Abstract
The effect of low-melting-point metal powder addition on the transport current and stress-strain performance of ex-situ processed MgB2 tapes with a Ni sheath has been studied. The addition of low-melting-point metal powders, such as In and Sn, produces an appreciable increase in the Jc of the MgB2 core. The addition of 10vol% In enhances Jc by a factor of 6-7 after the combination of rolling and annealing at 200°C. The Jc of the core with In addition is on the order of 105 A/cm2 at 0.5 T and 4.2 K. The addition of 10vol% Sn enhances Jc by a factor of ∼3. The In and Sn additions also appreciably increase the n value of the Ic transition. Both In and Sn metals impregnate into gaps among MgB2 grains, improving the linkage of the grains. The current can then transfer through the impregnated metal by the proximity effect. Furthermore, the addition of In and Sn offers an appreciable improvement in the strain tolerance of the MgB2 tapes. The addition of low-melting-point metal powders is a relatively simple and easy approach to yield better transport and stress/strain performance in ex-situ MgB2 tapes.
