Synthesis of Nickel Powders by Hydrazine Hydrate Reduction of Nickel Hydroxide

Abstract:

Fine nickel powders with a narrow particle size distribution were prepared by reducing nickel hydroxide in aqueous solution. The formation and reduction pathways of nickel powder were analyzed, as well as the effects of the molar ratio of hydrazine hydrate to nickel hydroxide, hydrazine concentration, and the dosage of surfactant PEG6000 on particle size, surface morphology, and dispersion. Results reveal that the nickel particle nucleation occurs on the nickel hydroxide surface, and the nickel hydroxide gradually dissolves during the reaction. With the increase in molar ratio of hydrazine hydrate to nickel hydroxide, the nickel particle size is initially decreased and then increased. Higher hydrazine hydrate concentrations result in smaller particle sizes. A small amount of PEG6000 surfactant can improve dispersion of nickel particles, but a higher amount of PEG6000 surfactant results in the maintenance of the morphology of nickel hydroxide. Adjusting the surfactant dosage can control the average particle size between 1–2 μm.