Effects of saccharin and pyridine derivatives on the electrocrystallization of nickel

Abstract

SUMMARYThe effects of saccharin and three kinds of pyridine derivatives [pyridine, 3-amino-pyridine and pyridinium-1-propane-3′-sulfonate (PPS)] on the surface morphology and crystal orientation of nickel electrodeposited from a Watts bath (1M NiSO4 + 0.2 M NiCl2 + 0.5 M H3BO3) have been studied by means of electrochemical methods, scanning electron microscopy, and measurement of X-ray diffraction patterns. Saccharin and three kinds of pyridine derivatives were adsorbed on the electrode and inhibited the reduction of nickel ion. The inhibitory effect on the reduction of nickel ion increased in the order 3-amino-pyridine, pyridine and PPS. Large-grained electrodeposits were obtained from the Watts bath in the absence of organic additives. Fine-grained, bright, compact and smooth nickel electrodeposits, which had a preferred orientation with a (111) plane parallel to the surface, were obtained from the Watts bath containing PPS, saccharin and EPB.