Gas phase synthesis of Ni3Fe nanoparticles by magnesium reduction of metal chlorides

FeCl2(g) and NiCl2(g) were used for chemical vapor synthesis of Ni3Fe nanosized intermetallic particles with Mg(g) as the reducing agent. The simultaneous reduction of the chlorides was performed in a tubular furnace with argon as the carrier gas under different gas flow rates and temperatures. Thermodynamic analysis based on the measured evaporation rate of the reactants predicted the formation of Ni3Fe compound. FESEM micrographs, X‐ray diffraction and WDS analysis of the resulting compound identified formation of homogeneous spherical nanosized Ni3Fe compound with a relatively narrow particle size distribution and geometrical mean diameter ranging from 134 to 66 nm. Results showed that increasing the argon flow rate from 0.6 to 1.4 l/min significantly decreased the average particle size at all temperatures because of a reduction in residence time and reactant concentration. Increasing the synthesis temperature from 895 to 1020 °C reduced the average particle size probably because of higher nucleation rate.