Corrosion behavior of two based aluminum materials for automotive industry when they are used with an industrial cooling liquid

The behavior of two based aluminum materials: an Al-Mn alloy and a 'sandwich material' (core of AlMn and on both sides a thin layer of AlSi) was studied in an industrial cooling liquid, Glaceol RX Tip D, containing ethylene - glycol and tolytriazole, as a corrosion inhibitor, the exact amount of which is not known. The sandwich material exhibits, at room temperature and in temperature cycles conditions, a better behavior. The dilution influence was too studied: nature and amount of used water (de-ionized or not). This behavior was determined with classical electrochemical techniques completed by post metallographic observations. To prevent environment pollution, we tested the possibility to use as a 'green' corrosion inhibitor a garlic extract, the active compound of which is allicine, that acts as an anodic inhibitor and leads to a protective film. The adsorption of the extract on the aluminum follows Langmuir adsorption isotherm.