Electrodeposition of Ni-W-B amorphous alloys

Partial polarization curves at the glassy carbon rotating disc electrode have been used to study the electodeposition of Ni and Ni-W alloy from citrate-containing solution. For deposition of Ni-W alloys, the partial polarization curves indicate diffusion control for nickel reduction and stoichiometric limitation for tungsten deposition by the composition of the alloy. Plating experiments show that current efficency of the electrodeposition and composition of the resulting alloy depend on the parameters of the electrolysis. The best conditions for electrodeposition of the alloy Ni-W-B are current density of 45-50 mA cm exp -2 , temperature of 60-70 deg C, Ni(II) concentration of 20-25 mM, and pH 8.5. Pulsed galvenostatic plating at 1 Hz increased slighly the current effciency. The concentration of Ni(II) in the solution can be self-regulated by using a Ni bipolar electrode in the cathode compartment.