Sinapis alba as an anti-rusting agent for corrosion of stainless steel in hydrochloric acid medium

Resumo

Protection against corrosion using Sinapis alba was studied for the corrosion control of stainless steel in 0.5 M HCl. The electrochemical techniques such as potentiodynamic polarization measurements and electrochemical impedance spectroscopy were used for the stainless steel protection studies. Surface morphology studies were done using scanning electron microscopy/energy dispersive X-ray analysis. Kinetic and thermodynamic parameters were evaluated and discussed. The mechanism for the corrosion inhibition was proposed. The obtained results showed that Sinapis alba acted as a mixed-type inhibitor, with the maximum inhibition efficiency of 88% for the concentration of 0.1 g L^–1 at 323K. It was chemically adsorbed on stainless steel and obeyed the Langmuir adsorption isotherm. Sinapis alba emerged as an effective eco-friendly corrosion inhibitor for the corrosion control of stainless steel in the HCl acid medium. Surface morphology studies confirmed the adsorption of this inhibitor onto the surface of the metal. The results obtained via potentiodynamic polarisation and electrochemical impedance spectroscopy was in agreement with each other.