MgB2/Fe wires have been produced by the powder-in-tube technique following the in situ route. The influence of low amounts of Cu or Ag additions into the precursor powder mixture on the kinetics of MgB2 formation was studied in situ by means of synchrotron x-ray diffraction during heat-treatments at 504 and 547 degrees C. Both Cu and Ag additions result in a significant increase of the MgB2 formation rate. A thin, discontinuous Fe2B layer was formed at the interface between the MgB2 core and the Fe sheath. At the end of the heat-treatment, Cu and Ag were found in submicrometer-sized particles segregated within the MgB2 matrix.
Grivel, J-C., Abrahamsen, A. B., & Bednarcik, J. (2008). Effects of Cu or Ag additions on the kinetics of MgB2 phase formation in Fe-sheated wires. Superconductor Science and Technology, 21(3), 035006-035010. https://doi.org/10.1088/0953-2048/21/3/035006