The influence of some 4-methylcoumarins on the electrodeposition and characteristics of zinc coating

摘要

This work presents investigation of the influence of some 4-methylcoumarins on the physicochemical characteristics of zinc coatings such as porosity, thickness, and resistance to corrosion. Six 4-methylcoumarins have been added to zinc solutions in different concentrations, and layer resistance to corrosion in 3% NaCl was evaluated by potentiodynamic methods. Thermodynamic and kinetic properties of zinc coatings as well as the stability of the passive layer coatings were determined at high anodic polarization. The interaction between coumarins and zinc has been investigated by IR spectroscopy. The corrosion resistance of zinc deposits was improved by use of coumarins as additives, especially the 7-hydroxy-4-methylcoumarin.