Corrosion of aluminum in ascorbic, citric and tartaric acids with and without chloride ions

Abstract

PurposeThis paper seeks to study the corrosion rate (CR) of Al 6063 in aqueous solutions containing food additives, namely ascorbic, citric and tartaric acids with/without chloride ions.Design/methodology/approachChemical and electrochemical measurements were used to study the CR of Al 6063 in aerated aqueous solutions. Chemical measurements include weight loss (WL) and atomic absorption (AA). The surface morphology of Al 6063 was studied using scanning electron microscope connected with energy dispersion X‐Ray (EDX). Electrochemical measurements were made using a potentiostat/galvanostat; the effect of pH, temperature and immersion time was studied.FindingsAA gave comparable results to that of WL. EDX results showed the depletion of Mg and Fe from the Al 6063 to carboxylic acid solutions w/without NaCl. From electrochemical measurements, it was found that addition of chloride ions to carboxylic acids increased the CR of Al 6063 especially at low pH and high temperatures but it reduced the CR at long immersion times.Practical implicationsAluminum (Al) is now known to be a neurotoxin agent yet Al cook wares are widely used in different countries. The acids used in this study are food additives which implies that the Al cook wares may corrode in food containing these acids and other carboxylic acids depending on pH, temperature and the presence of other additives.Originality/valueAA gave comparable results to that of WL, which shows that it may be used to evaluate leaching metal ions in μg levels or less in corrosion measurements.