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Article
Publication date: 1 August 2005

M. Bouklah, B. Hammouti, M. Benkaddour, A. Attayibat and S. Radi

To study the effect of inhibition of new bipyrazole derivatives on the corrosion of steel in HCl media at various temperatures.

Abstract

Purpose

To study the effect of inhibition of new bipyrazole derivatives on the corrosion of steel in HCl media at various temperatures.

Design/methodology/approach

In this study, novel corrosion inhibitors, namely bipyrazoles were synthesised and tested as corrosion inhibitors for steel in 1 M HCl. The degree of corrosion was measured using various techniques including weight loss measurements, potentiodynamic polarisation, linear polarisation resistance (Rp) and impedance spectroscopy (EIS).

Findings

It was found that 1,5,5′‐trimethyl‐1H,2′H‐3,3′‐bipyrazole (P1) gave the best inhibition effect. The inhibition efficiency increased with the concentration of P1 to attain 79 per cent at 10−3M. Good agreement between the various methods explored was observed. Polarisation measurements also showed that P1 acted essentially as a cathodic inhibitor. The cathodic curves indicated that the reduction of proton at the steel surface was an activating mechanism. P1 adsorbed on the steel surface according to Frumkin adsorption model.

Research limitations/implications

The synthesis route offers the possibility of other pyrazolic compounds to be tested in the future.

Practical implications

The inhibitory efficiency of P1 increased with the increase of both the concentration and the temperature (in the 298‐353 K range). As such, P1 can be used in chemical cleaning and pickling processes.

Originality/value

The originality of this work is the synthesis of new inhibitors based on pyrazolic organic compounds.

Details

Pigment & Resin Technology, vol. 34 no. 4
Type: Research Article
ISSN: 0369-9420

Keywords

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Article
Publication date: 1 January 2016

Basak Dogru Mert, Mehmet Erman Mert, Gülfeza Kardas and Birgül Yazici

The purpose of this paper is to investigate the adsorption and corrosion inhibition of two isomeric compounds (C4H5N3) as aminopyrazine (AP) and 2-amino-pyrimidine (2AP…

Abstract

Purpose

The purpose of this paper is to investigate the adsorption and corrosion inhibition of two isomeric compounds (C4H5N3) as aminopyrazine (AP) and 2-amino-pyrimidine (2AP) on mild steel (MS) in 0.5 M HCl. The study was a trial to combine experimental and modelling studies and research effect of molecular geometry on inhibition effect of inhibitor molecules.

Design/methodology/approach

The thermodynamic, kinetic and quantum parameters were determined. The electrochemical impedance spectroscopy and anodic polarisation measurements were obtained. The scanning electron microscope was used for monitoring electrode surface. The highest occupied molecular orbital, energy of the lowest unoccupied molecular orbital, Mulliken and natural bonding orbital charges on the backbone atoms, absolute electronegativity, absolute hardness were calculated by density functional theory (DFT)/B3LYP/6-311G (++ d,p).

Findings

Results showed that AP and 2AP suppressed the corrosion rate of MS. The corrosion current values were 0.530, 0.050 and 0.016 mA cm-2 in HCl, AP and 2AP containing HCl solutions, respectively. It was illustrated with the blocked fraction of the MS surface by adsorption of inhibitors which obeyed the Langmuir isotherm. The inhibition efficiency follows the order: 2AP > AP which is in agreement with experimental and quantum results.

Originality/value

This paper provides lay a bridge on the molecular geometry and inhibition efficiency by electrochemical tests and modelling study. The inhibition effect of AP and 2AP has not been compared with each other, neither experimentally nor theoretically. This study put forward possible application of 2AP as corrosion inhibitor especially for closed-circuit systems.

Details

Anti-Corrosion Methods and Materials, vol. 63 no. 5
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 4 September 2017

Asmae Bouoidina, Mehdi Chaouch, Abdelfattah Abdellaoui, Amal Lahkimi, Belkheir Hammouti, Fadoua El-Hajjaji, Mustapha Taleb and Ayssar Nahle

The inhibition effect of Foeniculum vulgare seeds’ (FVS) extract on the corrosion of mild steel in acidic medium was studied using weight loss, electrochemical impedance…

Abstract

Purpose

The inhibition effect of Foeniculum vulgare seeds’ (FVS) extract on the corrosion of mild steel in acidic medium was studied using weight loss, electrochemical impedance spectroscopy and Tafel polarization, as well as the surface morphology of the mild steel.

Design/methodology/approach

Weight loss measurements, potentiodynamic tests, electrochemical impedance spectroscopy studies and gas chromatography/mass spectrometry and scanning electron microscopy analysis of FVS extract were performed.

Findings

FVS extract acts as a good inhibitor for the corrosion of mild steel in 1.0 M HCl. The inhibition efficiency increases with the increase in inhibitor concentration but decreases with the increase of temperature.

Practical implications

FVS extract was observed to play an important role in the corrosion inhibition of mild steel in acidic solution.

Originality/value

This paper is intended to be added to the family of green inhibitors which are highly efficient inhibitors and can be used in the area of corrosion prevention and control.

Details

Anti-Corrosion Methods and Materials, vol. 64 no. 5
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 2 November 2015

Y. Sangeetha, S. Meenakshi and C. Sairam Sundaram

– The purpose of this paper is to develop an eco-friendly corrosion inhibitor for mild steel in 1 M HCl.

Abstract

Purpose

The purpose of this paper is to develop an eco-friendly corrosion inhibitor for mild steel in 1 M HCl.

Design/methodology/approach

A pharmaceutical drug acetyl G was investigated for its corrosion inhibition efficiency using weight loss method, potentiodynamic polarisation and electrochemical impedance spectroscopy.

Findings

The inhibition efficiency increased with increase in inhibitor concentration. Results from polarisation studies revealed mixed type of inhibition. Impedance studies, scanning electron microscopy and Fourier transform spectroscopy confirm the adsorption of inhibitor on the mild steel surface.

Research limitations/implications

The drug acetyl G has sulphur and nitrogen atoms which effectively block the corrosion of mild steel and is non-toxic and has good inhibition efficiency.

Practical implications

This method provides an excellent, non-toxic and cost-effective material as a corrosion inhibitor for mild steel in acid medium.

Originality/value

Application of this drug as a corrosion inhibitor has not been reported yet in the literature. Replacing the organic inhibitors, this green inhibitor shows excellent inhibition efficiency. This is adsorbed excellently on the mild steel surface due to the presence of long chain and hetero atoms. Thus, the drug retards the corrosion reaction.

Details

Pigment & Resin Technology, vol. 44 no. 6
Type: Research Article
ISSN: 0369-9420

Keywords

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Article
Publication date: 1 June 2015

Asiful Hossain Seikh and Mohammad Rezaul Karim

The purpose of this paper is to evaluate the effect of thiourea (TU) on corrosion resistance property for rolled and recrystallized E-34 microalloyed steels by using…

Abstract

Purpose

The purpose of this paper is to evaluate the effect of thiourea (TU) on corrosion resistance property for rolled and recrystallized E-34 microalloyed steels by using electrochemical polarization techniques.

Design/methodology/approach

To perceive the effect of TU on the corrosion inhibition efficiency, various concentrations of TU (from 1 × 10 − 4 to 1 × 10 − 2M) and different temperatures (20, 30 and 400°C) in 1N sulfuric acid are used.

Findings

It is found that TU has significant inhibition effect on corrosion process. Moreover, it reveals that both the inhibitor concentrations and temperatures have a strong influence on the corrosion prevention efficiency of inhibitor. Thermodynamics studies confirm that the inhibitor adsorption follows the Langmuir adsorption isotherm model.

Originality/value

To the best of the authors’ knowledge, it is the first work that has been disclosed the corrosion inhibitory effect of TU for recrystallized E-34 microalloyed steels in acidic media.

Details

Anti-Corrosion Methods and Materials, vol. 62 no. 4
Type: Research Article
ISSN: 0003-5599

Keywords

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Article
Publication date: 7 September 2015

Shabnam Ashhari and Ali Asghar Sarabi

– This paper aims to investigate the corrosion inhibition effects of indole-3-carbaldehyde and 2-methylindole on mild steel in 1 M HCl solution.

Abstract

Purpose

This paper aims to investigate the corrosion inhibition effects of indole-3-carbaldehyde and 2-methylindole on mild steel in 1 M HCl solution.

Design/methodology/approach

Indole-3-carbaldehyde and 2-methylindole as corrosion inhibitors of mild steel in 1 M HCl solution were investigated by polarisation and electrochemical impedance spectroscopy (EIS). Adsorption isotherm and mechanism were calculated. Quantum chemical calculations were used to find out a correlation between electronic structure of inhibitors and inhibition efficiency. Changes in the properties of metal surface in HCl solution in the presence of inhibitors were studied by contact angle measurements.

Findings

Polarisation results revealed inhibitors could reduce cathodic and anodic reactions rates on metal surface. EIS analysis showed that inhibition efficiency of indoles increases by increasing the inhibitors’ concentration; maximum inhibition efficiency was 95 and 94 per cent in solutions containing 1 mM indole-3-carbaldehyde and 2-methylindole, respectively. Inhibitors’ adsorptions on metal surface were confirmed by analysing the exposed metals’ surface through contact angles measurements. The adsorption of inhibitors was found to follow Langmuir isotherm. Quantum chemical calculations showed that a more positively charged benzene ring in the structure of two indole-based inhibitors would lead to higher adsorption to metal.

Originality/value

This research was carried out to understand the effects of two different functional groups (-C=O, -CH3) with different induction effects on the indole structure and on inhibition efficiency of corrosion inhibitors with the purpose of using these components in industrial application as acid wash solutions to etch and remove rusts from metal surfaces.

Details

Pigment & Resin Technology, vol. 44 no. 5
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 16 April 2018

Karima Dob, Emna Zouaoui and Daoiya Zouied

Electrochemical measurements were used to characterize the inhibiting effectiveness of Curcuma and saffron, considered as green inhibitors in a corrosive environment 3…

Abstract

Purpose

Electrochemical measurements were used to characterize the inhibiting effectiveness of Curcuma and saffron, considered as green inhibitors in a corrosive environment 3% NaCl on A106 Gr B carbon steel.

Design/methodology/approach

This study/paper aims to polarization and potentiodynamic impedance spectroscopy techniques were performed on A106 Gr B carbon steel in the 3% NaCl environment only and containing various concentrations of Curcuma and Saffron (0.005, 0.01, 0.02, 0.04, g/L) after 30 min of immersion; these measures were taken at a temperature of (298 ± 1)K. A voltlab PGZ 301 assembled by A 106 Gr B carbon steel working electrode, a platinum counter electrode (CE) and a saturated calomel electrode as the reference electrode were used in the experiment. In this research, potentiodynamic polarization and electrochemical impedance spectroscopy were used.

Findings

The inhibition efficiencies increased with increase in the concentrations of the inhibitor but decreased with rise in temperature. The obtained results show an optimal efficiency with 0.04 g/L which are ordered of 78 and 96 per cent successively for the two inhibitors. Curcuma and saffron acts as a mixed type inhibitor. Adsorption of the inhibitor molecules corresponds to Langmuir adsorption isotherm. Mechanism of inhibition was also investigated by calculating the thermodynamic and activation parameters like (ΔG), (Ea), (ΔHa) and (ΔSa). The inhibitor molecules followed physical adsorption on the surface of carbon steel.

Originality/value

The present trend in research on environmental friendly corrosion inhibitors is concentrating on products of natural origin due principally to non-toxicity and eco-friendliness. Among these natural products are curcuma and saffron.

Details

Anti-Corrosion Methods and Materials, vol. 65 no. 3
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 6 November 2009

Emeka Oguzie, Chris Akalezi and Conrad Enenebeaku

The purpose of this paper is to study methyl green dye (MG) as a corrosion inhibitor for low carbon steel (LCS) in hydrochloric acid (1 M) and sulphuric acid (0.5 M) and…

Abstract

Purpose

The purpose of this paper is to study methyl green dye (MG) as a corrosion inhibitor for low carbon steel (LCS) in hydrochloric acid (1 M) and sulphuric acid (0.5 M) and to assess the effect of temperature variation and halide additives on the inhibition efficiency.

Design/methodology/approach

Corrosion rates are monitored using the gravimetric technique. Inhibition efficiency is determined by comparing the corrosion rates in the absence and presence of additives. Attempts are also made to elucidate the inhibition mechanism from the trend of inhibition efficiency with change in temperature and type of acid anion.

Findings

MG reduces the corrosion rate of the LCS specimens in both acid media within the investigated temperature range by adsorption at the metal/solution interface. Inhibition efficiency increases with MG concentration but decreases with rise in temperature. Maximum values of 67 and 73 per cent are obtained in 1 M HCl and 0.5 M H2SO4, respectively, at [MG]=0.001 mol dm−3. Halide additives increase the inhibition efficiency mainly in the sulphuric acid medium.

Research limitations/implications

The inhibiting effect of MG is studied within a fixed concentration range, which can be expanded for further studies. The same applies to the effect of halide additives. Also, the dye structure can be modified by introducing different functional groups, and the effect on inhibition efficiency is investigated.

Practical implications

The research findings can find practical application for corrosion control in aqueous acidic environments.

Originality/value

This paper provides new information on the application of MG for corrosion inhibiting purposes. The experimental results form part of an extensive database on the corrosion inhibiting characteristics of organic dyes.

Details

Pigment & Resin Technology, vol. 38 no. 6
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 24 May 2011

Aprael S. Yaro, Anees A. Khadom and Hadeel F. Ibraheem

The aim of this paper is to investigate peach juice as a cheap, raw, green and non‐toxic anti‐corrosion material for mild steel corrosion in hydrochloric acid at different…

Abstract

Purpose

The aim of this paper is to investigate peach juice as a cheap, raw, green and non‐toxic anti‐corrosion material for mild steel corrosion in hydrochloric acid at different temperatures.

Design/methodology/approach

The corrosion inhibition of mild steel in 1 M HCl solution in the presence of peach juice at temperature range of 30‐60°C and concentration range of 5‐50 cm3/l was studied using weight loss and polarization techniques. The inhibition effect, adsorption characteristics, mathematical and electrochemical modeling of peach juice were addressed.

Findings

Results show that inhibition efficiency rose with the increase of inhibitor concentration and temperature up to 50°C, while at temperatures above 50°C the values of efficiency decreased. The inhibitor adsorbed physically on metal surface and followed the Langmuir adsorption isotherm. Monolayer formed spontaneously on the metal surface. Maximum inhibition efficiency obtained was about 91 percent at 50°C in the 50 cm3/l inhibitor concentration.

Originality/value

This work is an attempt to find a new, safe to environment, non‐toxic corrosion inhibitor. Peach juice is a readily available material in Iraq and Middle East markets.

Details

Anti-Corrosion Methods and Materials, vol. 58 no. 3
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 26 August 2014

B.P. Markhali, R. Naderi, M. Sayebani and M. Mahdavian

The purpose of this paper is investigate the inhibition efficiency of three similar bi-cyclic organic compounds, namely, benzimidazole (BI), benzotriazole (BTAH) and…

Abstract

Purpose

The purpose of this paper is investigate the inhibition efficiency of three similar bi-cyclic organic compounds, namely, benzimidazole (BI), benzotriazole (BTAH) and benzothiazole (BTH) on carbon steel in 1 M hydrochloric acid (HCl) solution. Organic inhibitors are widely used to protect metals in acidic media. Among abundant suggestions for acid corrosion inhibitors, azole compounds have gained attention.

Design/methodology/approach

The inhibition efficiency of the three organic compounds was investigated using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS).

Findings

Superiorities of BTH and BTAH corrosion inhibitors were shown by EIS data and polarization curves. Moreover, the results revealed that BTAH and BTH can function as effective mixed-type adsorptive inhibitors, whereas no inhibition behavior was observed for BI. Both BTAH and BTH obeyed Longmuir adsorption isotherm. The results obtained from this isotherm showed that both inhibitors adsorbed on the specimen surface physically and chemically. The difference in inhibition efficiencies of BTAH, BTH and BI was related to the presence of nitrogen and sulfur hetero atoms on their molecular structures.

Originality/value

This study evaluated inhibition efficiency of BI, BTAH and BTH using electrochemical methods. In addition, the study attempted to find inhibition mechanism of the inhibitors and to find modes of adsorption of the inhibitors, correlating effects of heteroatoms and inhibition efficiency.

Details

Anti-Corrosion Methods and Materials, vol. 61 no. 5
Type: Research Article
ISSN: 0003-5599

Keywords

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