Structure and electrokinetic study of nickel electrodeposition

Electrodeposited layers of nickel show different growth characteristics depending on the composition of the electrolyte, namely the type of the anion, the presence or the absence of boric acid and the pH. These process parameters are examined in the present work in order to elucidate their influence upon the growth texture and the related surface morphology of the electrodeposits. The relationship between process and structure is investigated by studying the transient electrochemical behavior during deposition, in order to discriminate between different interface conditions corresponding to different growth modes. The observed preferred orientations can be in this way linked to different reactive species, which are assumed to be present at the surface, and to their stability. The correlation between kinetics and structure in nickel electrodeposition reported in the present work and the similar correlation found in cobalt electrodeposition suggest a rationalization of the growth modes of ECD inert metals, based on the correspondence between the transient Tafel parameter and the growth texture observed in defined conditions.