Enhancement of throwing power and covering power by applying composite additives in nickel sulfamate bath

The performance of the nickel sulfamate bath is enhanced as a result of the composite additives. The results show that the dispersion capacity is increased from 21.43% to 58.29% and the covering power is increased from 40.0% to 53.5% with the additives of dibenzenesulfonimide (BBI) 0.45~0.60 g/L, sodium allylsulfonate (SAS) 1.30~1.50 g/L, propynesulfonic acid sodium salt (PS) 0.08~0.10 g/L, hydroxy propyl-2-mercapto-disultfonic acid sodium (SSO3) 0.02~0.03 g/L, 1-(3-sulfopropyl)pyridine inner salt (PPS-OH) 0.08~0.10 g/L. All these additives, namely BBI, SAS, PS, SSO3 and PPS-OH in a nickel sulfamate bath have contribution to different degrees to both the throwing power and the covering power, which is the synergistic effect of the combined additives.