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Article
Publication date: 1 December 2004

M. Elayyachy, M. El Kodadi, B. Hammouti, A. Ramdani and A. Elidrissi

The inhibition of corrosion of steel in 1 M HCl solution by newly synthesised pyrazole derivatives has been studied by weight loss and polarisation techniques at 308°K…

Abstract

The inhibition of corrosion of steel in 1 M HCl solution by newly synthesised pyrazole derivatives has been studied by weight loss and polarisation techniques at 308°K. Its inhibitory power is compared to N,N′‐bis(3,5‐dimethylpyrazol‐1‐yl‐methyl)‐pentanolamine (Bipyr). The results obtained reveal that tripyrazole exhibits a good protection. Inhibition is found to increase with increase in inhibitor concentration. The inhibition behaviour of the compound has been explained on the basis of molecule size and charge density of adsorption active centres. The adsorption phenomenon obeys the Langmuir adsorption isotherm model.

Details

Pigment & Resin Technology, vol. 33 no. 6
Type: Research Article
ISSN: 0369-9420

Keywords

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Article
Publication date: 13 November 2007

M. Benabdellah, R. Souane, N. Cheriaa, R. Abidi, B. Hammouti and J. Vicens

To evaluate the effect of synthesised calixarenes as new inhibitors on the corrosion of steel in HCl media at various temperatures.

Abstract

Purpose

To evaluate the effect of synthesised calixarenes as new inhibitors on the corrosion of steel in HCl media at various temperatures.

Design/methodology/approach

Calixarenes have been synthesised and tested as corrosion inhibitors. Gravimetric technique and potentiodynamic polarisation and impedance spectroscopy methods were used.

Findings

Calixarenes exhibited a good inhibition. Their efficiency decreases slightly with temperature.

Research limitations/implications

It was found that the inhibition efficiency increases with the concentration of inhibitors to reach 92 per cent at 10−4M.

Practical implications

The efficiency of calixarene derivatives increases with the concentration and falls slowly with temperature to attain 84 per cent at 353 K range. Calixarenes can be used in chemical cleaning and pickling processes.

Originality/value

The originality of this work is to find an inhibitor to give protection close to 100 per cent.

Details

Pigment & Resin Technology, vol. 36 no. 6
Type: Research Article
ISSN: 0369-9420

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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

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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

Keywords

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