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).