Effect of ethylenediamine on the electrodeposition of Ni-Fe alloys

Ethylenediamine (EDA) greatly affects the phenomenon of anomalous codeposition observed in the nickel-iron electrodeposition system. EDA increases the Ni/Fe ratio of the deposit when the bath is chloride based and the pH is at least 5. Ion microprobe analysis indicates that EDA is incorporated in the deposit. It is hypothesized that EDA adsorbs on the deposit surface and serves as a bridge for Ni2+ deposition in preference to that for Fe2+, which forms less stable complexes with EDA. Chloride ion in the bath is necessary for the adsorption of EDA, and thus the relative increase in the nickel deposition rate. (C) 1999 The Electrochemical Society. S0013-4651(98)07-094-3. All rights reserved.