Effects of metal powder addition on the critical current in MgB2 tapes

Effects of Metal (Ag, Sn and Zn) Nanoparticles Inserted into MgB₂ Grain Boundaries on Transport and Superconducting Properties

“…Tachikawa et al reported that adding Ag or Sn metals to MgB 2 powder improved connectivity between MgB 2 grains without annealing. 9,10) Moreover, they also reported that future improvement was observed by annealing at a moderate temperature of 473 K. These results ascribed that metal addition linked MgB 2 grains, thus improving connectivity. This method seems to be effective to the preparation of superconducting wires.…”

“…The maximum volume ratios of the metal were less than 6 vol%, which is half that used in previous studies. 9,10) Figure 1 shows the XRD patterns of each coated MgB 2 powder and that of bare MgB 2 powder for comparison. The XRD pattern of the bare MgB 2 powder indicates a hexagonal crystal structure with lattice constants of a = 0.3087 and c = 0.3523 nm, which conform to previously reported values.…”

“…As the result, the metal that is only utilized for grain linkage is expected to reduce the amount of metal required in previous reports. 9,10) Several techniques have been developed to coat powder particles with a metal layer.…”

“…Since soft metals are suitable, 9,10) Ag, Zn and Sn were selected as the coating metal. MgB 2 and Ag, Zn and Sn systems have been previously reported in several studies; however these studies focused on MgB 2 and metal alloys such as (Mg 1¹x A x )B 2 (A = Ag, 2129) Zn 3036) and Sn 3740) ).…”

“…There are rather a few studies on the superconducting properties of MgB 2 mixed with metals without alloying. 9,10) In this paper, using prepared MgB 2 powder coated with metallic Ag, Zn or Sn, the structural, transport and superconducting properties of composite MgB 2 /metal were evaluated. Moreover a portion of the composite MgB 2 /metal was annealed at a moderate temperature.…”