Synergistic Corrosion Inhibition of Mild Steel in Aqueous Chloride Solutions by an Imidazolinium Carboxylate Salt

Abstract

Mild steel infrastructure is constantly under corrosive attack in most environmental and industrial conditions. There is an ongoing search for environmentally friendly, highly effective inhibitor compounds that can provide a protective action in situations ranging from the marine environment to oil and gas pipelines. In this work an organic salt comprising a protic imidazolinium cation and a 4-hydroxycinnamate anion has been shown to produce a synergistic corrosion inhibition effect for mild steel in 0.01 M NaCl aqueous solutions under acidic, neutral, and basic conditions; an important and unusual phenomenon for one compound to support inhibition across a range of pH conditions. Significantly, the individual components of this compound do not inhibit as effectively at equivalent concentrations, particularly at pH 2. Immersion studies show the efficacy of these inhibitors in stifling corrosion as observed from optical, SEM, and profilometry experiments. The mechanism of inhibition appears to be dominated by anodic behavior where dissolution of the steel, and in particular the pitting process, is stifled. FTIR spectroscopy provides confirmation of a protective interfacial layer, with the observation of interactions between the steel surface and 4-hydroxycinnamate.

Passivation behaviour of aluminium current collector in ionic liquid alkyl carbonate (hybrid) electrolytes

“…The pipette cell used was previously described elsewhere. 24 The inner surface area of the pipette (equal to that of the working electrode W.E.) was 0.38 ± 0.05 cm 2 .…”

“…19 Recent studies examined the use of ionic liquids as electrolyte components in lithium batteries and selected ionic liquids were found to possess wide electrochemical stability, improved safety 15,17,[20][21][22] as well as corrosion inhibition properties. [23][24][25][26] It is interesting to note that the well-known corrosive nature of the LiTFSI salt is decreased when ionic liquids were added to the electrolyte composition. 17,27,28 In addition to the corrosion inhibition, the so-called passive films formed on the substrate in the presence of ionic liquid electrolytes show better thermal stability.…”

Emerging Corrosion Inhibitors for Interfacial Coating

“…Recently, Somers et al [41] described such a family of ILs and organic salts that target dual activity by incorporating both anions and cations with proven evidence of effective inhibition. These salts were based on the imidazolinium cation with carboxylate anions.…”

Synthesis, characterization and application of acrylate-based poly ionic liquid for corrosion protection of C1020 steel In hydrochloric acid solution

“…The Langmuir isotherm proposes a monolayer coverage of inhibitor molecules on the metal surface, while the El-Awady model proposes that the active site is covered with a multilayer [1,[66][67][68]. The Langmuir isotherm has the following expression [37]:…”

“…Although PILs have the same characteristics of ILs monomer, they can be adapted to provide specific properties as they can be tailored for a specific application by carefully selecting the cations, anions, functional groups, polymer backbone, and chain length [35]. Nowadays, these substances attract much attention in corrosion engineering because of their excellent wetting properties in addition to their effective adsorption over several substrates of metals in which the π-electrons in conjugation with active polar heteroatoms constitute as chelating centres [36,37].…”