Fabrication and characterization of MgB2/SS 316L superconducting wire with amorphous boron prepared by sintering and cold rolling

Abstract

Magnesium diboride (MgB₂) is proposed to be a highly efficient wire with zero resistivity. In this research, Mg powder and amorphous-boron sheathed with a stainless steel (SS) 316L tube and powder-in-tube (PIT) technique were used in order to create a cheaper and potential superconductor that could eventually replace the currently expensive price crystalline boron. Mixed powder was put into SS 316L tube and compacted to avoid oxidation while being sintered at a temperature of 800 °C for one hour, prior to cold rolling with various size reduction. X-ray diffraction (XRD), scanning electron microscopy (SEM), and cryogenic magnet characterization were used to evaluate the crystal structures, surface morphology, and resistivity versus temperature and SQUID measurement for all samples. The XRD analysis revealed that the majority of the MgB₂ phase was produced accompanied with a small quantity of MgO and Fe phases. The results of the SEM showed particle agglomeration in the sample’s morphology. It has been found that using the size reduction up to 60 % in the cold rolling step, the critical temperature (Tc) onset of the resulting MgB₂ was calculated to be 39.25 and 39.44 K, respectively. This results reveal that the fabrication of the superconducting wire can be realized using a more economic raw material and process.