All kinds of spherical ultrafine nickel powders, varied in mean particle size (0.1-5μm),were prepared by chemical reduction in aqueous solution. The pH effect on the production of nickel powder and the main factors o...All kinds of spherical ultrafine nickel powders, varied in mean particle size (0.1-5μm),were prepared by chemical reduction in aqueous solution. The pH effect on the production of nickel powder and the main factors of their morphological control were studied. The nickel powder with purity 98.5% was obtained in the Na2CO3-NaHCO3 buffer system at pH 9.2-11. The surface-rubbed stirring oar helped to the preparation of nickel particles. The mean particle size was decreased to subndcron range by using AgNo3 as nucleating agent. PVP was an efficient agent to regulate particle shape andreduce aggregation.展开更多
The main technical problems of nickel powder for multiplayer ceramic capacitors are particle size controlling, the agglomeration and tap density. Ultrafine nickel powders with submicron size and spherical shape were s...The main technical problems of nickel powder for multiplayer ceramic capacitors are particle size controlling, the agglomeration and tap density. Ultrafine nickel powders with submicron size and spherical shape were synthesized by the hydrazine reduction of nickel sulfate in ethanol-water solvent. The effects of reaction temperature, nucleator and flow rate of nickel sulfate solution on nickel powders properties were investigated. The nickel particles synthesized were characterized by SEM and TGA. The results show that the average particle size changes from 0.1 to 0.7 μm by adjusting reaction temperature (53- 73 ℃) and flow rate of nickel sulfate solution (50- 100 mL/min). Moreover, temperature below 60 ℃ and appropriate flow rate of nickel sulfate solution (85 mL/min) are in favor of obtaining particles with high tap density (>3.0 g/cm3). In addition, the introduction of nucleator is useful to obtaining particles with narrow size distribution.展开更多
The ultrafine nickel particles/polyaniline nanocomposite materials were synthesized in situ polymerization by two step series W/O inverse microemulsion systems. As the first step, the ultrafine nickel nanoparticles wh...The ultrafine nickel particles/polyaniline nanocomposite materials were synthesized in situ polymerization by two step series W/O inverse microemulsion systems. As the first step, the ultrafine nickel nanoparticles whose diameter is 10～30 nm were prepared by the W/O inverse microemulsion systems and by the reduction. As the second step, the monomer aniline salt (AnH +Cl -)entered into the polar waterpools where contained nickel nanoparticles and the ultrafine nickel particles/Polyaniline nanocomposite materials whose diameter is 50～100 nm had been obtained by in situ polymerization. These nanocomposite materials were measured to characterize and the micromorphology, microstructure and physical interaction of the both ultrafine nickel particles and polyanilines were studied by transmission electron microscopy (TEM), XRD, infraed spectrum (IR).展开更多
文摘All kinds of spherical ultrafine nickel powders, varied in mean particle size (0.1-5μm),were prepared by chemical reduction in aqueous solution. The pH effect on the production of nickel powder and the main factors of their morphological control were studied. The nickel powder with purity 98.5% was obtained in the Na2CO3-NaHCO3 buffer system at pH 9.2-11. The surface-rubbed stirring oar helped to the preparation of nickel particles. The mean particle size was decreased to subndcron range by using AgNo3 as nucleating agent. PVP was an efficient agent to regulate particle shape andreduce aggregation.
基金Project(50474047) supported by the National Natural Science Foundation of China
文摘The main technical problems of nickel powder for multiplayer ceramic capacitors are particle size controlling, the agglomeration and tap density. Ultrafine nickel powders with submicron size and spherical shape were synthesized by the hydrazine reduction of nickel sulfate in ethanol-water solvent. The effects of reaction temperature, nucleator and flow rate of nickel sulfate solution on nickel powders properties were investigated. The nickel particles synthesized were characterized by SEM and TGA. The results show that the average particle size changes from 0.1 to 0.7 μm by adjusting reaction temperature (53- 73 ℃) and flow rate of nickel sulfate solution (50- 100 mL/min). Moreover, temperature below 60 ℃ and appropriate flow rate of nickel sulfate solution (85 mL/min) are in favor of obtaining particles with high tap density (>3.0 g/cm3). In addition, the introduction of nucleator is useful to obtaining particles with narrow size distribution.
文摘The ultrafine nickel particles/polyaniline nanocomposite materials were synthesized in situ polymerization by two step series W/O inverse microemulsion systems. As the first step, the ultrafine nickel nanoparticles whose diameter is 10～30 nm were prepared by the W/O inverse microemulsion systems and by the reduction. As the second step, the monomer aniline salt (AnH +Cl -)entered into the polar waterpools where contained nickel nanoparticles and the ultrafine nickel particles/Polyaniline nanocomposite materials whose diameter is 50～100 nm had been obtained by in situ polymerization. These nanocomposite materials were measured to characterize and the micromorphology, microstructure and physical interaction of the both ultrafine nickel particles and polyanilines were studied by transmission electron microscopy (TEM), XRD, infraed spectrum (IR).
