Stress Corrosion Cracking and the Effects of <i>Citrus x aurantiifolia</i> on Mild Steel - A Green Approach

Abstract

The inhibition performance of citrus x aurantiifolia extract (CXA) on the corrosion of mild steel in 1.5 M H2SO4, 2 M H2SO4, 3 M H2SO4, and 4 M H2SO4 solutions was evaluated by weight loss, potentiodynamic polarization techniques, and scanning electron spectroscopy equipped with energy-dispersive X-ray spectroscopy. CXA inhibited the mild steel corrosion in the sulphuric acid solutionswith optimal inhibition results of 96.06% in 1.5 M H2SO4 and 86.57% in 4 M H2SO4 from weight loss measurement. Weight loss, potentiodynamic polarization, and scanning electron microscopy tests confirm the inhibitive performance of this compound and the increase in inhibitor efficiency increases with inhibitor concentration. The polarization data showed that the inhibitor acts as a mixed-type inhibitor, and fits the Langmuir adsorption isotherm. The adsorption studies clarify the excellent adsorption of this compound on the mild steel surface. The inhibited steel in the acid solution displayed improved surface morphology due to the surface protection effect of CXA molecules. The citrus x aurantiifolia studied here easily mitigates the effect of stress corrosion cracking on mild steel in a sulphuric acid environment. Keywords: Mild steel, Stress corrosion, Adsorption, Corrosion inhibitor, Sulphuric acid, Citrus X Aurantiifolia