Preparation and Superconducting Properties of Nb3Sn by Mechanical Alloying

The Nb3Sn was successfully prepared by a fast and convenient method in which the mixture of the Nb, Sn, and Cu powder was mechanically alloyed followed by heat treatment. The morphology, crystal structure, and critical temperature were measured by SEM, XRD, and VSM. The results show that with increased milling time, the size of the powders becomes increasingly homogeneous and uniform. The addition of copper to the blended powder makes it easier to form the final Nb3Sn. With the increase of milling time, the particle size and crystallite size decreased, and the tin diffraction peaks disappeared when the milling time was more than 3 h. The effect of surfactants on the process of milling was studied. The phenomenon of adhering to the wall was relieved when even a small amount of stearic acid was introduced into the reactants. After the process of milling, the time needed for heat treatment was greatly reduced; it only needed a few hours at the maximum temperature stage. The critical temperature of the products is over 17 K after a heat treatment of only 1 h, which greatly reduces the time and cost of the heat treatment process, indicating that the as-prepared products have potential applications for preparing Nb3Sn superconducting materials.

Automated summary

Nb3Sn was successfully prepared by mechanical alloying and heat treatment. With the increase of milling time and the addition of copper powder, the powders become more homogeneous. The introduction of a small amount of stearic acid relieved the phenomenon of powder adhering to the wall and greatly reduced the time needed for heat treatment.