Study of the MgB2 grain size role in ex-situ multifilamentary wires with thin filaments

Abstract

The MgB2 superconductor has already demonstrated its applicative potential, in particular for DC applications such as MRI magnets, thanks to the low costs of the raw materials and to its simple production process. However further efforts have still to be made in order to broaden its employment also towards the AC applications such as SFCL, motors, transformers. The main issues are related to the reduction of the AC losses. Some of these can be faced by obtaining multifilamentary conductors with a large number of very fine filaments and, in this context, the powders granulometry can play a crucial role. We have prepared MgB2 starting powders with different granulometries and by the ex-situ P.I.T method we have realized multifilamentary wires with a number of filaments up to 361 and an average size of each filament lowered down to 30 microns. In particular we have studied the relationship between grain and filament size in terms of transport properties and show that the optimization of this ratio is possible in order to obtain suitable conductors for AC industrial applications.

References in corpus (3)

• Significantly enhanced critical current densities in MgB2 tapes made by a scaleable, nano-carbon addition route
• Prospects for Improving the Intrinsic and Extrinsic Properties of Magnesium Diboride Superconducting Strands
• Effect of grain refinement on enhancing critical current density and upper critical field in undoped MgB2 ex-situ tapes

Cited by in corpus (5)

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• Large critical current density improvement in Bi-2212 wires through groove-rolling process
• Grain size determination of superconducting MgB2 powders from magnetization curve, image analysis and surface area measurement
• High temperature heat treatment of B precursor and P.I.T. process optimization to increase Jc performances of MgB2-based conductor