Effect of sintering temperature on properties of MgB2 wire sheathed by low carbon steel tube

MgB2 wire was fabricated through the in situ powder-in-tube method in flowing argon by using low carbon steel (LCS) tube as sheath material. Effects of sintering temperature on the phase composition, microstructure features and critical current density (Jc) are investigated by using X-ray diffractometer, scanning electron microscopy with an energy dispersive spectrometer and the standard DC four-probe technique. The result indicates that the highest Jc values have been achieved in the sample sintered at 700 °C, while Jc decreases with increasing sintering temperature. It is found that microstructure features in all samples, e.g. the thickness of interface layer, the phase composition and the size of MgB2 grain are responsible for the difference of Jc values.