Effects influencing the grain connectivity in ex-situ MgB2 wires

Single-core MgB2/Fe ex-situ wires have been made by powder-in-tube (PIT) using: (i) commercial Alfa Aesar (AA) powder deformed by variable modes, (ii) AA powder oxidized by air milling and heat treatment and (iii) AA powder chemically treated by acetic and benzoic acid. All samples were finally annealed at 950 °C/0.5 h in Argon. The effect of deformation, oxidation and chemical treatment on the transport properties of MgB2 wires was tested. Differences in critical currents, transition temperatures and normal state resistivity are shown and discussed.