Synthesis and characterization of SiC and CNT doped MgB2 superconducting wire

Abstract

Silica nanoparticles and carbon nanotubes-doped magnesium diboride (MgB2) superconducting wires have been successfully prepared via powder-in-tube (PIT) method. In this work, pure MgB2 was doped using various dopants concentrations at 1 and 2 wt.% of each silica nanoparticles (SiC) and carbon nanotubes (CNT). The mix was sintered at 800°C for 3 hours before putting it in a 6 mm diameter stainless steel tube wire and drawn to get 3 mm diameter of stainless-steel wire. The materials were characterized using X-ray diffraction (XRD) for phase and structural analysis and scanning electron microscope (SEM) for surface morphology. Further, superconductivity characteristic of the wires was examined through a transition temperature using a cryogenic magnet. Structural characterization examined using Xray diffraction showed that no other impurities of other phases were detected. Microstructural investigation using electron microscope showed even distribution of the particles with inherent porosities. Measurement at cryogenic temperature showed that pure MgB2 and 2 wt.% CNT doped MgB2 showed superconductivity characteristic after being sintered whereas others showed unique resistivity behaviors. After deformation by drawing process to form wires, all of the samples showed a superconducting behavior, however, the presence of SiC and CNT decreased the critical temperature, Tc, of MgB2. Although the samples doped with CNT decrease the Tc, CNT doped samples showed higher Tc than that of MgB2/SiC wires.