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Article
Publication date: 1 June 2002

A. El Ouafi, B. Hammouti, H. Oudda, S. Kertit, R. Touzani and A. Ramdani

The inhibition of the corrosion of the mild steel in 1M HCl by new bipyrazolic compounds has been studied by weight loss, electrochemical polarisation and electrochemical…

Abstract

The inhibition of the corrosion of the mild steel in 1M HCl by new bipyrazolic compounds has been studied by weight loss, electrochemical polarisation and electrochemical impedance spectroscopy (EIS) measurements. Results obtained reveal that these compounds are very good inhibitors. The inhibition efficiency increases with the increase of inhibitor concentration and reached 94 at 10–3M for the bipyrazoles studied. Potentiodynamic polarisation studies clearly reveal that the presence of the bipyrazoles does not change the mechanism of the hydrogen evolution reaction and they act essentially as cathodic inhibitors. The effect of temperature on the corrosion behaviour of mild steel in 1M HCl without and with the bipyrazoles at 10–3M was studied in the temperature range from 298° to 343°K. EIS measurements show the increase of the transfer resistance with the inhibitor concentration.

Details

Anti-Corrosion Methods and Materials, vol. 49 no. 3
Type: Research Article
ISSN: 0003-5599

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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 10−3 M. 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: 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

Keywords

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Article
Publication date: 1 May 2006

Maryam Ehteshamzadeh, Taghi Shahrabi and Mirghasem Hosseini

In this paper, the main aim is to study the synergistic effects of alkanethiols upon inhibition of Schiff bases, N,N′‐ethylen‐bis and N,N′‐ortho‐phenylen‐bis in 0.5 M…

Abstract

Purpose

In this paper, the main aim is to study the synergistic effects of alkanethiols upon inhibition of Schiff bases, N,N′‐ethylen‐bis and N,N′‐ortho‐phenylen‐bis in 0.5 M sulphuric acid solutions.

Design/methodology/approach

Measurements were carried out in a three‐electrode cell assembly connected to the corrosion measurement system using software for Tafel polarization. Impedance measurements were carried out at open circuit potential using an electrochemical interface and frequency response analyzer at frequencies from 100 kHz to 10 MHz.

Findings

Results obtained revealed that at high concentrations, each of the investigated Schiff bases and 1‐dodecanethiol (DT) were good inhibitors when added separately to the corrosive media. The decrease in corrosion rate was associated with an increase in their concentrations. It was found that the presence of DT together with Schiff bases in corrosive medium increased inhibition effect, especially at low concentrations. Synergistic effect is discussed from viewpoint of their co‐adsorption. The adsorption of combined inhibitors was found to follow Langmuir isotherm. Thermodynamic calculations revealed that adsorption of combined inhibitors had a physical nature.

Research limitations/implications

In order to improve further the performance of Schiff bases and identifying their synergistic effects with other additives it is suggested that some more researches on other Schiff bases with other alkanethiol molecules must be done.

Practical implications

The results of this paper can be used for acid cleaning of carbon steel in which suitable inhibitor systems with the highest efficiency is required.

Originality/value

This paper reveals that the presence of DT molecules in solution encourage the adsorption of Schiff bases by facilitating the electrostatic co‐adsorption of Schiff base molecules through a synergistic effect.

Details

Anti-Corrosion Methods and Materials, vol. 53 no. 3
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 27 March 2007

Mobin Salasi, Taghi Shahrabi and Emad Roayaei

To study and compare the inhibition effects of eco‐friendly inhibitors of sodium silicate and 1‐hydroxyethylidene 1,1 diphosphonic acid (HEDP) in corrosion control and…

Abstract

Purpose

To study and compare the inhibition effects of eco‐friendly inhibitors of sodium silicate and 1‐hydroxyethylidene 1,1 diphosphonic acid (HEDP) in corrosion control and prevention of soft water discolouration (red water) in carbon steel pipelines.

Design/methodology/approach

Electrochemical impedance and Tafel polarization measurements were used to study corrosion inhibition properties. The experiments were carried out under different concentration ratios of inhibitors. Different hydrodynamic conditions were applied to simulate pipeline fluid flow. Scanning electron microscopy (SEM) and EDAX analysis were used for surface studies.

Findings

It was observed that corrosion inhibitor combinations under static conditions showed synergistic effects at low concentrations. The inhibition efficiency and synergistic behaviours of inhibitors were enhanced as the electrolyte turbulence was increased. In addition, the inhibitor concentration value required to reach maximum inhibition decreased. It was found that at 20 ppm sodium silicate and 5 ppm HEDP, co‐inhibition efficiencies increased significantly to more than 90 per cent and the corrosion rate decreased far below 1 mpy as the electrode rotational speed was increased. Surface studies using SEM revealed the formation of a compact and uniform film of co‐inhibitors.

Practical implications

The results of this paper can be used for the development of effective, non‐toxic and economically attractive corrosion inhibitor formulations for soft water transmission pipelines.

Originality/value

The observed synergistic behaviour can be due to the incorporation of the silicate gel‐like network through organic phosphorous bonds. The hydrodynamic condition of the electrolyte leads to enhancement of inhibition efficiency, which indicates that the corrosion inhibition was mass transfer controlled.

Details

Anti-Corrosion Methods and Materials, vol. 54 no. 2
Type: Research Article
ISSN: 0003-5599

Keywords

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Article
Publication date: 19 December 2017

Fairouz Badaj and Bouchra Radi

The main purpose of the study is to examine the willingness of Moroccan small- and medium-sized enterprises (SMEs) to adopt profit and loss sharing (PLS) method of finance…

Abstract

Purpose

The main purpose of the study is to examine the willingness of Moroccan small- and medium-sized enterprises (SMEs) to adopt profit and loss sharing (PLS) method of finance and the factors that may influence their decision.

Design/methodology/approach

The research model is based on the decomposed theory of planned behaviour (DTPB). A total of 340 questionnaires were randomly distributed to SMEs’ owner-managers, out of which 177 were collected and only 153 were valid for analysis. Factor analysis and partial least squares regression were subsequently applied.

Findings

The results showed that cost, loss of control, constrained access to conventional debt, financial suitability, stage of development as well as religious beliefs have a significant impact on the SMEs’ attitude towards PLS modes. Likewise, normative belief was also found to have a significant influence on subjective norm, by particular reference to the family, financial external consultants and internal managers, as the main referent groups. In addition, finally, attitude and perceived behavioural control were found to have a significant impact on the intention to adopt PLS financing by Moroccan SMEs.

Research limitations/implications

The sample is not representative; hence, the findings cannot be generalized to all Moroccan SMEs. Furthermore, the variables and dimensions used are not exhaustive. With regard to implications, the study confirms the applicability of the DTPB to SME financing questions. Moreover, this study provides great indications to the practitioners, investors, policy makers and regulators on the perception of the Moroccan entrepreneurs, which should be taken into consideration to establish the necessary strategies to attract them.

Originality/value

This paper verifies the applicability of the DTPB in another area, that is, adoption of PLS instruments and contributes to explain the entrepreneurs’ perceptions towards theses modes of financing.

Details

International Journal of Islamic and Middle Eastern Finance and Management, vol. 11 no. 2
Type: Research Article
ISSN: 1753-8394

Keywords

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