Preparation of Ni-Co Alloy Foils by Electrodeposition

Electrodeposition of Ni-Co alloy foils on titanium substrate was performed in an acid chloride-sulphate bath. The influences of electrodeposition parameters such as current density, temperature, pH value, cobalt sulphate and saccharin concentration on composition and current efficiency were investigated in detail. The morphology and the microstructure of deposits were analyzed by SEM and XRD, respectively. The results indicated that the optimum parameters were current density 3 4 A/dm, pH 2 3, temperature 40 50 ̊C, cobalt sulphate 20 g/l and saccharin 2 3 g/l. Chemical analysis of the deposits by EDS revealed anomalous Ni-Co codeposition occured in this system. The SEM showed that hydroxide particles were not present on the surface and that fine-grain, smooth and compact Ni-Co alloy deposits were obtained. The crystallographic structures of Ni-Co alloy foils were the fcc Ni solid solution. The Ni-Co alloy foils with Co content 17.3 37.2 wt% and thickness of 20 45 μm were bright with low residual stress and super toughness.