The effect of saccharin addition and bath temperature on the grain size of nanocrystalline nickel coatings

Nanocrystalline nickel coating was synthesized by direct current electrodeposition from a Watts bath at the current density of 100 mA/cm2 and pH = 4. The effect of saccharin addition (0–10 g/l) and bath temperature (45–65 °C) on the average grain size of the deposits was investigated by XRD technique. The results showed that the average grain size decreased from 426 nm to 25 nm as the saccharin concentration increased from 0 to 3 g/l, while further increase in saccharin concentration had no significant effect. Theoretical model also indicated a non-linear function for dependence of grain size on saccharin concentration, which was in accordance with experimental results. The experimental results showed that the increases in the bath temperature had no considerable effect on the average grain size of the deposits. A theoretical formula was also established for the temperature dependence of the grain size.