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Article
Publication date: 15 March 2013

Jiayuan Hu, Shun‐an Cao and Jianli Xie

The purpose of this paper is to explore the long‐term corrosion behavior of carbon steel in 3% NaCl solution and evaluate the effect of rust layer on the corrosion process.

Abstract

Purpose

The purpose of this paper is to explore the long‐term corrosion behavior of carbon steel in 3% NaCl solution and evaluate the effect of rust layer on the corrosion process.

Design/methodology/approach

The corrosion behavior of rusted carbon steel in 3% NaCl solution was studied by means of infrared spectroscopy (IR) and electrochemical impedance spectroscopy (EIS).

Findings

The results indicated that the corrosion of carbon steel was affected by chloride ion in initial immersion and then controlled by the rust layer. The rust layer consisted of a thin outer layer (γ‐FeOOH layer) and a thick inner layer (Fe3O4 layer). The outer rust layer facilitated the cathodic process via reduction of γ‐FeOOH, while the inner rust layer provided a large cathode area and oxygen could be reduced on its surface. As a result, the corrosion rate of carbon steel was determined by the limiting diffusion rate of oxygen and stabilized at a high value.

Originality/value

The corrosion model of rusted carbon steel in 3% NaCl solution was established. It is probable that the iron rust in all slightly acidic water with low alkalinity can promote the corrosion process via reduction of γ‐FeOOH. Anti‐corrosion measures for iron in this type of solutions should be aimed to reduce the promoting effect of rust layer on the metal corrosion. The NaCl solution prepared from tap water is more suitable for the substitution of artificial water than that prepared from deionized water.

Details

Anti-Corrosion Methods and Materials, vol. 60 no. 2
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 29 April 2014

Jiayuan Hu, Shun-an Cao, Li Yin and Yang Gao

The purpose of this study was to investigate the corrosion of rusted carbon steel in dilute NaCl solution, with the purpose of exploring the effect of the rust layer on metal…

Abstract

Purpose

The purpose of this study was to investigate the corrosion of rusted carbon steel in dilute NaCl solution, with the purpose of exploring the effect of the rust layer on metal corrosion and establishing a corrosion model for rusted iron.

Design/methodology/approach

The corrosion behavior of rusted carbon steel in dilute NaCl solution was studied by means of weight-loss determinations, scanning electron microscopy, Raman spectrometry and electrochemical techniques.

Findings

The results indicated that carbon steel had a similar corrosion behavior in all three NaCl solutions. The iron rust, which consisted of a thin γ-FeOOH layer and a thick Fe3O4 layer, can facilitate the corrosion process of carbon steel via reduction of γ-FeOOH and the large area cathode of Fe3O4. Hence, the corrosion rate of carbon steel was accelerated significantly and finally was determined by the limiting diffusion rate of oxygen.

Originality/value

A corrosion model of rusted carbon steel was established, suggesting that iron rust formed in all slightly acidic waters with low alkalinity probably promotes the corrosion of carbon steel. Anti-corrosion measures for iron in this type of solution, such as desalination water, should be aimed to reduce the promotional effect of the rust layer on metal corrosion.

Details

Anti-Corrosion Methods and Materials, vol. 61 no. 3
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 3 September 2019

Yong Zhou, Pei Zhang, Jinping Xiong and Fuan Yan

A chromate conversion coating was prepared on the surface of bare AA2024 aluminum alloy by direct immersion in the chromating treatment bath, and the corrosion behavior of…

Abstract

Purpose

A chromate conversion coating was prepared on the surface of bare AA2024 aluminum alloy by direct immersion in the chromating treatment bath, and the corrosion behavior of chromated AA2024 aluminum alloy in 3.5 per cent NaCl solution was studied by electrochemical measurement and microstructural observation.

Design/methodology/approach

According to the polarization curve test and the scanning electron microscope observation, the corrosion evolution of chromated AA2024 in 3.5 per cent NaCl solution was divided into the following three stages: coating failure, pitting corrosion and intergranular corrosion (IGC).

Findings

In the first stage, the chromate coating degraded gradually due to the combined action of chloride anions and water molecules, resulting in the complete exposure of AA2024 substrate to 3.5 per cent NaCl solution. Subsequently, in the second stage, chloride anions adsorbed at the sites of θ phase (Al2Cu) and S phase (Al2CuMg) on the AA2024 surface preferentially, and some corrosion pits initiated at the above two sites and propagated towards the deep of crystal grains. However, the propagation of a pit terminated when the pit front arrived at the adjacent grain boundary, where the initiation of IGC occurred.

Originality/value

Finally, in the third stage, the corrosion proceeded along the continuous grain boundary net and penetrated the internal of AA2024 substrate, resulting in the propagation of IGC. The related corrosion mechanisms for the bare and the chromated AA2024 were also discussed.

Details

Anti-Corrosion Methods and Materials, vol. 66 no. 6
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 21 September 2018

Yingjun Zhang, Baojie Dou, Yawei Shao, Xue-Jun Cui, Yanqiu Wang, Guozhe Meng and Xiu-Zhou Lin

This paper aim to investigate the influence of PA on the corrosion behavior of carbon steel with blast cleaned or pre-rusted treatments, and interpret the inhibition mechanism of…

Abstract

Purpose

This paper aim to investigate the influence of PA on the corrosion behavior of carbon steel with blast cleaned or pre-rusted treatments, and interpret the inhibition mechanism of PA on the steel with different surface treatments.

Design/methodology/approach

The influence of PA on the corrosion behavior of blast cleaned or rusty steel was investigated by means of electrochemical impedance spectroscopy (EIS). The EIS data were analyzed using the @ZsimpWin commercial software. The morphology and component of steel after immersion were characterized by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), Fourier transformation infrared (FTIR) and X-ray diffractometer (XRD).

Findings

EIS analysis results indicated that PA had good corrosion inhibition for blast cleaned or rusty steel. SEM, EDS, FTIR and XRD further indicated that PA had two main corrosion inhibition processes for the corrosion inhibition of blast cleaned or rusty steel: corrosion dissolution and formation of protective barrier layers.

Originality/value

Most published works focus the attention only toward the effect of corrosion inhibitor for the clean metal surfaces. However, the surface condition of metal sometimes is unsatisfactory in the practical application of corrosion inhibitor, such as existing residual rust. Some studies also have shown that several corrosion inhibitors could be applied on partially rusted substrates. These inhibitors mainly include tannins and phosphoric acid, but not PA. Therefore, the authors investigated the influence of PA on the corrosion behavior of carbon steel with blast cleaned or pre-rusted treatments in this paper.

Details

Anti-Corrosion Methods and Materials, vol. 65 no. 6
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 1 May 2006

Cao Xia and Xu Chunchun

The main purpose of this study was to investigate the effect of chloride on the atmospheric corrosion of cast iron in an atmosphere with sulphur‐bearing pollutants.

Abstract

Purpose

The main purpose of this study was to investigate the effect of chloride on the atmospheric corrosion of cast iron in an atmosphere with sulphur‐bearing pollutants.

Design/methodology/approach

Periodic wet‐dry tests, surface tension tests, electrochemical impedance (EIS) measurements, stereoscopic microscopy, scanning electron microscopy and energy dispersive atomic X‐ray analysis were used to investigate the corrosion processes and products. Weight loss measurements, electrochemical theory, as well as ion adsorption theory and penetration theory were used to explain the corrosion process.

Findings

The experimental results demonstrated that weight loss measurement approximately obeyed the relationship: ΔW=AtB. With addition of NaCl, the value of A decreased, whereas B increased. It is worth noting that NaCl acted as an inhibitor in the HSO3 bearing pollutant during the initial corrosion stage. However, as corrosion continued, the penetration effect of chloride and the different characteristics of the corrosion products tended to dominate the corrosion process, which led to changes of the corrosion rate. Both the EIS measurements and surface tension tests agreed well with the results of weight loss measurements.

Originality/value

The initial corrosion stage showed good agreement with associated surface activity. The paper explains the effect of chloride on the atmospheric corrosion of cast iron in sulphur bearing pollutants from a new viewpoint.

Details

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

Keywords

Article
Publication date: 23 May 2008

A. Amadeh, S.R. Allahkaram, S.R. Hosseini, H. Moradi and A. Abdolhosseini

Application of rare earth (RE) salts as a corrosion inhibitor was first proposed by Goldie and McCarrol in 1984. They showed that, with the addition of 0.001 M of Ce(NO3) or La(NO3

Abstract

Purpose

Application of rare earth (RE) salts as a corrosion inhibitor was first proposed by Goldie and McCarrol in 1984. They showed that, with the addition of 0.001 M of Ce(NO3) or La(NO3) to 3.5% NaCl solution, the inhibition efficiencies were 91 and 82% for carbon steel, respectively. The aim of this paper is to study the inhibition of a mixture of Ce and La cations on the corrosion prevention of St37 carbon steel in aerated NaCl solutions using weight loss, potentiodynamic polarization, open circuit potential and constant potential measurements.

Design/methodology/approach

In this study, St37 steel was used as an experimental sample. The applied inhibitor was a powder mixture of Ce and La oxides with the ratio of Ce/La = 2/1. Each gram of this powder was dissolved in 4 cc acetic acid because of their insolubility in water. Steel samples were polished with 120 to 800 grit SiC polishing papers, deoxidized in 15 per cent HCl, and then ultrasonically cleaned in ethanol. They were degreased in acetone and were dried in a flow of hot air.

Findings

It has been shown that a mixture of RE cations (Ce and La) can be used as a corrosion inhibitor for carbon steel in NaCl containing solutions. The optimum inhibitor concentration was found to be 500 ppm with a maximum inhibition efficiency of 76%. An increase in Cl ion concentration and a rise in temperature from room temperature to 70°C can have an adverse effect on corrosion inhibition efficiency.

Originality/value

The results obtained from various experiments indicated that the mixture of Ce and La cations could be considered as a suitable inhibitor for carbon steel in low to medium chloride‐containing solutions. Owing to their non‐toxic nature, they may be suitable to use in potable water pipelines.

Details

Anti-Corrosion Methods and Materials, vol. 55 no. 3
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 1 November 2006

Abdel Salam Hamdy

To develop new eco‐environmentally friendly surface treatments based on cerate compounds as alternatives to the process involving toxic chromates for the corrosion protection of…

Abstract

Purpose

To develop new eco‐environmentally friendly surface treatments based on cerate compounds as alternatives to the process involving toxic chromates for the corrosion protection of magnesium alloys.

Design/methodology/approach

A treatment process in which a surface was alkaline‐etched prior to ceria treatment is proposed. The process involves cleaning, etching in potassium hydroxide followed by treatment in ceria conversion coatings. The effect of surface preparation prior to ceria treatment on the corrosion resistance of AZ91D in 3.5 per cent NaCl solution was measured using AC impedance spectroscopy and DC polarization techniques. Surface examination was performed by scanning electron microscopy, energy dispersive X‐ray.

Findings

It was shown that the ceria treatment can be used as a localized corrosion inhibitor for alloy AZ91D in NaCl solution. The level of inhibition strongly depended on the cerium concentration. Moreover, ceria treatments improved the pitting corrosion resistance due to the formation of protective oxide films which act as a barrier to oxygen diffusion to the metal surface. According to the EIS and polarization measurements, alkaline etching in KOH is more effective in reducing the pitting corrosion of AZ91D than was HCl. It was shown that surface treatment in alkaline solution (KOH) prior to ceria treatments played an important role in inhibiting the active surface sites, rejecting the chloride ions from the surface and forming uniformly distributed oxide film.

Originality/value

Ceria conversion coatings seem very promising as alternatives to toxic chromating for the corrosion protection of magnesium alloys in NaCl solution.

Details

Anti-Corrosion Methods and Materials, vol. 53 no. 6
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 5 October 2023

Minakshi Koundal, Ajay Kumar Singh and Chhaya Sharma

This paper aims to investigate the eco-friendly neodymium tartrate (NdTar) inhibitor for mild steel in sodium chloride (NaCl) solution.

Abstract

Purpose

This paper aims to investigate the eco-friendly neodymium tartrate (NdTar) inhibitor for mild steel in sodium chloride (NaCl) solution.

Design/methodology/approach

The mild steel 1010 coupon was considered for the current study. Weight loss and the electrochemical methods were used to evaluate the inhibitory effects of neodymium chloride (NdCl3) and NdTar on mild steel in NaCl solution. Scanning electron microscopy, energy-dispersive X-ray analysis and attenuated total reflectance-Fourier transform infrared spectroscopy measurements were carried out to study the morphology and composition of the film, nature of deposits and corrosion products formed in test media on the corroded steel, with the objective of further analyzing the observed behavior of the two inhibitors.

Findings

Of the two, NdTar performs better than NdCl3 because it shields mild steel surfaces for longer. According to the results, when NdCl3 is present in a corrosive solution, the protective film only comprises Nd/Fe oxide/hydroxide/carbonate. However, when neodymium is coupled with the tartrate group (an organic group) and then added to the NaCl solution, the inhibitor film comprises both bimetallic complexes (Fe-Tar-Nd) and metal oxide/hydroxide/carbonate, which results in a more compact film and has higher inhibition efficiency.

Originality/value

This study evaluated the combined effects of inorganic and organic inhibitors with those of an inorganic inhibitor used alone for mild steel in NaCl solution.

Details

Anti-Corrosion Methods and Materials, vol. 70 no. 6
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 17 May 2013

Güray Kılınççeker and Hasan Demir

The purpose of this paper is to investigate the inhibition effect of cysteine on the corrosion behaviour of copper in 3.5% NaCl solution with and without cysteine.

Abstract

Purpose

The purpose of this paper is to investigate the inhibition effect of cysteine on the corrosion behaviour of copper in 3.5% NaCl solution with and without cysteine.

Design/methodology/approach

For this purpose, potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) techniques were used. The surface morphology of the metal sample after exposure to the corrosive medium was investigated by scanning electron microscopy (SEM). The effect of temperature also was studied over the range 298‐328 K. Thermodynamic parameters (ΔG, ΔH and ΔS) were calculated and discussed.

Findings

It was found that cysteine could inhibit the corrosion of copper in 3.5% NaCl solution. Cysteine is an organic corrosion inhibitor for copper, and its molecules are physically adsorbed to form a protective film. Inhibition efficiency increases with decreasing cysteine concentration and the product behaves as an anodic‐type inhibitor.

Research limitations/implications

In this study, the inhibitory effect of cysteine with temperature change was investigated in environments containing 10−2 M cysteine solution at pH 8.5.

Practical implications

It will be possible to replace other inhibitors, with cysteine for copper protection in heating/cooling systems at higher temperatures.

Originality/value

Cysteine acts as an anodic inhibitor especially for copper‐based materials in acidic solution. The interaction between the cysteine molecule and copper in alkaline media has not been investigated in detail. The main objectives of this study was to gain some insight into the protection of copper by cysteine in 3.5% NaCl medium at a pH value of 8.5.

Details

Anti-Corrosion Methods and Materials, vol. 60 no. 3
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 11 September 2009

Jianfei Yu, Quanfen Feng and Yafei Yu

The purpose of this paper is to study the corrosion behavior of copper in 3.5 percent NaCl solutions with and without 3‐amino‐5‐mercapto‐1,2,4‐triazole (3‐AMT).

Abstract

Purpose

The purpose of this paper is to study the corrosion behavior of copper in 3.5 percent NaCl solutions with and without 3‐amino‐5‐mercapto‐1,2,4‐triazole (3‐AMT).

Design/methodology/approach

Weight‐loss measurement, potentiodynamic polarization, and electrochemical impedance spectroscopy are applied to study the corrosion behavior of copper in the absence and presence of different concentrations of 3‐AMT under the influence of various experimental conditions.

Findings

The results show that inhibition efficiency (IE) increases with increasing the immersion time in the presence of 1.0×10−4 mol/l 3‐AMT and the IE% maintains about 94 percent during the studied inhibitor concentration of 5.0×103 mol/l. The Tafel polarization studies indicate that the IE% increases with increasing concentration of 3‐AMT, and the compound was a mixed inhibitor. The adsorption of 3‐AMT on the surface on copper has been found to obey the Langmuir adsorption isotherm, and the values of free energy of adsorption are calculated. 3‐AMT is chemically adsorbed on the copper surface.

Originality/value

The results of this paper can be used for reducing corrosion rates of copper in which a suitable inhibitor with the highest efficiencies is required in chloride solutions.

Details

Anti-Corrosion Methods and Materials, vol. 56 no. 5
Type: Research Article
ISSN: 0003-5599

Keywords

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