Type : Mémoire de magister
Auteur(s) :  OULABBAS Amel
Directeurs du mémoire/thèse :  -
Année :  2013
Domaine : Chimie
Etablissement :  Université de Souk Ahras
Résumé en PDF :  (résumé en pdf)
Fulltext en PDF :  (.pdf)
Mots clés :  corrosion, cerium, chrome, inhibiteur de corrosion

Résumé :

In order to limit the degradation of steels in service, surface treatments are applied. Thecombination of different layers to protect materials against corrosion in a sustainable manner.Based compounds of hexavalent chromium have always been the most used in the aerospaceindustry because they are simple to implement and are recognized as the most effectiveinhibitors of steel corrosion. Recent European directives state that the use of compoundscontaining hexavalent chromium must be reduced or eliminated in the very near future, asthey have been recognized carcinogenic to humans and toxic to the environment. Manystudies have been made in recent years, but today, most alternatives do not pose the samelevel of performance as methods based on hexavalent chromium. An alternative treatmentspassivation uses rare earth oxides, in particular the Ce use the latter as an inhibitor to replacehexavalent chromium is characterized by forming thin layers is generally associated with theformation of oxides or hydroxides cerium cathodic sites of the metal surface. Theelectrochemical characterization of the inhibition process was evaluated in harshenvironments such as 0.1 M NaCl, 0.1M Na2SO4 and industrial water. Thus, the corrosionresistance obtained on steel A 366 was studied. For all samples, the duration of protection wasassessed by measurement of Ecorr. In parallel, the efficacy is monitored by measuring thepolarization resistance, the corrosion current density of the lines extrapolated from Tafelelectrochemical impedance spectroscopy. In conclusion, the results of analytical andelectrochemical techniques have shown that cerium may very well and with similar efficacyreplaced hexavalent chromium.