Preparation and pattern recognition of metallic Ni ultrafine powders by electroless plating

Using hydrazine hydrate as reductant, metallic Ni ultrafine powders were prepared from NiSO4 aqueous solution by electroless plating method. The factors including concentration of NiSO4, bathing temperature, ratio of hydrazine hydrate to NiSO4, the pH of the solution, etc., on influence of the yield and average particle size of metallic Ni ultrafine powders were studied in detail. X-ray powders diffraction patterns show that the nickel powders are cubic crystallite. The average crystalline size of the ultrafine nickel powders is about 30 nm. The dielectric and magnetic loss of ultrafine Ni powders-paraffin wax composites were measured by the rectangle waveguide method in the range 8.2-12.4 GHz. The factors for Ni ultrafine powders preparation are optimized by computer pattern recognition program based on principal component analysis, the optimum factors regions with higher yield of metallic Ni ultrafine powders are indicated by this way. (c) 2005 Elsevier B.V. All rights reserved.