| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1507472 | Cryogenics | 2014 | 5 Pages |
•The higher precursor boron powder purity causes the formation of lower impurity phases.•Different purity of boron powder affects the transition temperature.•The purer and smaller boron precursor powder, which is produced from Turkish supplier, has the best Jc(H) and Tc performance.•Purified Turkish boron is a promising material to make MgB2 wires for industrial applications.
The superconducting properties of Fe sheathed MgB2 wire has been studied as a function of precursor B powder particle size. The in situ processed MgB2 samples were prepared by means of conventional solid state reaction method with magnesium powder (99.8%, 325 mesh) and three different types of amorphous boron powders (purity; 98.8%, >95% and 91.9%) from two sources, Pavezyum (Turkish supplier) and Sigma Aldrich. The particle sizes of Turkish boron precursor powder were selected between 300 and 800 nm. The structural and magnetic properties of the prepared samples were investigated by means of the X-ray powder diffraction (XRD) and ac susceptibility measurements. The XRD patterns showed that the diffraction peaks for our samples belong to the main phase of the MgB2 diffraction patterns. The highest critical temperature, Tc = 38.4 K was measured for the MgB2 sample which was fabricated by using the 98.8% B. The critical current density of this sample was extracted from the magnetization measurements and Jc = 5.4 × 105 A cm−2 at 5 K and B = 2 T. We found that the sample made by using the 98.8% boron showed almost 2 times higher Jc than that of obtained from 91.9% B powder.
