Preparation of Core-Shell Structured Cobalt Coated Tungsten Carbide Composite Powders by Intermittent Electrodeposition

Core-shell structured cobalt coated tungsten carbide (WC/Co) composite powders were prepared by intermittent electrodeposition. The influence of process parameters such as current density, single deposition pulse, pH value and surfactants on the formation of WC/Co was investigated and characterized by scanning electron microscopy (SEM), electrochemical station, acidometer and X-ray diffraction (XRD) techniques. The composite powders with 54% cobalt content were fabricated at a current density of 16 A dm−2, with a load of 10 g dm−3 WC powders and a stirring speed of 600 r min−1 at an operation temperature of 40 ± 2 °C, and 90% current efficiency was obtained with a single deposition pulse of 1.5 min and single stirring pulse of 2 min during 12 min efficient electrodeposition time. The uniformly distributed WC/Co powders could be obtained in the cobalt electrolyte containing 300 mg dm−3 PEG-2000. The spherical cobalt grains coated WC particles were prepared in the pH 4−5 electrolyte at the Co deposition rate of 0.58 g min−1. A practical process for high efficient production of WC/Co powders by electrodeposition was developed in the present work.