Inhibition of the Al-Mg alloy in chloride solutions by means of rosmarinus officinalis L.
Aluminium alloys with magnesium are of special importance for technical applications. They are used as an important construction material in shipbuilding and in conditions which require high corrosion resistance, especially in sea water and near the sea. These alloys are also important in manufacture of equipment for the chemical and food-processing industry. The presence of aggressive ions, like chloride, leads to a strong local attack due to adsorption of these ions to those areas of the surface where the oxide film is weaker. Application of organic inhibitors in highly corrosive media is a widely spread method of minimising corrosion damages in a number of technologies. However, most commercial inhibitors used for this purpose are toxic and their replacement with other non-toxic ones in the future is unavoidable. The aim of the present study was to find less toxic inhibitor compounds for aluminium alloy corrosion. To that purpose the extract of rosemary leaves was tested for efficiency as a corrosion inhibitor for the Al-2.5Mg alloy. Rosmarinus officinalis L. is an aromatic plant of Mediterranean origin with outstanding antioxidant and antimicrobial properties. Extract examined is an effective inhibitor of the localized attack. The inhibitory action decreases with the decreasing concentration of additive.