  The development of the PIT fabrication process of iron pnictide
superconducting wires and tapes has been carried out in order to enhance their
transport properties. Silver was found to be the best sheath material, since no
reaction layer was observed between the silver sheath and the superconducting
core. The grain connectivity of iron pnictide wires and tapes has been markedly
improved by employing Ag or Pb as dopants. At present, critical current
densities in excess of 3750 A/cm^2 (Ic = 37.5 A) at 4.2 K have been achieved on
Ag-sheathed SrKFeAs wires prepared with the above techniques, which is the
highest in iron-based wires and tapes so far. Moreover, Ag-sheathed Sm-1111
superconducting tapes were successfully prepared by PIT method at temperatures
as low as 900C, instead of commonly used temperatures of 1200C. These results
demonstrate the feasibility of producing superconducting pnictide composite
wires, even grain boundary properties require much more attention.
