The effect of milling conditions on the magnetic and topological properties of MgB2 synthesized by high-energy ball mill and sintered at low temperature

Abstract

Magnesium diboride, MgB2, is known to be an important high-temperature superconductor material. High-energy ball milling with subsequent low-temperature sintering remains an attractive solid-state method for its synthesis. One main optimization parameter of this method is to ensure a balance between cold welding and fracturing at the milling stages. Therefore, in many cases, the use of a process control agent at the milling stage is considered to be the preferred solution in the prevention of particle size enlargement. The aim of this paper is to determine the effect of dry and toluene-assisted milling on the magnetic and surface topology properties of obtained MgB2. The calculated critical current density of 2.89 × 105 A/cm2 at 10 K 0.3 T for a toluene-assisted sample, compared with the 2.37 × 105 A/cm2 for a dry-milled sample as well as the relatively higher mean surface roughness, clearly indicated a notable positive contribution of surfactant use on the true alloying of MgB2 by mechanical activation.