Inhibition of Mild Steel Corrosion in Acid Medium

Abstract

Since inhibition is the simplest mechanism used for mitigating the corrosion of metals and alloys, particularly in acidic environments, the present work aims to investigate the inhibiting effect of N-benzyl-N′-phenyl thiourea (BPTU) and N-cyclohexyl-N′-phenyl thiourea (CPTU) on mild steel corrosion in 0.1M HCl medium using the Tafel extrapolation technique. Tafel experiments were conducted with ±250 mV vs. rest potential (RP) in steps of 20 mV from the cathodic side for recording the corrosion currents, and then, the Tafel plot of potential vs. current was drawn for determining the corrosion current density (icorr). The linear polarization method was also used for validating the Tafel results. It was performed by polarizing the specimen with ±20 mV vs. RP in steps of 5 mV, and the corrosion currents were noted. The plot of potential vs. current was drawn for calculating icorr. The study reveals that both BPTU and CPTU act as anodic inhibitors for mild steel in the HCl medium, and good inhibition efficiency (>97%) was evidenced from both the compounds even at elevated temperatures. The study also reveals that the investigated compounds get adsorbed quickly on the steel surface, following Temkin's adsorption isotherm. The kinetic parameters obtained from the study indicated that the inhibition was governed by a chemisorption mechanism and the presence of inhibitors substantially reduced the metal dissolution in the studied temperature range. The investigation shows that there was a good correlation between the Tafel extrapolation and linear polarization results.

A Simple Technique for the Corrosion Inhibition of Underwater Cannonball from a Shipwreck

“…Several methods have been developed for the conservation of underwater cannonball heritage, such as cathodic protection (Bethencourt et al, 2018;Angelini, Grassini, and Tusa, 2013;Heldtberg, Macleod, and Richards, 2004), aerated and deaerated using NaOH solutions (Kergourlay et al, 2018), using natural products (Abdel-Karim and El-Shamy, 2022;Verma et al, 2017;Palou, Olivares-Xomelt, and Likhanova, 2014;Cano and Lafuente, 2013;Kesavan, Gopiraman, and Sulochana, 2012). Several natural products and chemicals have been used as green corrosion inhibitors, such as anthill (Myrmecodia Pendans) extract (Pradityana et al, 2017); acid medium (Shetty and Shetty, 2017); malonic acid and succinic acid (Thaha et al, 2019). The final stage after corrosion stops on underwater cannonball heritage is coating.…”

An Anticorrosion Coating from Ball-milled Wood Charcoal and Titanium Dioxide using a Flame Spray Method

“…These terms refer to the medium in which the deposited material is processed. Wet-coating methods mainly involve electroplating (Lowenheim & Senderoff, 1964), electroless plating (Mallory & Hajdu, 1990), hot-dip galvanizing (Rahrig, 1995), and corrosion-inhibitor addition (Shetty & Shetty, 2017); dry-coating methods include, among others, vapor deposition (Pierson, 1999), thermal spray 984 An Anticorrosion Coating from Ball-milled Wood Charcoal and Titanium Dioxide using a Flame Spray Method techniques (Davis, 2004;Pawlowski, 2008), brazing (Schwartz, 2003;Shapiro & Rabinkin, 2003), weld overlays (Hattori & Mikami, 2009), and peening and nitriding (Ariati et al, 2016).…”