Abstract
MgB2 pellets containing a nanoscale dispersion of artificial pinning centres have been successfully manufactured through a powder metallurgy route based on the oxide dispersion strengthened (ODS) concept more usually used for steels and superalloys. Commercial MgB2 powder and Y2O3 nano-powder were mechanically alloyed in a high energy planetary ball mill and consolidated using the field assisted sintering technique. The composite powders were ball milled for different times up to 12 h and characterised by means of particle size analysis, x-ray diffraction (XRD) and scanning transmission electron microscopy (STEM). The microstructure and superconducting properties were characterised by density, XRD, STEM and magnetic property measurements. The powder microstructure comprised Y2O3 particles dissolved into the MgB2 matrix. After consolidation there was a near-uniform dispersion of precipitated YB4 and MgO particles. A bulk 0.5 wt% Y2O3-MgB2 composite showed the best superconducting performance with a significant improvement in J c at high field compared with unmodified MgB2, and only a small reduction in T c . The results suggest that the ODS concept is promising to improve the superconducting properties of MgB2.
Highlights
Since the discovery of its superconducting properties in 2001 [1] MgB2 has become a popular and promising material for superconductivity applications due to its interesting combination of properties
A bulk 0.5 wt% Y2O3-MgB2 composite showed the best superconducting performance with a significant improvement in Jc at high field compared with unmodified MgB2, and only a small reduction in Tc
This study investigates a new route to manufacture bulk MgB2 pellets of up to 20 mm diameter, containing a nanoscale dispersion of artificial pinning centres based on the oxide dispersion strengthened (ODS) concept more usually used in steels and superalloys
Summary
Since the discovery of its superconducting properties in 2001 [1] MgB2 has become a popular and promising material for superconductivity applications due to its interesting combination of properties. Most of these studies suggest that Jc improvements at high field is due to the presence of nanoscale pinning centres, most reports do not show any direct evidence of pinning centres and their characteristics; the decrease in Jc at low field is usually unexplained. The microstructure and superconducting properties of the bulks have been carefully characterised to provide a better understanding of the effect of the different microstructural features on Jc and Tc values
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
