Effect of precursors on properties of nickel powders during chemical vapor deposition

To enhance the crystallinity and dispersibility of the nickel powders used in multilayer ceramic capacitors, the nickel powders were prepared by chemical vapor deposition. Taking nickel chloride powders as the precursors, the influence of nickel chloride with different particle sizes on the properties of nickel powders was discussed. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and laser particle size analyzer (LPSA), and the precursor mechanism on the formation of nickel powders was analyzed. The results show that the smaller precursor particles promote the adsorption of gaseous nickel chloride on the (111) crystal plane, inhibiting the growth and leading to the particle morphology transition from spherical to octahedral and cubic structures. In contrast, the larger precursors increase the vapor concentration, facilitate the formation of nickel powders with improved crystallinity and oxidation resistance, enhance the particle agglomeration, and reduce the dispersibility. When the particle size of the precursor is 82.5 μm, the nickel powders prepared show the best comprehensive performance with high sphericity, uniform particle size, good dispersibility, and at the same time, excellent crystallinity and oxidation resistance.