Electrical and microstructural properties of superconducting MgB2/Mg composites

MgB2/Mg composites were prepared to improve mechanical properties of brittle superconducting MgB2. MgB2 and Mg powders were mixed at different weight ratios and uniaxially pressed in a cylindrical dye at 0.5 GPa and at various temperatures for two hours to prepare MgB2/Mg composites. X-ray diffraction, SEM and EDX were used for phase identification and micro structural characterization. In addition to the main MgB2 and Mg phases, the microstructural studies have indicated the presence of a minor amounts of second phases, namely MgO and B-rich compounds. The surface morphology, grain size and porosity ratio of the samples prepared under various temperatures were also investigated. The resistivity measurements were performed in the range of room temperature to 15 K. The effect of excess Mg and secondary phases on critical temperature of MgB2/Mg composites were studied.