Charge transfer resistance of nitro substituted dibenzalacetone on mild steel against acid attack

Corrosion of metals is a serious industrial problem due to its impact on economic losses and irresistible structural damage. In this work, dibenzalacetone derivatives 1, 5-bis (2-nitrophenyl)-1, 4- pentadien -3-one (BPDO) are employed as controlling agents on mild steel in 1 M H₂SO₄. The effect of BPDO on reducing corrosion of mild steel was analyzed using electrochemical and non-electrochemical methods. From experimental results, it is proved that the protection efficiency increases with enhance in BPDO concentration and diminishes with enlarge in temperature. BPDO is an effective corrosion inhibitor with a 98.64% inhibition efficiency at only 300 ppm concentration. IE diminishes as exposure time increases due to a decrease in the stability of the adsorbed BPDO on the metal surface. The results of Tafel polarization measurements revealed that BPDO acts as a mixed type inhibitor. In both the polarization and Electrochemical Impedance tests, 308K and 300 ppm of BPDO were used, yielding maximal inhibition efficiencies of 98.41% and 97.57% respectively. Langmuir adsorption isotherm is found to be the most suitable way to explain the adsorption of BPDO on the surface of mild steel. Physisorption is proposed from the values of ΔG_ads. Formation of a protective layer on mild steel surface was affirmed by various spectroscopic studies.