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

T he 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 slopes increased 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. ‎