Effect of SiO2 and SiC doping on the powder-in-tube processed MgB2 tapes

Abstract

Effect of SiO2 and SiC nano-powder doping was investigated for the powder-in-tube processed MgB2/Fe tapes. Mg or MgH2 powder was used as the Mg source of starting materials, and heat treatment was carried out at 600 °C for 1 h. These heat treatment conditions of lower temperature and shorter heating time are advantageous from the aspect of practical production processes. MgH2 powder improved the connection of MgB2 grains and prevented oxidation of MgB2. SiC and SiO2 doping greatly enhanced the critical current density (JC) values of the tapes prepared with Mg + B powder. However, only the SiC doping was effective in enhancing JC values for MgH2 + B powder. SiC doping decreased magnetic field sensitivity of JC, while SiO2 doping did not change the field dependence of JC. The SiC doped tape showed transport JC value of about 6 500 A cm−2 at 4.2 K and in the magnetic field of 12 T. The irreversibility field increased from 17 T to 23 T by the SiC doping.