Inhibitive effect of 8-hydroxyquinoline on corrosion of gray cast iron in automotive braking systems.

The inhibition effect of 8-hydroxyquinoline (8-HQ) on the corrosion of gray cast iron rotors for automotive applications was studied by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) in a 0.1 M HCl solution. The experimental results suggest that the 8-hydroxyquinoline is a mixed inhibitor reducing both the anodic and the cathodic current densities. Besides, EIS results indicate that the inhibitor provides a stable protection over 9 days of exposure to the electrolyte due to the cooperative formation of an adsorbed layer of 8-HQ on the rotor and a top layer probably constituted by a complex between 8-HQ and iron. The presence of the adsorbed layer and the complex with 8-HQ was confirmed by means of Energy Dispersive X-ray analysis (EDX) and Fourier-transform spectroscopy (FT-IR). [ABSTRACT FROM AUTHOR]