The Effect of Cyclic Lactams and Their Structural Analogs on the Surface Morphology, Coating Properties, and Electroreduction Kinetics of Cu(II) Ions

The behavior of cyclic compounds in copper-plating sulfate electrolytes is directly determined by their structure (the nature of a heteroatom in a ring, the size of the cycle, and the presence of side carbonyl groups). The efficiency coefficient increases with an increase in the volume concentration of an additive in the presence of nitrogen-containing heterocycles, whereas that of oxygen-containing ones slightly depends on cL0. Calculation of the kinetic parameters of the process confirmed that kinetics of a cathode reaction is mainly due to the nature of a heteroatom in the cycle. Combined analysis of chronopotentiometry and impedance data showed that the complexes formed in the surface layer block the electrode surface, increase the Ψ′ potential, and make the discharge of metal ions difficult, with their inhibitory effect increasing with an increase in ligand concentration. Effective control of deposition rate, morphology, and properties of coatings is possible as a result of changes in the nature, structure, and volume concentration of the additives.