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Article
Publication date: 1 October 1966

V. Kapali and N. Subramanyan

The performance of commercial aluminium as a sacrificial anode for cathodic protection of mild steel in 0.3% sodium chloride has been studied in alkaline compositions for anolyte…

41

Abstract

The performance of commercial aluminium as a sacrificial anode for cathodic protection of mild steel in 0.3% sodium chloride has been studied in alkaline compositions for anolyte based on slaked lime. The influence of several addition agents has been investigated with a view to suppressing local cell action in the above‐mentioned environment.

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Anti-Corrosion Methods and Materials, vol. 13 no. 10
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 1 November 1965

K. Venu, N. Subramanyan and K.S.G. Doss

In a critical range of concentrations of chloride ions in sodium hydroxide solutions, mild steel can be anodically polarised, but the polarised state cannot be maintained. It is…

46

Abstract

In a critical range of concentrations of chloride ions in sodium hydroxide solutions, mild steel can be anodically polarised, but the polarised state cannot be maintained. It is, however, found that the polarised state can be restored by cutting off the current for a minimum amount of time or by substituting a purely inhibitive solution for the original corrosive solution. The anodic potential accelerates the depassivation caused by chloride ions. It has been observed that cathodic polarisation is only as effective as interruption of the anodic current in restoring the polarised state. The results are discussed in relation to the occurrence of depassivation at a few random spots, and the significance of the results is pointed out from the point of view of the technique for finding out the corrosive or inhibitive character of an environment.

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Anti-Corrosion Methods and Materials, vol. 12 no. 11
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 12 January 2010

A. Elango, V.M. Periasamy, M. Paramasivam and E. Rakesh

The purpose of this paper is to show how to develop inhibition 57S aluminium in 2M NaOH solution.

381

Abstract

Purpose

The purpose of this paper is to show how to develop inhibition 57S aluminium in 2M NaOH solution.

Design/methodology/approach

The approach is used to measure gravimetric and polarization measurements.

Findings

The results of the paper clearly reveal that the 0.2 M ZnO with 700 ppm polyaniline in N‐methyl‐2‐pyrrolidone solution is found to offer inhibition up to 71.2 per cent.

Originality/value

The paper deals with the development of newer inhibitor based on polyaniline. Gravimetric and galvanostatic methods were employed to evaluate inhibition efficiency.

Details

Anti-Corrosion Methods and Materials, vol. 57 no. 1
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 11 January 2008

M.N. Desai, J.D. Talati and N.K. Shah

A survey of technical literature indicates that there is a shortage of excellent corrosion inhibitors for zinc in non‐oxidizing acids, particularly sulphuric acid. This paper aims…

969

Abstract

Purpose

A survey of technical literature indicates that there is a shortage of excellent corrosion inhibitors for zinc in non‐oxidizing acids, particularly sulphuric acid. This paper aims to describe the behaviour of ethylenediamine‐NN′‐dibenzylidene, ethylenediamine‐NN′‐disalicylidene, ethylenediamine‐NN′‐dicinnamylidene, triethylenetetramine tribenzylidene and triethylenetetramine trisalicylidene as corrosion inhibitors for zinc in sulphuric acid solutions. The objective of this research work also is to have an insight into the action mechanism of these inhibitors.

Design/methodology/approach

The effect of the various parameters affecting the action of the above‐mentioned corrosion inhibitors has been studied using weight‐loss data and polarisation measurements. Adsorption data also were utilized.

Findings

The inhibitors showed excellent corrosion inhibition (>99 per cent) at effective inhibitor concentrations. The two salicylidenes were better corrosion inhibitors than were corresponding benzylidenes. It appeared from this study that an efficient inhibitor is characterised by a relatively greater decrease in free energy of adsorption, lower entropy of adsorption and relatively lower heat of adsorption. Basically, these inhibitors were cathodic, as was revealed by polarisation data, and the inhibitors followed Langmuir adsorption isotherm behaviour. In general, the conjoint action of the inhibitor and the cathodic current was synergistic.

Research limitations/implications

Powerful Schiff bases still need to be synthesized so as to be effective at extremely low concentrations. The behaviour with other metals and alloys in diverse media also requires to be investigated.

Originality/value

Very few inhibitors demonstrate such excellent corrosion inhibition of zinc in aggressive corrosive media. Such detailed investigations on corrosion inhibitors are unusual.

Details

Anti-Corrosion Methods and Materials, vol. 55 no. 1
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 1 April 2005

J.D. Talati, M.N. Desai and N.K. Shah

The evaluation of Schiff bases derived from o‐, m‐ and p‐aminophenols and salicylaldehyde as corrosion inhibitors of zinc in sulfuric acid and to study their action mechanism.

819

Abstract

Purpose

The evaluation of Schiff bases derived from o‐, m‐ and p‐aminophenols and salicylaldehyde as corrosion inhibitors of zinc in sulfuric acid and to study their action mechanism.

Design/methodology/approach

The effect of various parameters on the behaviour of these inhibitors has been studied using the weight loss and polarization measurements.

Findings

In general, the ortho isomer was highly effective as a corrosion inhibitor because it formed a chelate with a six‐membered ring and moreover the ortho isomer possessed pronounced electromeric effect. These inhibitors obey the Langmuir adsorption isotherm. The almost constant performance with temperature in the case of ortho and para isomers in 0.5 M sulfuric acid suggested strong adsorption bonds. The thermodynamic parameters suggested that this strong interaction of the inhibitor molecules with the metal surface resulted in spontaneous adsorption. It may be concluded that a good inhibitor is characterised by a relatively greater decrease in free energy of adsorption, lower entropy of adsorption and higher heat of adsorption. Polarization data indicated that all these isomers were predominantly cathodic inhibitors. The conjoint effect of external cathodic current and these inhibitors was either synergistic or additive.

Research limitations/implications

Even more powerful Schiff bases need to be synthesised and evaluated as corrosion inhibitors with a number of metals and alloys in diverse media, which may be effective at low concentrations.

Originality/value

Very few inhibitors exhibit such excellent inhibitive effect on zinc in aggressive corrosive media. Rarely do we find such detailed studies.

Details

Anti-Corrosion Methods and Materials, vol. 52 no. 2
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 1 August 1998

K. Madhavan, S. Muralidharan and S. Venkatakrishna Iyer

The influence of thiophenol on the corrosion and hydrogen permeation 1M HCl and 0.SM H2SO4 has weightloss measurements, gasometric studies and other electrochemical techniques…

394

Abstract

The influence of thiophenol on the corrosion and hydrogen permeation 1M HCl and 0.SM H2SO4 has weightloss measurements, gasometric studies and other electrochemical techniques. Thiophenol inhibits the corrosion of mild steel in both the acids, but it is found to be more effective in H2SO4. It behaves predominantly as a cathodic inhibitor. It brings down the permeation current in both the acids, but is more effective in H2SO4. The adsorption of thiophenol on the mild steel surface from both the acids obeys Temkin’s adsorption isotherm.

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Anti-Corrosion Methods and Materials, vol. 45 no. 4
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 1 April 1965

GERMANY Preparing metal surfaces with liquid jets A comparative newcomer among the many conventional methods of surface treatment and finishing is the technique of using liquid…

15

Abstract

GERMANY Preparing metal surfaces with liquid jets A comparative newcomer among the many conventional methods of surface treatment and finishing is the technique of using liquid jets. A method designed to permit multi‐purpose surface treatment in a single series of operations has been developed in Switzerland and is described in Technisclie Zeitschrift für praktische Metalbearbeitung (No. 5, 1964) by O. Burnand, Lausanne.

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Anti-Corrosion Methods and Materials, vol. 12 no. 4
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 1 March 1990

M.N. Moussa, M.M. El‐Tagoury, A.A. Radi and S.M. Hassan

Inhibition of carboxylic acids of aluminium corrosion in hydrochloric acid and sodium hydroxide solutions has been studied using weight‐loss and hydrogen evolution methods. The…

137

Abstract

Inhibition of carboxylic acids of aluminium corrosion in hydrochloric acid and sodium hydroxide solutions has been studied using weight‐loss and hydrogen evolution methods. The order of inhibition action of aromatic acids depends on the number and position of the carboxylic groups and the other substituents in the benzene ring. Increase of the chain length increases the inhibiting power of aliphatic acids. The inhibition efficiency in NaOH is higher than that in HCI solutions. The action of inhibition was discussed in terms of the chemical structure of the inhibitors.

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Anti-Corrosion Methods and Materials, vol. 37 no. 3
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 1 March 1965

The dock gate cable seen in the photograph below is submerged in sea‐water for 12 hours out of every 24. Nine years ago an inspection showed the appearance of rust on the same…

20

Abstract

The dock gate cable seen in the photograph below is submerged in sea‐water for 12 hours out of every 24. Nine years ago an inspection showed the appearance of rust on the same cable and a replacement was considered. However, it was decided to try an application of the anti‐corrosive lubricant Voler V 200 R, a graphited compound made by Revol Ltd. The cable was ‘unlocked’ and impregnated with the compound. In the nine years since, no further trouble has been experienced. Another example of the protection afforded by V 200 R in the marine field is its use on the cables of Arctic survey ships. After treatment with the compound it is claimed that the life of these cables has been quadrupled.

Details

Anti-Corrosion Methods and Materials, vol. 12 no. 3
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 1 August 2004

G. Bereket, A. Pınarbaşı and C. Öğretir

The effect of benzimidazole‐2‐tione and benzoxazole‐2‐tione derivatives on the corrosion of aluminium in 0.1 M HCl has been investigated by a potentiostatic polarisation…

458

Abstract

The effect of benzimidazole‐2‐tione and benzoxazole‐2‐tione derivatives on the corrosion of aluminium in 0.1 M HCl has been investigated by a potentiostatic polarisation technique. Inhibition efficiencies were found to follow the order: benzimidazole‐2‐tione > 5‐methyl benzimidazole‐2‐tione > 5‐chloro benzimidazole‐2‐tione, while that of benzoxazole‐2‐tione derivatives were found to follow the order: 5‐methyl benzoxazole‐2‐tione > benzoxazole‐2‐tione > 5‐chloro benzoxazole‐2‐tione > 5‐nitro benzoxazole‐2‐tione. The inhibitive action of these heterocyclic compounds was mainly due to adsorption on the metal surfaces, which show parallelism with the calculated total negative charge of each of the molecules. Thermodynamic parameters, such as values of free energies of adsorption ΔGads and values of equilibrium constants Kads, were determined. Activation energies Ea, activation enthalpies ΔH* and activation entropies ΔS* were determined from the corrosion currents measured at different temperatures.

Details

Anti-Corrosion Methods and Materials, vol. 51 no. 4
Type: Research Article
ISSN: 0003-5599

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