Kinetic and morphological investigation of CoFe alloy electrodeposition in the presence of organic additives

The use of organic additives is widespread in the manufacturing of thin films using electrodeposition. Common additives like saccharin (SAC) are used as leveling and brightening agents. In the present work, a comparative study of the influence of organic additives containing a similar saccharin molecular structure on CoFe alloy electrodeposition has been performed in order to obtain information about the kinetics of the cathodic process and the morphology of the deposits. The study was based on an electrochemical investigation using steady-state polarization measurements, coupled with scanning electron microscopy and X-ray dispersive analysis of the CoFe deposits. The composition, the current efficiency and the partial current densities of the CoFe alloy were determined in order to study the influence of SAC, phthalimide (PHTA) and another additive containing sulfur element: o-toluene sulfonamide (oTOL) on the CoFe deposition from sulfate and chloride electrolytes at pH 3. Experimental results indicate that saccharin influence strongly the electrode kinetic contrary to oTOL and PHTA. The morphology of the CoFe deposits depends on used organic additive. It was also noted that the presence of saccharin results in smoother, more compact and more leveled deposits as compared to PHTA or oTOL.