SYNTHESIS OF BULK NANOCRYSTALLINE NICKEL BY PULSED ELECTRODEPOSITION

Square-wave cathodic current modulation was used to produce nanocrysta lline nickel electrodeposits with grain sizes in the range 40-10 nm fr om saccharin-containing Watts-type baths. The optimum plating conditio ns to synthesize nanocrystals, namely pulse on- and off-time and peak current density, as well as bath pH and temperature, were identified. At these plating conditions, the grain size of the electrodeposits was found to decrease with increasing saccharin concentration in the bath . The preferred orientation of the deposits progressively changed from a strong (200) fibre texture for a saccharin-free bath to a (111) (20 0) double fibre texture for a bath containing 10 gl(-1) saccharin. Tra nsmission electron microscopy showed that the electrodeposits consist of uniform structure with narrow grain-size distribution. These deposi ts, as expected, were found to contain co-deposited sulphur and carbon impurities.