单分散球形镍粉的制备与表征

采用液相化学还原法，以硫酸镍为原料、水合肼为还原剂、氢氧化钠为pH值调节剂制备了超细镍粉，并利用粉末X射线衍射、扫描电镜、热重和X射线光电子能谱对其进行了表征. 实验结果表明，所制粉末为面心立方(fcc)晶型、颗粒粒径范围约100~400 nm、纯度高、分散性好的球状镍粉，并获得优化工艺条件：Ni2+]=0.35 mol/L, NaOH]/Ni2+]=2.5, N2H4]/Ni2+]=4.0，反应温度80℃. 镍离子初始浓度决定产品二次颗粒大小，反应温度决定体系的反应速率，氢氧化钠和水合肼用量直接影响所得镍粉的还原率.

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.