Effect of average current density on micromorphology and properties of pulse-electroplated Ni-W alloy coating

The effect of average current density on the appearance,adhesion strength,microhardness,deposition rate,tungsten content and surface morphology of pulseelectroplated Ni-W alloy coating was studied under the conditions of NiSO4 15 g/L,Na2WO4 30 g/L,citric acid 35 g/L,organic alkyl additive 1.5 g/L,pH 7 and temperature 65 °C. The results showed that the content of W is increased with increasing average current density while the hardness is increased initially and then levels off. Defects will be formed at very low or high average current density. The optimal average current density was found to be 5-8 A/dm2.