Effect of fine boron powders prepared with a self-propagating high temperature synthesis on flux pinning properties of the MgB2/Fe composite wires

Fine boron powders were prepared by a self-propagating high temperature synthesis (SHS) based on the reduction of boron oxide by magnesium (3Mg + B2O3 → 3MgO + 2B). The synthesized boron powders with SHS process showed small particle size (∼350 nm) with highly enlarged surface area. The MgB2/Fe composite wire prepared with SHS-processed boron powders showed enhanced Jc properties under magnetic field. The major mechanism under this improvement was analyzed to be surface pinning by large number of grain boundaries owing to the small grain size of MgB2.