Preparation and Characterization of Mono-disperse Spherical Nickel Particles

Mono-disperse spherical nickel particles were synthesized by liquid phase reduction method with nickel sulfate as raw material,hydrazine as reductive agent,and sodium hydroxide as adjusting pH value of the solution.The prepared powder samples were characterized by means of X-ray diffraction(XRD),scanning electron microscopy(SEM),thermo-gravimetry(TG) and X-ray photoelectron spectroscopy(XPS).The results indicated that the high purity spherical particles had the face-centered cubic(fcc) crystal structure and their final diameters were between 100 and 400 nm with narrow size distribution.The optimal technological conditions were obtained as that the concentration of Ni2+ was 0.35 mol/L,the ratio [N2H4]/[Ni2+] 4.0,the ratio [NaOH]/[Ni2+] 2.5,and the reaction temperature 80℃.Moreover,the original concentration of nickel controlled the shape,size and agglomeration of the nickel particles,the temperature controlled the reaction rate,and the amounts of NaOH and hydrazine affected the purity of nickel powder.