The influence of Lavandula angustifolia L. oil on corrosion of Al-3Mg alloy

Natural oil extracted from Lavandula angustifolia L. was investigated as corrosion inhibitor of Al-3 Mg alloy in 3% NaCl solution using weight loss, polarization measurements and SEM. The oil dissolved in ethanol and used as 30% (v/v) solution, was found to retard the corrosion rate of Al-3 Mg alloy even at high temperatures. The inhibiting effect of lavender oil components on Al-3 Mg surface was attributed to the Langmuir’s adsorption isotherm. It was found that the L. angustifolia L. oil provides a good protection to Al-3 Mg alloy against pitting corrosion in sodium chloride solution.

Research highlights
► Lavandula angustifolia L.   oil being a natural and environmentally benign product it can be used instead of toxic chemical inhibitors in preventing aluminium alloys from pitting corrosion.
► The increase of lavender oil concentration above a certain value has little effect on the surface coverage or inhibition efficiency.
► The lavender oil compounds adsorbed onto the metal surface follow the Langmuir adsorption isotherm.
► The values of ΔGads0 obtained support the mixed mode of adsorption (physisorption and chemisorption).