Abstract
Effects of chloride ions in Watt’s type baths containing various amounts of chloride ions have been investigated by measuring the cathode current efficiency, cathode polarization, rest potential of the electrode, time-dependence of electrical double layer capacity, and stationary electrode polarogram.
The electrodeposition of nickel from higher concentration chloride baths occurs at more noble potentials with corresponding higher current efficiencies than from lower concentration chloride baths and a chloride ion-free bath. Thus, chloride ions in the bath facilitate the electrodeposition of nickel. Double layer capacity data show that specific adsorption of chloride ions occurs at the electrode surface. The pre-wave appeared in the stationary electrode polarogram when chloride ions were added to the chloride ion-free bath. This indicates that adsorbed chloride ions seem to electrocatalyse the nickel deposition by the same effect as that proposed by McCoy et al. in a mercury electrode.
