Carbon doping of precursor boron powder for control of normal resistance of MgB2 bulks for specific use in fault current limiter applications

11th European Conference on Applied Superconductivity

Archer, J.^1 ; Jarvis, A.L.L.^1

School of Engineering, University of KwaZulu-Natal, King George V Ave, KwaZulu-Natal, Durban

4014, South Africa^1

关键词: Boron precursor powders;    Bulk superconductors;    Chemical vapour deposition;    Critical temperatures;    Infiltration techniques;    Liquid magnesium;    Magnesium diborides;    Residual resistivity;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/507/1/012023/pdf
DOI  :  10.1088/1742-6596/507/1/012023

来源: IOP

【 摘 要 】

Magnesium Diboride (MgB2) bulk superconductor has been manufactured in order to study the enhancement of the normal resistivity for application to superconducting fault current limiters (SFCLs). SFCLs have proven to be a viable means for limiting surge currents by dissipating fault energy as the superconductor quenches. As the current limiting behaviour is determined by the normal resistivity (ρn), research has been conducted to evaluate an effective means to increase ρnfor bulk superconducting MgB2, which is intrinsically much lower than for high temperature superconductors. Intragranular carbon doping has been confirmed as a means to increase ρn, and was implemented by chemical vapour deposition (CVD) on the boron precursor powder by ethylene gas at 600°C for durations up to 6 hours in a tubular furnace apparatus. In situ manufacturing of MgB2bulk was performed using the reactive liquid magnesium infiltration technique. Overall, carbon doping provided a factor of 11.00 increase in the residual resistivity, ρ0, which provides the initial limiting action to fault currents, for an accompanying decrease in the critical temperature, Tc, of 2 K.