Improved<i>J</i>_c–<i>B</i>properties of MgB₂multifilamentary wires and tapes

Abstract

MgB2 multifilamentary wires and tapes were fabricated by the in situ powder-in-tube (PIT) process using acetone doped milled precursor powders. The critical current density of MgB2 is strongly enhanced by high energy milling and acetone doping. Furthermore, the liquid acetone can restrain the agglomeration of milled powder, which is beneficial to the fabrication of MgB2 multifilamentary wires. At 4.2 K and 10 T, the Jc of the 80 h doped Fe/Cu wire is 2.9 × 103 A cm−2, 20 times larger than that of the 1 h pure one (the '1 h' and '80 h', refer to ball milling times). The Jc of 80 h doped Fe/Monel tape is up to 9.2 × 103 A cm−2 at 4.2 K and 10 T. The Jc values of Nb barrier wires are comparable to those of the Fe barrier MgB2 wires. These results indicate that the addition of liquid C-containing material during high energy milling may be an effective way to get excellent properties of MgB2 for practical applications.