Self-propagating high temperature synthesis of MgB2 superconductor in high-pressure of argon condition

Abstract

Magnesium diboride can be synthesized under argon ambient, elevated or high pressures. High-pressure syntheses are promising methods for manufacturing of the bulk MgB2 superconductor material. We have been used high pressure of Ar gas in order to investigate its effect on properties of MgB2 superconductor such as critical temperature and current density. Bulk MgB2 superconductor was synthesized from elemental Mg-B powders in thermal explosion mode of self-propagating hightemperature synthesis (SHS) under argon pressure of 25 atm. XRD pattern of the as-synthesized product indicates an almost complete conversion of the reactants to the MgB2 single phase. Most of the diffractions peaks are related to the MgB2 polycrystalline bulk material. The impurity fraction is less than 24.3% in total sample and identified as MgO and MgB4 secondary phases. The positive effect of pressure of Ar gas during synthesis of MgB2 on critical current density JC has been confirmed. The critical current density of the sample was achieved in high pressure reactor was 3.8X106 A/cm2. A superconducting volume fraction of 16% under a magnetic field of 10 Oe was obtained at 5 K, indicating that the superconductivity was bulk in nature. The succeeded level of superconductor parameters of the highpressure synthesized MgB2 and the possibility to produce a large bulk products make this technology very promising for practical applications.