Peyman Taheri, Mahmood Aliofkhazraei, Changiz Dehghanian and Alireza Sabour Rouhaghdam
Plasma electrolytic saturation (PES) treatments were applied on the surface of AISI H13 steel and corrosion resistance of the treated samples was investigated using…
Abstract
Purpose
Plasma electrolytic saturation (PES) treatments were applied on the surface of AISI H13 steel and corrosion resistance of the treated samples was investigated using electrochemical test methods. The aim was to obtain optimal corrosion resistance of the differently treated samples.
Design/methodology/approach
Nitrocarburized and boride layers were produced on AISI H13 steel by the means of the PES technique. Different experimental parameters during each treatment provided different microstructural and electrochemical properties. The techniques used in the present investigation included X‐ray diffraction, SEM, potentiodynamic polarization measurements and electrochemical impedance spectroscopy (EIS).
Findings
The plasma electrolytic nitrocarburising coating was characterized by lower integrity than a PEB coating. All PES coated steels had a noble electrochemical behavior compared to the untreated steel. Different nano‐structures and morphologies obtained by different experimental parameters produced different electrochemical behaviors.
Practical implications
The results obtained in this research into PES techniques can be used wherever good corrosion resistance with the highest efficiency is required.
Originality/value
The speed of treatment by plasma electrolytic saturation techniques makes this method very suitable for industrial production of components.
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Vahid Afshari and Changiz Dehghanian
The purpose of this paper is to demonstrate the effect of grain‐size reduction on the stability of passive films formed on pure iron. Possible mechanisms capable of their…
Abstract
Purpose
The purpose of this paper is to demonstrate the effect of grain‐size reduction on the stability of passive films formed on pure iron. Possible mechanisms capable of their improvement are discussed.
Design/methodology/approach
Nanocrystalline iron was produced by pulse electrodeposition using a citric acid bath. The grain size of the nanocrystalline surface was analyzed by X‐ray diffractometry and atomic force microscopy. The tests were carried out in 95‐97 percent H2SO4 aqueous solution. The stability of the passive films was investigated using Tafel polarization curves and electrochemical impedance spectroscopy measurements.
Findings
The corrosion resistance of Fe in concentrated sulfuric acid solution increased as the grain size decreased from microcrystalline to nanocrystalline. The decreased passive current density of nanocrystalline Fe may be due to the more rapid formation of continuous passive films at surface crystalline defects, compared with coarse‐grained Fe structures.
Originality/value
The behavior of passive film growth and corrosion is considered in terms of excess free energy caused by the nanocrystalline surface.
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A.A. Khalilitabas, C. Dehghanian and M. Aliofkhazraei
The purpose of this paper is to assess the effect of rubber on the durability and corrosion resistance of steel‐reinforced concrete by measuring the permeability, water…
Abstract
Purpose
The purpose of this paper is to assess the effect of rubber on the durability and corrosion resistance of steel‐reinforced concrete by measuring the permeability, water absorption, corrosion potential, linear polarization resistance and AC impedance during 150 days immersion in NaCl solution.
Design/methodology/approach
Permeability, water absorption, corrosion potential, linear polarization resistance and AC impedance during 150 days immersion in NaCl solution have been measured. It was observed that the water permeability of rubberized concrete decreased with the addition of rubber. Scanning electron microscopy micrographs were used to study the bulk of rubberized concrete and it was shown that the interfacial zones of cement/rubber had an important effect on water permeability. The corrosion behavior of this concrete was investigated in the chloride solution.
Findings
It was observed that optimum corrosion resistance was obtained with low rubber contents.
Practical implications
The research results can be used for the fabrication of concrete modified with waste tire material.
Originality/value
The paper describes a method suitable for fabrication of concrete modified with tire waste, especially from an economic standpoint.
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Osuani Fyneface Idema, Malik Abdulwahab, Innocent Okechi Arukalam, Ifeyinwa Ekeke, Chigoziri N. Njoku, Chioma Anyiam, Benedict Onyeachu and Emeka Emmanuel Oguzie
Hexavalent chromium has been a benchmark corrosion inhibitor before it was phased out because of its carcinogenic properties. However, because it was phased out, many alternative…
Abstract
Purpose
Hexavalent chromium has been a benchmark corrosion inhibitor before it was phased out because of its carcinogenic properties. However, because it was phased out, many alternative corrosion inhibitors have been introduced but failed to meet the performance of this benchmark inhibitor. Consequently, benzotriazole (BTA) was reported to exhibit chromate-like inhibition performance. Subsequently, Intelli-ion was reported by researchers to exhibit chromate-like performance also with claims of being a unique alternative. This paper aims to review the inhibition performance of these two alternatives. Above all, promotes the unique inhibition performance of Intelli-ion that makes it suitable for application in many sectors.
Design/methodology/approach
In this paper, the corrosion inhibition performances of BTA and Intelli-ion were compared systematically by reviewing some related literatures based on the opinion of the authors.
Findings
Different methodologies for measuring the inhibition performance of BTA showed that it’s an inhibitor of choice. However, the cut edge corrosion performance of Intelli-ion and BTA corrosion inhibitors on galvanized steel of 55% Wt.% Al, 44% Wt.% Zn and 1% Wt.% Si in 5 Wt.% NaCl solution was compared when subjected to scanning vibrating electrode technique (SVET) for 24 h. The results showed faint blue-colored region depicting negative cathodic current density for the Intelli-ion while there was a high-intensity of red-colored region depicting a positive anodic current density for BTA. In other words, the Intelli-ion inhibitor had a better overall cut-edge corrosion inhibition performance than the BTA inhibitor.
Originality/value
This paper compares and further, summarizes the corrosion inhibition performance of Intelli-ion and BTA by evaluating SVET results from the literature. In addition, it serves as an overview and reference for the unique inhibition performance of Intelli-ion when applied in field applications.
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Aboozar Golgoon, Mahmood Aliofkhazraei, Mansoor Toorani, Mohammad Hossein Moradi, Alireza Sabour Rouhaghdam and Masoud Asgari
The low resistance against penetration of water, oxygen and the other corrosive ions through the paths of coating is one the most important problems. So, protective properties of…
Abstract
Purpose
The low resistance against penetration of water, oxygen and the other corrosive ions through the paths of coating is one the most important problems. So, protective properties of coating such as polyester must be promoted. Recently, the use of nanoparticles in the matrix of polymer coating to increase their protection and mechanical properties has been prospering greatly. The purpose of this study is to improve the corrosion resistance of the polyester powder coating with ZnO nanoparticles. The ZnO nanoparticles have been synthesized by hydrothermal method in a microwave. Using polyester – ZnO nanocomposite coating as powder – combining them by ball milling process and coating them by electrostatic process are innovative ideas and have not been used before it.
Design/methodology/approach
Polyester powder as the matrix and ZnO nanoparticles as reinforcing were combined in three different weight percentage (0.5, 1, 2 Wt.%), and they formed polymer nanocomposite by ball milling process. Then, the fabricated nanocomposite powder was applied to the surface of carbon steel using an electrostatic device, and then the coatings were cured in the furnace. The morphology of synthesized zinc oxide nanoparticles was investigated by transmission electron microscope. Also, the morphology of polyester powder and fabricated coatings was studied by scanning electron microscope. The effects of zinc oxide nanoparticles on the corrosion resistance of coated samples were studied by electrochemical impedance spectroscopy (EIS) test at various times (1-90 days) of immersion in 3.5 per cent NaCl electrolyte.
Findings
Scanning electron microscopy (SEM) results reveal that there are no obvious crack and defects in the nanocomposite coatings. In contrast, the pure polyester coatings having many cracks and pores in their structure. According to the EIS results, the corrosion resistance of nanocomposite coating compared to pure coating is higher. The value obtained from EIS test show that corrosion resistance for coating that contains 1 Wt.% nanoparticle was 32,150,000 (Ωcm2), which was six times bigger than that of pure coating. In addition to providing a barrier against diffusion of electrolyte, ZnO nanoparticles act as a corrosion inhibitor and, thus, increases the corrosion resistance. The corrosion resistance of coating containing 0.5 Wt.% nanoparticles was lower as compared to that of 1 Wt.% nanoparticles. The low content of nanoparticles caused partial covering of the porosity of coating which in turn leads to provide weaker barrier properties. The increase in quantity of nanoparticles from 1 to 2 Wt.% also caused a decrease in corrosion resistance which is attributed to the agglomeration of nanoparticles.
Originality/value
The results of this study indicated the significant effect of ZnO nanoparticles on the protective performance and corrosion resistance of the polyester powder coating. Evaluation of coating surface and interface with SEM technique revealed that nanocomposite coating compared with pure polyester coating provided a coating with lower number of pores and with higher quality. The EIS measurements represented that polymeric coating that contains nanoparticles compared to pure coating provides a better corrosion resistance. In addition to providing a barrier against diffusion of electrolyte, ZnO nanoparticles act as a corrosion inhibitor and thus increase the corrosion resistance. The corrosion resistance of coating containing 0.5 Wt.% nanoparticles was lower as compared to that containing 1Wt.% nanoparticles. The low content of nanoparticles caused partial covering of the porosity of coating which in turn leads to provide weaker barrier properties. The increase in quantity of nanoparticles from 1 to 2 Wt.% also caused a decrease in corrosion resistance which is attributed to the agglomeration of nanoparticles.
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Yan Gao, Qiubo Li, Wei Wu, Qiwei Wang, Yizhe Su, Junxi Zhang, Deyuan Lin and Xiaojian Xia
The purpose of this paper is to study the effect of current-carrying condition on the electrochemical process and atmospheric corrosion behavior of the commercial aluminum alloys.
Abstract
Purpose
The purpose of this paper is to study the effect of current-carrying condition on the electrochemical process and atmospheric corrosion behavior of the commercial aluminum alloys.
Design/methodology/approach
Potentiodynamic polarization tests were performed to study the electrochemical process of the aluminum alloys. Salt spray tests and weight loss tests were carried out to study the atmospheric corrosion behavior. The corrosion morphology of the alloys was observed, and the products were analyzed.
Findings
The corrosion process of four aluminum alloys was accelerated in the current-carrying condition. Moreover, the acceleration effect on A2024 and A7075 was much stronger than that on A1050 and A5052. The main factors would be the differences in microstructure and corrosion resistance between these alloys. As the carried current increased, the corrosion rate and corrosion current density of the aluminum alloys gradually increased, with the protection of the corrosion product film decreasing linearly.
Originality/value
This is a recent study on the corrosion behavior of conductors under current-carrying condition, which truly understands the corrosion status of power grid materials. Relevant results provide support for the corrosion protection and safe service of aluminum alloy in power systems.
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This paper aims to report a study of the influence of tungsten carbide (WC) nanoparticles on corrosion resistance properties of electroless nickel–phosphorus (Ni–P) coatings in…
Abstract
Purpose
This paper aims to report a study of the influence of tungsten carbide (WC) nanoparticles on corrosion resistance properties of electroless nickel–phosphorus (Ni–P) coatings in NaCl solution.
Design/methodology/approach
The morphology of Ni–P–WC nanocomposite coatings was observed by scanning electron microscopy (SEM). The anodic polarization curves, electrochemical impedance spectra (EIS) and weight loss measurements were used to study the corrosion resistance properties of Ni–P–WC nanocomposite coatings in NaCl solution.
Findings
The WC nanoparticles content in the coatings increased with the increase of its concentration in the bath, and the WC nanoparticles are uniformly distributed in Ni–P alloy matrix. The results showed that the incorporation of WC nanoparticles elevated the corrosion resistance properties of Ni–P alloy matrix.
Originality/value
This study shows that the corrosion resistance was improved by the addition of WC nanoparticles to the Ni–P alloy matrix.
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This paper aims to investigate the structural, corrosion and the study of tribocorrosion features of the AA7075 aluminum alloy with and without the application of electroless…
Abstract
Purpose
This paper aims to investigate the structural, corrosion and the study of tribocorrosion features of the AA7075 aluminum alloy with and without the application of electroless Ni-P/Ni-B duplex coating with a thickness of approximately 40 microns.
Design/methodology/approach
Surface characterization of the samples was made by structural surveys (light optic microscope, scanning electron microscopic examinations and X-ray diffraction analyses), hardness measurements, corrosion and tribocorrosion tests.
Findings
Results of the experiments showed that upper Ni-B coating deposited on the surface of first Ni-P layer by duplex treatment caused remarkable increment in the hardness, corrosion resistance and tribocorrosion performance as compared to the AA7075 aluminum alloy.
Originality/value
This study can be a practical reference and offers insight into the effects of duplex treating on the increase of hardness, corrosion and tribocorrosion performance.
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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.
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Onur Çomakli, Mustafa Yazici, Tuba Yetim, Fatih Yetim and Ayhan Celik
This paper aims to investigate the structural, tribological and electrochemical properties of Ag2O, ZnO, NiO coatings and Ag2O/ZnO/NiO nanocomposite films deposited on…
Abstract
Purpose
This paper aims to investigate the structural, tribological and electrochemical properties of Ag2O, ZnO, NiO coatings and Ag2O/ZnO/NiO nanocomposite films deposited on commercially pure titanium.
Design/methodology/approach
Ceramic thin films (Ag2O, ZnO, NiO coatings and Ag2O/ZnO/NiO nanocomposite film) were deposited on commercially pure titanium (CP-Ti) substrate. Surface characterization of the uncoated and coated samples was made by structural surveys (scanning electron microscopic examinations and X-ray diffraction analyses), hardness measurements, tribological and corrosion experiments.
Findings
Results were indicated that sol-gel coatings improved the wear and corrosion resistance of CP-Ti, and the best results were seen at the nanocomposite coating. It may be attributed to its small grain size, high surface hardness and high film thickness.
Originality/value
This study can be a practical reference and offers insight into the influence of nanocomposite ceramic films on the increase of hardness, tribological and corrosion performance. Also, the paper displayed a promising approach to produce Ag2O/ZnO/NiO nanocomposite coating on commercially pure titanium implants for biomedical applications.