Up to now, the highest current densities of MgB₂ superconducting wires have been obtained by the internal magnesium diffusion (IMD) method. MgB₂ superconductors are especially suitable for DC or AC windings generating low or medium magnetic fields, where thermal stability and low AC losses are important issues. Mechanical, thermal and electrical parameters of the wires are strongly influenced by metallic materials used for the outer sheath. While highly electrical conductive sheath material is beneficial for thermally stable behaviour, it has a great effect on the generation of high eddy current losses. To minimize the contribution of eddy current losses, multi-core MgB₂ wires with low purity Cu and Al sheaths were prepared by the IMD process and characterized in detail. Results of low temperature measurements are analysed and discussed in the present work.

迄今为止，MgB ₂超导线材的最高电流密度是通过内部镁扩散（IMD）方法获得的。MgB ₂超导体特别适用于产生中低磁场的直流或交流绕组，其中热稳定性和低交流损耗是重要问题。电线的机械、热和电参数受用于外护套的金属材料的影响很大。虽然高导电性护套材料有利于热稳定行为，但它对高涡流损耗的产生有很大影响。为了最大限度地减少涡流损耗的贡献，多核 MgB ₂采用 IMD 工艺制备了低纯度铜和铝护套线并对其进行了详细表征。在目前的工作中分析和讨论了低温测量的结果。