LAUSR

Abstract In this study, Co nanoparticles were mixed with WC powders by electroless plating with a new non-precious-Co-activation strategy. By soaking WC powders in a mixed solution of cobalt sulfate heptahydrate and sodium hypophosphite and then heat treated at 220 °C, Co active sites were seeded on WC powders to activate the following electroless plating of Co. The effects of reaction conditions on the weight gain and plating rate during electroless plating process were systematically investigated. As is evidenced by results, when the temperature, concentration of CoSO4 and NaH2PO2·H2O, and pH were 80 °C, 50 g/L, 45 g/L and 11 respectively, WC was evenly coated with Co. Notably, the XPS characterization indicated the content of zero-valence Co was elevated obviously after the plating process due to the effective reduction from two-valence Co.