  In this paper we have investigated the effects of sintering time and
temperature on the formation and critical current densities of Fe-clad MgB2
wires. MgB2 wires were fabricated using the powder-in-tube process and sintered
for different periods of time at predetermined temperatures. All the samples
were examined using XRD, SEM and magnetisation measurements. In contrast to the
common practice of sintering for several hours, the present results show that
there is no need for prolonged heat treatment in the fabrication of Fe-clad
MgB2 wires. A total time in the furnace of several minutes is more than enough
to form nearly pure MgB2 with high performance characteristics. The results
from Tc, Jc and Hirr show convincingly that the samples which were sintered for
3 minutes above 800 oC are as good as those sintered for longer times. In fact,
the Jc field performance for the most rapidly sintered sample is slightly
better than for all other samples. Jc of 4.5 times 10 ^5 A/cm2 in zero field
and above 10 ^5 A/cm2 in 2T at 15 K has been achieved for the best Fe-clad MgB2
wires. As a result of such a short sintering there is no need for using high
purity argon protection and it is possible to carry out the heat treatment in a
much less protective atmosphere or in air. These findings substantially
simplify the fabrication process, making it possible to have a continuous
process for fabrication and reducing the costs for large-scale production of
MgB2 wires.
