Facile Synthesis of Nb₃Sn Via a Hydrogen Reduction Process

A controllable and facile process for the preparation of Nb₃Sn intermetallic compound nanopowders using NbCl₅ and SnCl₂ vapors reduced by hydrogen has been developed. The vaporizing rates of the two chlorides are controlled by measuring their mass loss as a function of carrier gas (argon) flow rate at certain vaporization temperatures, respectively. X-ray diffraction (XRD) patterns indicate that hydrogenous Nb₃Sn products are obtained under the vaporizing rate of 0.155 g min⁻¹ for NbCl₅ and 0.036 g min⁻¹ for SnCl₂ with the hydrogen flow rate of 2100 ml min⁻¹ at 1273 K (1000 °C). Results of semi-quantitative analysis by X-ray fluorescence (XRF) demonstrate that the atomic ratio of Nb to Sn in the as-synthesized products is 3.48:1, and the content of (Nb + Sn) is taken up to 89.61 wt pct from the total weight of the products. The products can be purified by vacuum heat treatment. Images of transmission electron microscopy (TEM) show that the products are homogenous particles with a mean diameter of 31 nm. In addition, the reaction ratio of the chlorides and the powder yield are controllable by hydrogen flow rate.