Effect of saccharin on corrosion resistance of bright Ni coatings under conditions simulating a wet tropical climate

Abstract Corrosion behavior of bright nickel coatings, deposited from sulfate-chloride electrolytes with addition of saccharin and without it, has been studied. The addition of saccharin at a concentration of 5 g/l to a bright nickel-plating electrolyte causes an increase in the content of sulfur in the deposit structure up to 0.25 wt %. The corrosion rate of nickel deposits with the corresponding content of sulfur in acetic acid vapour and dilute acetic acid has been shown by 1-2 orders of magnitude greater than that of deposits containing 0.049 wt % of sulfur obtained from solutions without saccharin. This work suggests that the corrosion rate of nickel coatings is connected with the effect of the content of sulfur in the deposit structure on the adsorption of acetic acid on their surface. A synergetic effect of chloride ions on the corrosion of nickel deposits in the acetic medium has been established.