Silver coating of spindle- and filament-type magnetic particles for conductive adhesive applications

Spindle-type hematite and magnetite particles and nickel filaments have been coated uniformly with silver by using chemical reduction. The effects of the reaction time and the concentration and nature of the reducing agent on the particle coatings were investigated at constant temperature. The reaction time had a pronounced effect on the nature of the coated surface layer. Coated and core particles were examined by scanning electron microscopy (SEM) and energy-dispersive X-ray analysis (EDAX). The electrical properties of the particles were also characterized. The conductivity of nickel filaments which can be oriented under a magnetic field for anisotropic electric conduction increased from 302 to 877 S/cm at 3.5 kPa pressure when coated with silver.