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Article
Publication date: 17 August 2018

Fahimeh Ansari, Reza Naderi and Fahimeh Rafiaei

This paper aims to access the protective function of hybrid sol-gel coatings deposited on 304L stainless steel substrate in silane solutions containing a mixture of…

Abstract

Propose

This paper aims to access the protective function of hybrid sol-gel coatings deposited on 304L stainless steel substrate in silane solutions containing a mixture of tetraethoxysilane, methyltriethoxysilane and glycidyloxypropyltrimethoxysilane with different pH values during various immersion periods.

Design/methodology/approach

The 304L stainless steels coated through 10 and 30 s of immersion in the silane solutions with pH values of 2.1 and 2.8 were exposed to NaCl solution. The corrosion resistance of the coated substrates was studied through taking advantage of electrochemical noise method as well as atomic force microscopy (AFM), water contact angle and field emission-type scanning electron microscopy (FESEM) surface analysis.

Findings

The electrochemical current noise, PSD (I) plot, noise resistance and characteristic charge as parameters extracted from electrochemical noise method indicated the superiority of eco-friendly silane coating deposited on the substrate surface during 10 s exposure to the solution, due to the film uniformity and homogeneity as confirmed by FESEM and AFM. Moreover, immersion of the stainless steel in the silane solution with pH 2.1, characterized by higher hydrolysis ratio, led to more effective corrosion control in the NaCl electrolyte according to the results of electrochemical noise and FTIR measurements.

Research limitations/implications

The noise resistance and characteristic charge as electrochemical noise parameters were only used in this research to evaluate the protective behavior of the water-based silane sol-gel coatings. Future studies should examine the correlation between electrochemical noise data and the parameters extracted from other electrochemical methods, e.g. electrochemical impedance spectroscopy.

Practical implications

The data obtained in this research may provide an effective approach based on electrochemical noise method to screen the silane sol-gel coatings for protection of metallic substrates against corrosion.

Originality/value

According to the literature, no report can be found studying the effect of immersion time on a silane solution, including glycidyloxypropyltrimethoxysilane, tetraethoxysilane and methyltriethoxysilane, as well as the silane solution pH on the corrosion resistance of 304L stainless steel in NaCl solution through electrochemical noise method.

Article
Publication date: 20 March 2009

Mehdi Attarchi, Mahyar Mazloumi, S.K. Sadrnezhaad, A. Jafari and M. Asadi

The purpose of this paper is to evaluate advanced mathematical electrochemical noise analysis (ENA) as a way of corrosion monitoring for carbon steel.

Abstract

Purpose

The purpose of this paper is to evaluate advanced mathematical electrochemical noise analysis (ENA) as a way of corrosion monitoring for carbon steel.

Design/methodology/approach

The electrochemical potential/current noise was recorded simultaneously with a working‐reference‐working electrode set up and the processing of data was performed through fast Fourier transformation (FFT) and wavelet transformation (WT) routes. The formation and rupture of carbonate films on St37 steel electrodes in a 0.5 M sodium bicarbonate electrolyte was studied for 20 h utilizing an electrochemical noise approach.

Findings

Although the slope of mid‐range of noise impedance exhibited a mechanistic style, and increased with film formation and decreased with film rupture, FFT of potential noise was more sensitive to film formation and rupture. WT of potential noise depicted that ν=1.41 × 10−2 Hz was the boundary frequency in the film formation. At frequencies higher than the mentioned limit, the fraction of distributed potential decreased with time. However, the opposite behavior was observed during the rupture of the film.

Originality/value

The preliminary results show that the proposed novel electrochemical method, wavelet and FFT ENA, is very able to monitor the corrosion behavior of carbon steel corrosion in carbonate media.

Details

Anti-Corrosion Methods and Materials, vol. 56 no. 2
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 18 January 2023

Zexing Ren, Qiushi Li, Xiaorui Yang and Jihui Wang

The purpose of this paper is to identify corrosion types and corrosion transitions by a novel electrochemical noise analysis method based on Adaboost.

Abstract

Purpose

The purpose of this paper is to identify corrosion types and corrosion transitions by a novel electrochemical noise analysis method based on Adaboost.

Design/methodology/approach

The corrosion behavior of Q235 steel was investigated in typical passivation, uniform corrosion and pitting solution by electrochemical noise. Nine feature parameters were extracted from the electrochemical noise data based on statistical analysis and shot noise theory. The feature parameters were analysis by Adaboost to train model and identify corrosion types. The trained Adaboost model was used to identify corrosion type transitions.

Findings

Adaboost algorithm can accurately identify the corrosion type, and the accuracy rate is 99.25%. The identification results of Adaboost for the corrosion type are consistent with corroded morphology analysis. Compared with other machine learning, Adaboost can identify corrosion types more accurately. For corrosion type transition, Adaboost can effectively identify the transition from passivation to uniform corrosion and from passivation to pitting corrosion consistent with corroded morphology analysis.

Originality/value

Adaboost is a suitable method for prediction of corrosion type and transitions. Adaboost can establish the classification model of metal corrosion, which can more conveniently and accurately explore the corrosion types. Adaboost provides important reference for corrosion prediction and protection.

Details

Anti-Corrosion Methods and Materials, vol. 70 no. 2
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 13 September 2011

Reza Moshrefi, Mohammad Ghassem Mahjani, Ali Ehsani and Majid Jafarian

This paper aims to investigate the galvanic corrosion of titanium/L 316 stainless steel, by electrochemical noise (EN), electrochemical impedance spectroscopy (EIS), and…

1037

Abstract

Purpose

This paper aims to investigate the galvanic corrosion of titanium/L 316 stainless steel, by electrochemical noise (EN), electrochemical impedance spectroscopy (EIS), and anode/cathode area ratio effect on the galvanic behavior of the couple.

Design/methodology/approach

The EN measurement was employed to examine effects of anode to cathode area ratio on the galvanic corrosion behavior between stainless steel L 316 and titanium in artificial seawater. Current noise and potential noise were monitored simultaneously using a three‐electrode configuration under open‐circuit condition. The noise resistance was evaluated as the ratio of the standard deviation of the potential to that of the current noise after removing the DC component. The time‐series noise patterns were transformed into frequency domain by fast Fourier transformation and then their power spectrum densities (PSDs) at specified frequency were determined and compared with the EIS and polarization results.

Findings

The EN, EIS and polarization results were in agreement. Galvanic corrosion density increase and galvanic potential moved slowly to negative direction with decrease in anode/cathode area ratio. The results showed that the slope of PSD of the current (i.e the “roll off”) was rising slowly where the anode/cathode area ratio was declined. The relationship between polarization resistance (Rp) and noise resistance (Rn) was investigated. Rt was determined by EIS for samples, and its value compared with Rp and Rn. The result indicates that galvanic corrosion has an inversely relation with anode/cathode area ratio that exposed to aggressive environment.

Originality/value

This paper presents the application of noise analysis to demonstrate galvanic corrosion and the effect of area ratio anode/cathode on current density and galvanic potential.

Details

Anti-Corrosion Methods and Materials, vol. 58 no. 5
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 27 December 2022

Yesen Zhu, Zhe Liu, Zhenbo Qin, Mengyang Hou, Taoyong Hu and Quan Yuan

The purpose of this paper is to study the cavitation erosion stages of AA5083 by electrochemical noise (EN).

Abstract

Purpose

The purpose of this paper is to study the cavitation erosion stages of AA5083 by electrochemical noise (EN).

Design/methodology/approach

EN technology including noise resistance and fast Fourier transform were used to characterize the electrochemical process during the cavitation erosion process.

Findings

AA5083 suffers from uniform corrosion during the cavitation erosion process. The whole cavitation erosion process can be divided into three stages: incubation stage, acceleration stage and steady-state stage. EN signals showed obvious differences in different stages of cavitation erosion.

Originality/value

EN technique is a suitable method that can be used to study cavitation erosion mechanism and identify cavitation erosion stages.

Details

Anti-Corrosion Methods and Materials, vol. 70 no. 2
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 27 June 2008

Mohammad Ghassem Mahjani, Mohammad Sabzali, Majid Jafarian and Jaber Neshati

The purpose of this paper is to investigate the effects of inorganic inhibitors on the corrosion rate of aluminum alloy using the electrochemical noise (EN) analysis and…

1063

Abstract

Purpose

The purpose of this paper is to investigate the effects of inorganic inhibitors on the corrosion rate of aluminum alloy using the electrochemical noise (EN) analysis and electrochemical impedance spectroscopy (EIS) techniques.

Design/methodology/approach

EN and EIS measurements were employed to study the corrosion behavior of aluminum alloy in Na2SO4(0.50 M)/NaCl(0.20 M) solution in presence of inorganic inhibitors. The time‐series noise patterns were transformed into the frequency domain using fast Fourier transformation, and then their power spectrum densities (PSDs) at specified frequencies were determined and compared with the EIS and polarization results.

Findings

The EN, EIS and polarization results were in agreement. The inhibitive effect of the anions decreased in the order: CrO42−>Cr2O72−>NO3>WO42−>MoO42−>NO2. The results showed that the slope of PSD of the current (i.e. the “roll off”) was less where inhibition efficiency was greater. The spectral noise impedance and the modulus of the impedance recorded using impedance spectroscopy showed good agreement.

Originality/value

This paper provides useful information relative to corrosion inhibition efficiency of the sodium and potassium salts using EN analysis technique.

Details

Anti-Corrosion Methods and Materials, vol. 55 no. 4
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 4 September 2020

Jian Song, Zhiming Gao, Chenxi Liu and Wenbin Hu

This paper aims to study the effect of flow rate (0.42∼2.09 m/s) on the corrosion behavior of WB36CN1 steel pipe in the simulated secondary circuit water environment (170°C, 6…

Abstract

Purpose

This paper aims to study the effect of flow rate (0.42∼2.09 m/s) on the corrosion behavior of WB36CN1 steel pipe in the simulated secondary circuit water environment (170°C, 6 mg/L ethanolamine + 100 µg/L NaCl), for which an autoclave was used to simulate the secondary circuit environment for carrying out related experiments.

Design/methodology/approach

The corrosion behaviors were studied by electrochemical methods, morphological observations and elemental analysis.

Findings

As flow rate increases, the amplitude of the current noise fluctuates increased, noise resistance Rn and spectral noise resistance Rsn decreased, the shear stress on the surface of WB36CN1 steel increases, the oxygen content on the surface decreases, the roughness becomes smaller. Meanwhile, the energy of energy distribution plot is concentrated at high frequencies under the three flow conditions, the slopes of current power spectral density curve approach 0 db/decade. This means that the oxide on the surface becomes less and corrosion rate increases with increasing flow rate. The corrosion type of WB36CN1 steel was uniform corrosion; the degree of uniform corrosion is higher at high flow rate.

Originality/value

The effect of flow rate on the corrosion behavior of WB36CN1 steel pipe in the secondary circuit water environment was studied by using electrochemical methods in the laboratory. The effect mechanism of flow rate for corrosion behavior was obtained.

Details

Anti-Corrosion Methods and Materials, vol. 67 no. 5
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 12 September 2008

Saeed Reza Allahkaram and Mehdi Khodayari

The aim of this paper is to show that the use of energy distribution plot (EDP), usually employed by researchers to characterize the behavior of electrochemical signals in the…

Abstract

Purpose

The aim of this paper is to show that the use of energy distribution plot (EDP), usually employed by researchers to characterize the behavior of electrochemical signals in the framework of wavelet transform, could provide better understanding of the electrochemical behavior of a corroding surface if used along with the plot that is obtained from the standard deviation (SD) of partial signals (SDPS). A partial signal (PS) is obtained by limiting the inverse discrete wavelet transform to one crystal, and hence an SDPS is obtained by computing the SD of the corresponding PS.

Design/methodology/approach

The electrochemical current signals, obtained from two identical working electrodes (carbon steel electrodes) exposed to simulated concrete pore solution, sparged simultaneously with SO2 and CO2 were studied using wavelet transforms.

Findings

The results show two steps of passive oxide layer formation: formation of defective passive oxide layer, and strengthening of the passive oxide layer. The passive oxide layer breakdown where CO2 as well as SO2 are involved occurred at a pH of approximately 11. Both the EDP and SDPS plots should be used, simultaneously, to characterize the processes occurring on the surfaces of the exposed electrodes.

Practical implications

The results that were obtained can be regarded as the basis for better understanding and improvement of the noise analysis method.

Originality/value

This paper studies the corrosion behavior of carbon steel rebar before and after the simultaneous introduction of CO2 and SO2 gases in simulated pore solution, using EDP and SDPS plots obtained from the electrochemical current signals at different pH values.

Details

Anti-Corrosion Methods and Materials, vol. 55 no. 5
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 4 November 2022

Quan Yuan, Ning Li, Yujie Li and Junhua Hao

The purpose of this paper is to study the corrosion behavior of 316L stainless steel under cavitation condition in simulated seawater.

Abstract

Purpose

The purpose of this paper is to study the corrosion behavior of 316L stainless steel under cavitation condition in simulated seawater.

Design/methodology/approach

Electrochemical impedance spectroscopy and electrochemical noise analyses are used to characterize the electrochemical process during the cavitation erosion process.

Findings

Because of good corrosion resistance of this material, mechanical damage is the main cause of cavitation erosion. The alloy surface is in active dissolution state during the cavitation erosion process, and the corrosion rate is accelerated as time prolongs which is verified by electrochemical results.

Originality/value

Electrochemical noise is an effective way to study the corrosion under cavitation erosion process.

Details

Anti-Corrosion Methods and Materials, vol. 70 no. 1
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 30 April 2020

Xiaohua Li, Yi Shao, Weixing Miao, Yongchang Liu, Zhiming Gao and Chenxi Liu

The purpose of this paper is to focus on the galvanic corrosion behaviors of the low-carbon ferritic stainless steel electrical resistance welding (ERW) joint in the simulated…

Abstract

Purpose

The purpose of this paper is to focus on the galvanic corrosion behaviors of the low-carbon ferritic stainless steel electrical resistance welding (ERW) joint in the simulated seawater.

Design/methodology/approach

The electrochemical methods such as electrochemical noise, galvanic current and TOEFL polarization curve tests were used to study the galvanic corrosion behaviors of ERW joints of low-carbon ferritic stainless steel in simulated seawater. On this basis, a reliable accelerated corrosion method was developed.

Findings

The corrosion type of the base metal and joint is the typical local corrosion. The order of corrosion resistance from strong to weak is: weld zone > base metal > low-temperature heat-affected zone (HAZ) > high-temperature HAZ. The results of constant current-constant potential accelerated corrosion test show that after constant current-constant potential accelerated corrosion, the joints present a typical groove corrosion pattern. The groove initiating area is located in the HAZ, and the corrosion degree in the weld zone is relatively light, which is consistent with the electrochemical test results.

Originality/value

This paper has clarified the galvanic corrosion behaviors of low-carbon ferritic stainless steel ERW joints. Moreover, a reliable accelerated corrosion method for the low-carbon ferritic stainless steel ERW joint has been developed.

Details

Anti-Corrosion Methods and Materials, vol. 67 no. 3
Type: Research Article
ISSN: 0003-5599

Keywords

1 – 10 of 442