Effects of Sintering Temperature and SiC Contents on the Microstructure and Superconducting Properties of In-situ MgB2 Wires

We fabricated the in-situ MgB2 wires using the powder-in-tube method and investigated the effects of sintering temperature and SiC contents on the microstructure and superconducting properties. Pure MgB2 wires and 5, 10, 20 wt.% SiC doped MgB2 wires were sintered at 600-degrees C for 30 minutes in Ar atmosphere. We found that MgB2 phase was mostly formed at the sintering temperature of 700 degrees C and above, and the critical temperature (Tc) increased with increasing sintering temperature. For the MgB2 sintered at 850 degrees C, the highest critical current density (Jc) was obtained to be 3.7 X 105 A/cm2 at 5 K and 1.6 T by a magnetic properties measurement system (MPMS). The addition of SiC to the MgB2 wires changed microstructure and critical properties. SEM observation showed that the MgB2 core had considerable micro-cracks in undoped wire and the density of micro-cracks decreased with increasing SiC contents. The critical temperature decreased as the SiC contents increased, on the other hand, the critical current density of SiC doped MgB2 wires in high magnetic field was enhanced compared to that of undoped MgB2 wires.