Corrosion Engineering Science and Technology The International Journal of Corrosion Processes and Corrosion Control · 2019 · 10 citations · 26 references
Natural SciencesChemical EngineeringChemistryCorrosion ScienceElectroanalytical MethodsElectrochemistryCorrosion EngineeringCorrosion InhibitorsCorrosion Of SteelsCorrosion-resistant MaterialsElectrochemical CorrosionGalvanic CorrosionActive CorrosionCarbon Steel CorrosionCorrosion Inhibition MechanismsCorrosion Inhibitor EvaluationCorrosion Inhibitors For Carbon SteelElectrochemical Impedance AnalysisLangmuir Adsorption ModelSteric Constraints
In this work, the plant alkaloid Voacangine, isolated from the bark of Tabernaemontana contorta, was examined as a corrosion inhibitor for steel in 1 M hydrochloric acid. The study was carried out using a comparative approach where several independent methods (spectroscopic solution analysis, electrochemical impedance, potentiodynamic polarisation and mass loss measurements) were performed in order to strengthen the validity of the results. All the findings revealed to be in close agreement with each other. Voacangine was determined to be a mixed corrosion inhibitor and to closely follow Langmuir-type adsorption onto active corrosion sites on the metal surface. The maximal inhibition efficiency was 90% which is lower than other comparable species. This deficiency was ascribed to the presence of a basic nitrogen group causing a degree of steric hindrance for the adsorption.
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