Effets des inhibiteurs verts sur la corrosion des aciers ordinaires dans deux milieux acides.

Type : Thèse de doctorat
Auteur(s) :  OULABBAS Amel
Directeurs du mémoire/thèse :  -
Année :  2019
Domaine : Chimie
Etablissement :  Université Badji Mokhtar de Annaba
Résumé en PDF :  (résumé en pdf)
Fulltext en PDF :  (.pdf)
Mots clés :  corrosion, O.F.I, Aloe Vera, EIS, green inhibitor, mild steel.

Résumé :

The cladodes extract of Opuntia Ficus Indica (O.F.I) wich is found in eastern of Algeria (Annaba) and Aloe Vera brought from North America, were the object of our work with the aim of studying their inhibitory efficiencies, on two different mild steels, and in three acidic environments, 1M H3PO4, 0.5M H3PO4 and 0.5M H2SO4. To do so, several analytical methods were used, such as gravimetry, stationary electrochemical methods (potentiodynamic polarization and chronoamperometry), transient electrochemical impedance spectroscopy (EIS) and the Zero-Charge Potential (PZC) method. Moreover, we used steel surface characterization methods, as the contact angle measurement method and Scanning Electron Microscopy (SEM). The obtained results, related to the inhibitory efficiency, were 97.6% and 80.9% respectively for O.F.I and Aloe Vera, separately used at 10% (v / v) of concentration. Whereas together, these two green inhibitors act as a mixed inhibitor and increase the polarization resistance, while increasing the inhibitor concentration. The synergy of the two extracts with and without the addition of KI, as an additive, improves the inhibitory efficiency by the increase of the polarization resistance. Then, based on the above experiments, we may quality this inhibitors case as physisorption of the tows inhibitors when used separately as well as in synergy. The characterizations of the surface condition of the two mild steel samples confirm the obtained results.Keywords: Corrosion,