Effect of Electroplating Parameters on Microstructure of Nanocrystalline Nickel Coatings

In order to achieve the optimum conditions for electroplating nanocrystalline nickel coating from Watts-type bath, the effect of some process parameters namely, bath temperature, current density, and saccharin addition on grain size and texture coefficient (TC= I(200)/I(111)) of the deposits were investigated by X-ray diffraction (XRD). The results showed that in a bath containing 5 g/L saccharin, by increasing the bath temperature from 45°C to 55°C, the grain size decreased, whereas further increase of bath temperature resulted in a contrary effect. By increasing the current density from 10 to 75 mA/cm2, both the grain size and TC decreased, while further increase in current density had no significant effect on the grain size. At a given current density, the grain size and TC decreased rapidly by increasing the saccharin content before leveling off at 3 g/L of saccharin. Finally, based on the grain refining the optimum conditions for producing nanocrystalline nickel coating from Watts-type bath have been proposed.