Search results
1 – 10 of over 1000Abstract
Purpose
This paper aims to focus on an assessment of the electrochemical corrosion performance of bulk NC copper in a variety of corrosion environments.
Design/methodology/approach
The electrochemical corrosion behavior of bulk nanocrystalline (NC) copper prepared by inert gas condensation and in situ warm compress technique was studied by using potentiodynamic polarization and electrochemical impedance spectroscopy tests in de-aerated 0.1 M NaOH solution.
Findings
NC copper exhibited a typical active-passive-transpassive behavior with the formation of duplex passive films, which was qualitatively similar to coarse-grain (CG) copper. Although a compact passive film formed on NC copper surface, the corrosion resistance of NC copper was lower in comparison with CG copper. The increase in corrosion rate for NC copper was mainly attributed to the high activity of surface atoms and intergranular atoms. These atoms led to an enhancement of passive ability and an increase of dissolution rate of passive film in oxygen-deficiency solution. For NC copper, the corrosion resistance decreased as grain size increased in NC range.
Originality/value
The difference in corrosion resistance between bulk NC copper and its CG counterpart is dependent upon the corrosion solution. In a previous work, the potentiodynamic polarization tests revealed that NC copper bulks (grain size 48, 68, 92 nm) had identical corrosion resistance to CG copper bulk in naturally aerated 0.1 M NaOH solution. The results might be related to the dissolved oxygen in the medium.
Details
Keywords
Zhangyu Wu, Hongfa Yu, Haiyan Ma, Bo Da and Yongshan Tan
Coral aggregate seawater concrete (CASC) is a new type of lightweight aggregate concrete that is becoming widely used in reef engineering. To investigate the corrosion behavior of…
Abstract
Purpose
Coral aggregate seawater concrete (CASC) is a new type of lightweight aggregate concrete that is becoming widely used in reef engineering. To investigate the corrosion behavior of different kinds of rebar in CASC exposed to simulated seawater for 0-270 d, the electrochemical techniques, including linear polarization resistance (LPR) technique and the electrochemical impedance spectroscopy (EIS), were used in the present work.
Design/methodology/approach
The electrochemical techniques, including LPR technique and the EIS, were used in the present work.
Findings
Based on the time-varying law of linear polarization curves, self-corrosion potential (Ecorr), polarization resistance (Rp), corrosion current density (Icorr), corrosion rate (i), and the characteristics of EIS diagrams for different types of rebar in CASC, it can be found that the anti-corrosion property of them can be ranked as epoxy resin coated steel > 2205 duplex stainless steel (2205S) > 316 L stainless steel (316 L) > organic coated steel > ordinary steel. Additionally, the linear regression equation between Rp and charge transfer resistance (Rct) was established. Finally, the EIS corrosion standard of rebar was established from the LPR corrosion standard, which provides a direct standard for the EIS technique to determine the condition of rebar in CASC.
Originality/value
The linear regression equation between polarization resistance and charge transfer resistance was established. And the EIS corrosion standard of rebar was established from the LPR corrosion standard, which provides a direct standard for the EIS technique to determine the condition of rebar in CASC.
Details
Keywords
J.F. Flores, B. Valdez S., M. Schorr and J.J. Olaya
To investigate the protective properties of tantalum nitride (TaN) thin films deposited on to various steels immersed in a 3 per cent NaCl solution.
Abstract
Purpose
To investigate the protective properties of tantalum nitride (TaN) thin films deposited on to various steels immersed in a 3 per cent NaCl solution.
Design/methodology/approach
TaN thin films with a thickness of 250 nm were deposited on UNS G10180, UNS S30400 and UNS T11302 steels by means of magnetron sputtering technique. The electrochemical behaviour has been studied in 3 per cent NaCl solution using electrochemical impedance spectroscopy and potentiodynamic polarization. The crystalline structure of the films was investigated by X‐ray diffraction. Surface analysis of the corroded samples was performed using scanning electron microscopy and light optical microscopy. The electrochemical impedance spectra were analysed in the context of equivalent circuit models (ECs).
Findings
The ECs incorporate a charge transfer process representing the TaN film on UNS G10180 steel, two time constants for that deposited on UNS T11302 and diffusion behaviour for the TaN film on UNS S30400 steel. TaN films demonstrate their protection properties, which were evidenced by increase of the electrochemical properties compared with the substrate. The major corrosion damage of coatings is caused by defects, pores, droplets and pinholes that allow the electrolyte penetration through the films.
Practical implications
Corrosion protections of steels by TaN thin films.
Originality/value
The information related to corrosion behaviour of TaN films in a chloride solution is poor. This paper presents not only a completely electrochemical characterization, but also the surface analysis of the corroded samples.
Details
Keywords
Fatemeh Baghaei Ravari, Saeed Mohammadi and Athareh Dadgarinezhad
The purpose of this paper is to investigate how to improve the corrosion inhibition behavior of molybdate‐based inhibitors for mild steel, using organic compounds containing a…
Abstract
Purpose
The purpose of this paper is to investigate how to improve the corrosion inhibition behavior of molybdate‐based inhibitors for mild steel, using organic compounds containing a phenyl ring together with nitrite agent. As picrate contains a phenyl ring together with three substituent nitrite anions, it is used as an organic compound. In this study a new molybdate‐based inhibitor was introduced with the composition of 60 ppm molybdate/40 ppm nitrite/20 ppm picrate. Inhibition efficiency of molybdate alone and with nitrite and picrate on the uniform corrosion of mild steel in stimulated cooling water was assessed.
Design/methodology/approach
The inhibition efficiency of molybdate alone and with nitrite and picrate on the uniform corrosion of mild carbon steel in stimulated cooling water (SCW) was assessed by electrochemical techniques such as potentiodynamic polarization, electrochemical impedance (AC impedance) measurements and weight loss determinations at the room temperature. Studies of electron microscopy included scanning electron microscopy (SEM) photography and X‐Ray energy dispersive (EDS) microanalysis were used.
Findings
The results obtained from the polarization and AC impedance curves were in agreement with those from the corrosion weight loss results. The results indicated that the new inhibitor was as effective as molybdate alone, though at one quarter of the concentration range of molybdate, which is economically favorable.
Originality/value
The paper demonstrates improvement in corrosion inhibition of mild steel in SCW via a blend of molybdate, nitrite and picrate as a new anodic inhibitor.
Details
Keywords
Muhammad Firdaus Mohd Nazeri, Muhamad Zamri Yahaya, Ali Gursel, Fakhrozi Cheani, Mohamad Najmi Masri and Ahmad Azmin Mohamad
The purpose of this paper is to review and examine three of the most common corrosion characterization techniques specifically on Sn-Zn solders. The discussion will highlight the…
Abstract
Purpose
The purpose of this paper is to review and examine three of the most common corrosion characterization techniques specifically on Sn-Zn solders. The discussion will highlight the configurations and recent developments on each of the compiled characterization techniques of potentiodynamic polarization, potentiostatic polarization and electrochemical impedance spectroscopy (EIS).
Design/methodology/approach
The approach will incorporate a literature review of previous works related to the experimental setups and common parameters.
Findings
The potentiostatic polarization, potentiodynamic polarization and EIS were found to provide crucial and vital information on the corrosion properties of Sn-Zn solders. Accordingly, this solder relies heavily on the amount of Zn available because of the inability to produce the intermetallic compound in between the elements. Further, the excellent mechanical properties and low melting temperature of the Sn-Zn solder is undeniable, however, the limitations regarding corrosion resistance present opportunities in furthering research in this field to identify improvements. This is to ensure that the corrosion performance can be aligned with the outstanding mechanical properties. The review also identified and summarized the advantages, recent trends and important findings in this field.
Originality/value
The unique challenges and future research directions regarding corrosion measurement in Sn-Zn solders were shown to highlight the rarely discussed risks and problems in the reliability of lead-free soldering. Many prior reviews have been undertaken of the Sn-Zn system, but limited studies have investigated the corrosive properties. Therefore, this review focuses on the corrosive characterizations of the Sn-Zn alloy system.
Details
Keywords
Jun Wang, Zili Li, Gan Cui, JianGuo Liu, Chuanping Kong, Long Wang, Ge Gao and Jian Guo
The purpose of this paper is to study the corrosion behaviors of X70 steel under direct current (DC) interference at 0-1,200 A/m2 in simulated soil solution.
Abstract
Purpose
The purpose of this paper is to study the corrosion behaviors of X70 steel under direct current (DC) interference at 0-1,200 A/m2 in simulated soil solution.
Design/methodology/approach
The Tafel polarization curves of X70 steel under DC interference were tested using electrochemical method, the corrosion rate was calculated using weight-loss method and the change in steel surface was analyzed by optical microscopy.
Findings
The results showed that E-I polarization curves under 200-1,200 A/m2 interference were linear; with an increase in the DC density, the corrosion potential of X70 steel shifted positively, solution pH after the weight-loss tests increased and corrosion rate increased linearly. A mathematical relationship between polarization resistance Rp and current density was established. Corrosion morphology indicated that pitting corrosion and crevice corrosion occurred on the X70 steel under DC interference in simulated soil solution.
Originality/value
All tests were conducted at a relative higher DC density (200-1,200 A/m2). The linear fitting method is proposed to fit data of Tafel polarization curves under DC interference. This study provides guidelines for safe operation of X70 steel pipelines.
Details
Keywords
Gang Wang, Yue Zhang, Chen Gao, GuangTao Xu and MingHao Zhao
The purpose of this paper is to investigate, the effects of residual stress and microstructure on the corrosion behaviour of carburised 18CrNiMo7-6 steel in a 3.5% NaCl aqueous…
Abstract
Purpose
The purpose of this paper is to investigate, the effects of residual stress and microstructure on the corrosion behaviour of carburised 18CrNiMo7-6 steel in a 3.5% NaCl aqueous solution.
Design/methodology/approach
The electrochemical tests were conducted using an electrochemical workstation with a three-electrode system in a 3.5% NaCl aqueous solution, the residual stress of each working face was measured by a high-speed residual stress analyser, and microstructure of different carburised layers were observed scanning electron microscopy. Finally, the effect of carbon content, microstructure and residual stress on the corrosion behaviour of the steel was discussed.
Findings
The results showed that the residual compressive stress in the carburised layer initially increased and subsequently decreased with increasing depth of the carburised layer, reaching stability in the matrix layer. The electrochemical tests before and after stress reduction showed that the electrochemical impedance and the electrochemical potential increased with the reduction of residual compressive stress.
Originality/value
The residual compressive stress in the carburised layer initially increases and subsequently decreases with increasing carburised layer depth. The electrochemical impedance and the electrochemical potential increased with the reduction of residual compressive stress. The general relationship between electrochemical potential and residual stress was established.
Details
Keywords
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
Keywords
Chhotu Ram, Chhaya Sharma and A K Singh
– This paper aims to report on corrosivity of secondary-stage paper mill effluent and corrosion performance of stainless steels.
Abstract
Purpose
This paper aims to report on corrosivity of secondary-stage paper mill effluent and corrosion performance of stainless steels.
Design/methodology/approach
For this purpose, immersion test and electrochemical polarization tests were conducted in mill and synthetic effluent to evaluate the uniform and localized corrosion.
Findings
Corrosivity of mill effluent has been compared with synthetic and primary-stage effluent of the same mill. It is observed that anions present in them, viz. SO4−, PO34−, NO2− and NO3−, impart inhibition, whereas Cl− and chlorophenols enhance the corrosivity of the effluent. The overall effect of various components was reduction in corrosivity of secondary mill effluent.
Originality/value
These observations can be useful for material selection and helpful in corrosion mitigation in paper mill effluent treatment plants.
Details
Keywords
Dong Liu, ZhenYu Chen and XingPeng Guo
The purpose of this paper is to consider the effect of acetic acid and acetate on the anodic and cathodic reactions of carbon steel present in CO2 corrosion.
Abstract
Purpose
The purpose of this paper is to consider the effect of acetic acid and acetate on the anodic and cathodic reactions of carbon steel present in CO2 corrosion.
Design/methodology/approach
The corrosion behaviour of carbon steel (N80) in CO2‐saturated 1% NaCl solution at 50°C and 0.1 MPa was investigated by using weight‐loss tests, electrochemical methods (polarization curves and electrochemical impedance spectroscopy) and surface analysis (scanning electron microscopy).
Findings
The results indicated that: both HAc and Ac− significantly increased the corrosion rate of carbon steel, and the surface chemical reactions of cathodic reduction were enhanced in the presence of HAc and Ac−. Because adsorbed HAc could be reduced directly in the presence of Ac−, the corrosion rate increased, even though the pH of the solution increased. Ac− played an important role in the anodic dissolution processes, which mainly affects the formation/adsorption of intermediates, and acts to form more soluble corrosion products.
Originality/value
The results of this work clarify the role of acetic acid or acetate in the anodic and cathodic reactions of CO2 corrosion.
Details