Fabrication of superconducting MgB2 from boron oxide (B 2O3), and its microstructural and electrical characterization

The discovery of superconducting MgB 2 (39 K) draws attention to it as a new material for applications based on superconductivity. Many researchers successfully synthesized MgB 2 using commercial boron and magnesium. In this study, elementary boron was obtained via an acid leaching process, after reacting B 2 O 3 , and Mg in an argon atmosphere at 800°C. Energy Dispersive X-ray Spectroscopy (EDX) results revealed that the powder obtained from the reaction was boron in 92% purity with magnesium as the major impurity. Superconducting MgB 2 was produced from this boron and magnesium, in an argon atmosphere at 900 °C, by a conventional solid-state reaction. Superconducting MgB 2 powders were compressed in a dye to pellets by a hot pressing technique at 500°C and 1 GPa. The microstructural properties of the MgB 2 were determined by X-ray Diffraction Spectroscopy, EDX, and Scanning Electron Microscopy techniques. The electrical properties of the fabricated MgB 2 were examined by resistivity measurements in a closed-cycle cryopump system, between 20 and 300 K. The critical temperature (T c ) of the MgB 2 pellets was around 32 K.