Corrosion inhibition of martensitic stainless steel by sodium benzoate in acidic medium: Solanum tuberosum extract as surfactant

Abstract

Research on corrosion inhibitor efficacy has been seen as essential to enhancing the robustness of martensitic stainless steel (MSS), which finds use in a variety of industrial settings. Thus, the aim of this study is to examine the inhibitory efficacy of sodium benzoate with solanum tuberosum (potato) extract as surfactant in a 0.5 M HCl solution for MSS. The techniques of electrochemical measurements and weight loss were adopted for the MSS samples cut into corrosion coupons and submerged in 0.5 M HCl solution at room temperature. A scanning electron microscopy equipped with an electron dispersive x-ray spectroscopy (SEM-EDS) was utilized for the morphology analyses of the samples. From the obtained results, the maximum inhibition efficiency of 32.58 % was recorded at 1.0 M inhibitor concentration, indicating that sodium benzoate is an effective corrosion inhibitor. It was noticed that the rise in the inhibitor concentration up to 1.0 M results in the reduction on corrosion rates being recorded, hence, the inhibition performance. However, 1.5 M and 2.0 M inhibitor concentration had higher corrosion rates compared to others. This study demonstrated that the inhibitor produces a film which adhere strongly to the MSS surface based on the Langmuir adsorption isotherm. Consequently, the combination of sodium benzoate with solanum tuberosum extract would be beneficial to significantly prolong MSS in industrial applications like oil drilling rigs, heat exchangers and marine installations.