In this article, different treatment baths for corrosion protection of 2030 aluminum alloy in addition to replacing the hexavalent chromium due to the European recommendation were employed. This work is divided into three steps of treatment: first, anodization using molybdate inhibitor without and with phosphoric acid and, then, pre-oxidation with sodium hydroxide. In the last step, we studied the influence of conversion coating with the combination of sodium molybdate and fluoride on the anodic layer formed on aluminum alloy 2030. In order to characterize the formed layers, we use microstructural characterization (SEM, AFM, and nano-indentation), which allows highlighting the surface condition as well as the morphological distribution, and electrochemical techniques such as potentiodynamic polarization and electrochemical impedance spectroscopy which shows that the anodization treatment of the aluminum alloy with phosphoric acid and sodium molybdate offered better corrosion resistance. This resistance increased with the use of pre-oxidation and then reached a maximum value of 99.8% efficiency with the addition of the molybdate conversion coating which causes an increase in the double layer and gave an alternative possibility of chromium VI.

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Improve the reliability of the gas and oil transportation process is a primary objective of the pipeline designers because it interests the safety of the goods and the people, the availability and the performance of pipelines as well as the economy of the hydrocarbon transport. Corrosion is a present phenomenon that occurs inside and outside of buried pipes, causing the pipeline to be pierced, leading to gas and oil leaks and causes consequences of the major economic losses. In this context, our study focused on the corrosion monitoring of metals used in the transport of hydrocarbons by two approaches based on electrochemical techniques. Monitoring the evolution of the corrosion potential using an elaborated reference instead of a commercial reference electrode, and by electrochemical impedance spectroscopy (EIS) coupled with the gravimetric method. The obtained results showed the efficiency of our approach for the realization of a corrosion sensor intended for the monitoring of corrosion in pipelines.