The effects of the modification of the pH in 0.1 M cerium nitrate solutions in the elaboration and corrosion resistance of ceria based coatings on carbon steel are investigated. Increasing the concentration of acetic acid impedes an efficient electrodeposition. At low concentrations, acetic acid seems to prevent the precipitation of Ce(OH)3 and the formation of even films of cerium oxides is favored. The increase of pH through the addition of NaOH to the cerium nitrate solutions with 0.008 M of acetic acid is shown to provide superior corrosion resistance for exposures in air and immersed in 0.5 M NaCl for 30 days.

This work investigates the synthesis and the corrosion inhibitor efficiency ceria nanoparticles may exert on steel reinforcement in an alkaline solution of saturated Ca(OH)2 + 0.5 M CaCl2 up to 50°C. The corrosion mechanisms are thoroughly investigated by electrochemical and various characterization techniques. The electrochemical results show that ceria nanoparticles act as an anodic inhibitor and provide maximum inhibition efficiency (80%) at a concentration of 800 ppm. The resulting surface is smooth and free from corrosion products due to the formation of a physically adsorbed film according to the thermodynamic calculations.

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Corrosion of steel in reinforcement concrete is complex. When chloride ions and oxygen reach reinforcing steel, corrosion is initiated. The deterioration process starts with expansions of the bare steel substrate then after cracks in the concrete are developed. The aim of this work is to determine firstly, through the electrochemical technic, the critical concentration of chloride ions which are responsible for the initiation of the dissolution step. Then, the effect of the external parameters on the rate of penetration of the chloride ions into the concrete are also evaluated. For this propose, the electrochemical behavior of the steel of construction “E24” is studied in carbonate medium without and with different concentrations of chloride ions. The effect of various parameters such as temperature, ions concentration and solution pH was also evaluated through the evolution of the open circuit potential, d.c polarization measurement and electrochemical impedance spectroscopy. The d.c polarization and EIS results shows that the addition of 0.5M CaCl2 (as critical concentration) to the saturated Ca(OH)2 solution, brings to a rapid and a continuous dissolution of the substrate where after 3 hours of immersion time the whole surface of the substrate was covered the corrosion products. This is may be due to specific adsorption of Cl-.