Results in Chemistry (Jan 2024)
Electrochemical analysis of aluminium corrosion in alkaline battery fluid under the influence of Alizarin Red S and Xylenol Orange
Abstract
Aluminium is preferred over iron for various uses as it is lighter, rust-proof and has an exceptional strength-to-weight ratio. Aluminium is more reactive than iron because of its higher standard reduction potential but it forms a self-protective layer of Al2O3 due to its higher reducing potential. Still, aluminium is corroded in acidic and alkaline media. The present research paper reports the corrosion behaviour of aluminium in 0.1 M NaOH solution with Alizarin Red S (ARS) or Xylenol Orange (XO) as an inhibitor. Corrosion potential, Corrosion current, Tafel slopes (βc) and (βa) for aluminium corrosion have been potentiodynamically investigated. The weight loss method has also been used to calculate the inhibition efficiencies of these additives. The corroded surfaces have been characterized by SEM images. It is found that corrosion potential values change significantly towards the anodic direction in the presence of ARS but they are sifted towards a cathodic direction at a high concentration of XO. While ARS shows a corrosion inhibition effect, XO shows a reverse effect. The inhibition efficiency values of ARS and XO calculated from corrosion current in potentiodynamic polarization studies tally with those calculated from weight loss studies. Studies on a laboratory model of aluminium-air batteries in 0.1 M NaOH containing these organic additives show that the discharge curve of the cell is improved in the presence of ARS and XO in combination. The results are explained in terms of the formation of well-known Al+3.3ARS− and Al+3-XO6− complexes. At room temperature, 1.0 × 10−3 M solution of ARS is found effective in inhibiting the corrosion of aluminium while the same concentration of XO is acting as a corrosion accelerator. This interesting study can be very vital in the field of corrosion science.
