Electrochemical deposition of nickel and nickel-thallium composite oxides films from EDTA alkaline solutions

An anodic electrodeposition procedure of nickel hydroxide and oxyhydroxide species using an alkaline bath containing 5 mM Ni2+ and 5 mM ethylenediaminotetraacetic acid as a ligand compound is described. The positive effect of thallium oxides and Tl+ on the rate of nickel deposition was estimated. In the presence of thallium species, the electrodeposition process of nickel oxide species is located at lower positive potentials of about 100-150 mV. The XPS analysis of nickel-thallium composite films, revealed the presence of Tl2O3. Tl2O, Ni(OH)2 and NiOOH, with an average composition independent of the specific electrochemical deposition procedure (i.e., potentiostatic, potentiodynamic or galvanostatic techniques).