K.F. Khaled

The inhibition of benzimidazole derivatives on corrosion of iron in 1 M HCl solutions

The inhibitive action of some benzimidazole derivatives namely 2-aminobenzimidazole (AB), 2-(2-pyridyl)benzimidazole (PB), 2aminomethylbenzimidazole (MB), 2-hydroxybenzimidazole (HB) and benzimidazole (B), against the corrosion of iron (99.9999%) in solutions of hydrochloric acid has been studied using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). At inhibitor concentration range (10 3 /10 2 M) in 1 M acid, the results showed that these compounds suppressed both cathodic and anodic processes of iron corrosion in 1 M HCl by adsorption on the iron surface according to Langmuir adsorption isotherm. The efficiency of these inhibitors increases in the order AB/PB/MB/HB/B. Both potentiodynamic and EIS measurements reveal that these compounds inhibit the iron corrosion in 1 M HCl and that the efficiency increases with increasing of the inhibitor concentration. Data obtained from EIS were analyzed to model the corrosion inhibition process through equivalent circuit. A correlation between the highest occupied molecular orbital EHOMO and inhibition efficiencies was sought. # 2003 Elsevier Science Ltd. All rights reserved.

4-Aminoantipyrine as an inhibitor of mild steel corrosion in HCl solution

Abstract4-aminoantipyrine (AAP) was tested as a corrosion inhibitor for mild steel in 2 M HCl solution using different techniques: weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results showed that AAP is an inhibitor for mild steel in this medium. The inhibition was assumed to occur via adsorption of the inhibitor molecule on the metal surface. In the 20 to 60 ∘C temperature range, the AAP adsorption follows the Flory–Huggins isotherm and/or the El-Awady et al. kinetic-thermodynamic model. The protection efficiency increases with increasing inhibitor concentration (in the range 10−310−2 M) but decreases with increasing temperature. The thermodynamic functions of dissolution and adsorption processes were calculated.

Investigation of the inhibitive effect of ortho-substituted anilines on corrosion of iron in 1 M HCl solutions

The inhibitory activity of some o-substituted anilines on iron corrosion in hydrochloric acid (HCl) was studied in relation to inhibitor concentration using potentiodynamic and electrochemical impedance spectroscopy (EIS) measurements. O-substituted anilines were found to act as mixed type inhibitors. The results showed that o-substituted anilines suppressed both cathodic and anodic processes of iron corrosion in 1 M HCl by its adsorption on the iron surface according to Langmuir adsorption isotherm. Potentiodynamic and EIS measurements reveal that these compounds inhibit the iron corrosion in 1 M HCl and that the efficiency increases with increasing of the inhibitor concentration. Data obtained from EIS are analyzed to model the corrosion inhibition process through equivalent circuit.

Piperidines as corrosion inhibitors for iron in hydrochloric acid

The objective of this work is to provide additional insight on the influence of substituents on heterocyclic piperidine as acid corrosion inhibitors for iron. This series include piperidine and six derivatives. The inhibiting properties of piperidine and these derivatives were investigated in 1 M HCl by potentiodynamic polarization (dc) and electrochemical impedance spectroscopy measurements, and inhibition was found to increases as 26dp < 35dp < 2mp < 3mp < pip < 4bp < 4mp. Polarization curves suggest that they can all be considered as mixed-type inhibitors. An attempt to correlate electronic properties of the compounds with their experimental efficiencies using molecular orbital calculation methods did not show any clear-cut relationship.

N‐heterocyclic amines and derivatives as corrosion inhibitors for iron in perchloric acid

Purpose – Work reported in the present paper investigated the inhibiting properties of a number of N‐heterocyclic amines in 0.1 mol/l HClO4. An attempt also was made to correlate some molecular parameters of these compounds with their corrosion inhibitor efficiency.Design/methodology/approach – The test series included piperidine (pip), 2‐methylpiperidine (2mp), 3‐methylpiperidine (3mp), cis‐2,6‐dimethylpiperidine (26dp), 3,5‐dimethylpiperidine (35dp), 3‐hydroxy piperidine (3hp), 4‐hydroxypiperidine (4hp), 4‐aminopiperidine (4ap), piperazine (pz), 2‐methylpiperazine (2mpz) and cis‐2,6‐dimethylpiperazine (26dpz). The inhibiting effect was investigated in 0.1& mol/L HClO4 by potentiodynamic polarization (DC) and electrochemical impedance spectroscopy (EIS).Findings – The results show that these compounds suppressed both cathodic and anodic processes of iron corrosion in 0.1 mol/l HClO4 by adsorption on the surface, which followed a Langmuir adsorption isotherm. Experimental observations indicated that basic...

Understanding Corrosion Inhibition of Mild Steel in Acid Medium by Some Furan Derivatives: A Comprehensive Overview

The inhibition performance of some furan derivatives, namely, methyl 2-furoate, ethyl 2-furoate, and amyl 2-furoate on mild steel in normal hydrochloric acid medium (1 M HCl) at 25°C, was studied by weight loss, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and electrochemical frequency modulation measurements (EFM). Furan derivatives inhibit the acidic corrosion even at very low concentrations, reaching a value of inhibition efficiency up to 93% at a concentration of 20 mM. The results obtained from the different corrosion evaluation techniques are in good agreement. Polarization curves indicate that the studied furan derivatives are mixed-type inhibitors. Data obtained from EIS measurements were analyzed to model the corrosion inhibition process through an appropriate equivalent circuit model. A constant phase element has been used. The adsorption of furan derivatives on the steel surface in 1 M HCl solution was found to obey Langmuirs adsorption isotherm with a negative value of the free energy of adsorption ΔG° ads+ Molecular dynamics simulations were carried out to establish the inhibition mechanism.

Scientific fraud in corrosion science research: A review

This article examines the issue of scientific misconduct and its implications on corrosion science research through a decade (2001–2011). An analysis is presented of an increasing body of cases in which allegations have been made and violations of legal and ethical research standards have been substantiated. The frequencies with which scientists fabricate and falsify data, or commit other forms of scientific misconduct, are discussed. In this review, the image of scientists as objective seekers of truth is periodically jeopardized by the discovery of a major scientific fraud. This review shows how easy it can be for a scientist to publish fabricated data in the most prestigious journals, and how this can cause a waste of financial and human resources. Case examples illustrated and investigated in this review are related to corrosion science research. Recommendations toward the prevention and resolution of potential or actual instances of scientific misconduct in corrosion science research are proposed.

Scientific fraud and the power structure of science

Scientific research typically has been established on high ethical standards created by researchers in research institutions and universities. Scientific misconduct violates these ethical standards. It can take different shapes, such as plagiarism, falsification of data, and irresponsible authorship. The primary focus of this paper is to show the most extreme cases of fraud which are obvious: manufacturing data and altering experimental results. This is illustrated by showing the fraudulent misconduct in an article published in a corrosion science journal in order to encourage the scientific community to develop mores and guidelines that prescribe professional conduct in the routine developing and publishing of scientific works. This paper also presents a proposal that involves conducting data audits of submitted manuscripts to prevent the publication of fraudulent work. The few cases described in this article serve as a ritual cleaning of the house of science. It helps to paint the rest of scientific behavior as blameless.

Scientific integrity in the digital age: data fabrication

Scientific society is unable to effectively define the boundaries between fraudulent acts and examples of poor science. This article examines the current level of fraud (especially data fabrication) and presents a proposal that involves conducting data audits of submitted manuscripts to prevent the publication of fraudulent work. Similar to the legal and medical professions, the relatively narrow-minded academic scientific community has always preferred to deal with instances of fraud and misconduct quietly, without external intervention. Recent highly publicized instances of scientific misconduct have stunned the electrochemical community, renewing calls for different approaches to address this growing threat to the position and trust of science within our society and, consequently, the generous public funding of academic research.