Production of cobalt and nickel nanoparticles by hydrogen reduction

High mass concentrations of high-purity cobalt and nickel nanoparticles with primary particles diameter below 100 nm were produced with aerosol method. The size distribution of the primary particles was narrow. The particles were fcc single or twin crystal with little neck formation. The oxidation of the particles was slow, probably because there were few defects in the crystals structure and a thin protective hydrogen chloride layer. Chain-like agglomerates were formed likely because the particles were ferromagnetic. The process is promising for scaling up because it is a one-step process and temperatures are much lower than for cobalt evaporation techniques and no expensive precursor or additives are required.