Preparation of submicron nickel powders by microwave-assisted hydrothermal method

Submicron nickel powders have been synthesized successfully from aqueous NiCl2 at various temperatures with ethanol–water solvent by using the conventional and microwave hydrothermal method. The reductive condition was prepared by the dissolution of hydrazine hydrate into basic solution. The samples synthesized in various conditions were characterized by the means of an X-ray diffractometry (XRD), a scanning electron microscopy (SEM), a thermo-gravimetry (TG) and an X-ray photoelectron spectroscopy (XPS). The samples obtained by using the microwave hydrothermal method were more smoothly spherical in shape, narrower in particle size distribution, and highly reduced on the surface area of particles, compared to the conventional one. Therefore, it was assumed that microwaves affected strongly the nucleation and crystal growth in the reduction step during the hydrothermal reaction.