In the present work, the effect of the complexing agents citrate, glycine and triethanolamine (TEA) on the electrodeposition of Ni-W layers from electrolytes based on NiSO4 and Na2WO4, is investigated. The investigations include measurement of the current efficiencies, determination of the tungsten content in the electrodeposits (by energy dispersive X-ray analysis), voltammetry studies and characterization of complex formation by UV-spectrometry. High W content and current efficiency could be realized by using electrolytes containing all of the three complexing agents. The results show that small amounts of glycine in a citrate-triethanolamine based electrolyte positively influences both the mass-transfer and the deposition potential.
Electrochimica Acta, 2005, Vol 51, Issue 5, p. 888-896