Acetylacetonate Complexes as New Corrosion Inhibitors in Phosphoric Acid Media: Inhibition and Synergism Study

The corrosion inhibition performance of acetylacetonate complexes of zinc(II), manganese(II), cobalt(II) and copper(II) on the mild steel substrate in 1M H3PO4 was studied using DC polarization. It was seen that the mentioned complexes decreased corrosion rate of mild steel in phosphoric acid media due to the adsorption on metal surface. The potential of mild steel shifted toward more active potentials. The cathodic Tafel slopesincreased showing that acetylacetonate complexes are cathodic inhibitors. Presence of chloride ions in the electrolyte enhanced inhibition performance of acetylacetonate complexes due to synergism. Chloride ions provided by HCl had a better performance compared to NaCl. Prog. Color Colorants Coat. 2(2009), Institute for Color Science and Technology.