Experimental and DFT studies of a novel salicylhydrazone derivative as a steel corrosion inhibitor

The inhibitory properties of a newly synthesized salicylhydrazone derivative, namely 2-hydroxybenzaldehyde {(1E)-[4-(dimethylamino)phenyl]methylene}hydrazine (HBMH), towards the corrosion of XC38 carbon steel in 1 M hydrochloric acid, has been studied using weight loss, electrochemical measurements and theoretical calculations. Gravimetric results have shown that the inhibition efficiency of this compound increases with its concentration and decreases with temperature to reach a maximum of 90% at 293 K in the presence of 10−3 M of this inhibitor. Potentiodynamic polarization measurements have revealed that this salicylhydrazone is of mixed-type since it exhibits both anodic and cathodic corrosion inhibition performance. This inhibitor adsorbs and forms a protective barrier on the metal surface by a simple geometrical blocking of the active sites of this surface. Its adsorption proceeds essentially via physisorption mode and obeys the Langmuir's isotherm model. The density functional theory (DFT) calculations revealed the HBMH’s electron donor-acceptor nature, which may facilitate its adsorption on the XC38 steel surface. [Display omitted] •New salicylhydrazone derivative as efficient inhibitor for XC38 steel corrosion.•This is a mixed-type compound with reduced anodic and cathodic half-reactions rates.•Adsorption obeys Langmuir isotherm model and involves physicochemical interactions.•Strong electron donor-acceptor interactions with iron atoms mediate the adsorption.