Cerium Compounds Coating as a Single Self-Healing Layer for Corrosion Inhibition on Aluminum 3003

The formation of cerium hydroxide was studied, and its capacity as a corrosion inhibitor on aluminum substrates was evaluated. These particles were deposited by immersing the substrate in a bath with cerium nitrate and hydrogen peroxide. Four different immersion times were used to determine the differences in behavior from low concentrations to an excess of particles on the surface. The coatings were analyzed morphologically by scanning electron microscope (SEM) and optical microscope, and chemically by energy dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). Electrochemical corrosion analysis was studied using cyclic potentiodynamic polarization (CPP), electrochemical impedance spectroscopy (EIS), and electrochemical noise (EN). The results show that for 2 and 5 min of immersion, there was corrosion inhibition caused by the presence of cerium Ce³⁺ in the coating, but with excess cerium hydroxide particles, corrosion was favored. The presence of cerium particles favors corrosion at 30 s of immersion. This is the same case at 60 min, where corrosion was favored by the excess of Ce⁴⁺ particles on the surface.