Current densities of MgB2 wires by combined ex situ/in situ process

SiC doped MgB2/Ti/Cu wires have been made by powder-in-tube technique using precursor prepared by mixing of MgB2 (ex situ) with Mg, B (in situ) in variable ex situ/in situ ratio. Wires containing 0%, 23%, 50%, 70%, and 100% of MgB2 powder were two axially rolled to 1.2 mm and annealed in Ar at temperatures 700–850 °C/0.5 h. Increased critical current density [Jc(μ0H) performance] has been measured for 23% and 50% of added MgB2, which is attributed to improved grain connectivity combined with more effective grain boundaries acting as pinning centers. This novel process utilizes the advantages of both techniques: lower MgB2 porosity typical ex situ and better grain connectivity and effective C-substitution through SiC addition obtained by in situ.