation of dense MgB 2 phase in wires made by IMD process

Single-core MgB 2 wires have been made by internal magnesium diffusion (IMD) into boron process. Heat treatments were performed at variable periods (4–90 min) for two adjusted temperatures 635 °C and 650 °C, with an overshoot of ≈20 °C after 5 min. Critical currents of differently treated MgB 2 /Ti/GlidCop wires have been measured and related with the MgB 2 layers. The fast creation MgB 2 compound has been observed after 8 min annealing at both temperatures and showing the critical current maxima. The less uniform MgB 2 containing cracks was created for longer annealing periods (≥10 min), which resulted in lowered critical currents and worsened thermal stability. The fast creation of dense MgB 2 allows it to utilize a continual and short heat treatment process for high current density wires made by IMD.