Sinapinic acid as Al–2.5Mg alloy corrosion inhibitor in sodium chloride solution

Sinapinic acid was studied for possible use as an Al–2.5Mg alloy corrosion inhibitor in a 0.5 mol dm⁻³ NaCl solution. Measurements were performed on a rotating disc electrode in a quiescent solution and at different electrode rotation rates and electrolyte temperatures. Electrochemical parameters for the Al–2.5Mg alloy were determined using polarization techniques and electrochemical impedance spectroscopy (EIS). The investigated compound acts as a cathodic-type inhibitor and the inhibition is ascribed to the adsorption of the inhibitor onto the electrode surface. The electrode coverage follows the Freundlich adsorption isotherm.