scholarly journals Electrochemical and microscopic analysis on corrosion behavior of steel bars in slag/fly ash-cement paste subjected to seawater attack

2021 ◽  
Vol 7 (2) ◽  
pp. 33-55
Author(s):  
Shuai Zou ◽  
◽  
Xiao-Nao Zuo ◽  
Xinagnan Li ◽  
Jianzhuang Xiao ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Reinforced Concrete ◽  
Fly Ash ◽  
Corrosion Behavior ◽  
Cement Paste ◽  
Marine Environment ◽  
Electrochemical Impedance ◽  
Physical Adsorption ◽  
Chloride Diffusion ◽  
Steel Bars

series of corrosion experiments of cement paste-steel bar specimens with different contents of slag and fly ash were performed to investigate the influence of slag/fly ash on the corrosion behavior of steel bars in concrete under seawater. In this investigation, the corrosion behavior of specimen was electrochemically monitored by open-circuit potential (OCP), Tafel polarization (TP) and electrochemical impedance spectra (EIS). Meanwhile, SEM/EDS and XRD were applied to microscopically analyze the microstructure deterioration of materials. Results showed that, replacing cement with slag/fly ash caused a decrease in Ca(OH)2 as well as an increase in C-S-H gel and Friedel's salt in concrete, which can improve the chloride-solidification ability and slow down the chloride diffusion in concrete by both physical adsorption and chemical binding, and thereafter promoting the corrosion resistance of steel bars in concrete in marine environment. Compared to slag, the equal replacing content of fly ash can contribute to a better improving effect on the corrosion resistance of reinforced concrete in marine environment. In this study, a replacement of cement by 20% slag+20% fly ash led to an optimum improving effect on its corrosion resistance. In addition, the results also indicate that the corrosion of reinforced concrete caused by seawater attack does not occur at a uniform rate, but it can firstly maintain a long-term uncorroded state, and then develops rapidly after pitting corrosion occurs.

scholarly journals Influence of Rust Inhibitor on the Corrosion Resistance of Reinforcement in Cement Paste with Chloride

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 606
Author(s):  
Linchun Zhang ◽  
Ailian Zhang ◽  
Ke Li ◽  
Qian Wang ◽  
Junzhe Liu ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Cement Paste ◽  
Photoelectron Spectroscopy ◽  
Electrical Resistance ◽  
Corrosion Properties ◽  
Passivation Film ◽  
Steel Bars ◽  
Assembly Unit ◽  
Chloride Environment ◽  
Rust Inhibitor

The electrical resistance and polarization effect of cement paste containing reinforcement were tested to research the anti-corrosion properties of steel bars in cement paste. Moreover, the microstructure and composition of passivation film and rust on the steel bars were studied. The water–cement ratio of the cement paste in this study was 0.3, with 0.5% NaCl, 1% NaNO2, and 1% Benzotriazole, and an assembly unit of 0.5% NaNO2 + 0.5% Benzotriazole by mass of cement was added to the cement to provide a chloride environment. X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM) were applied to research the composition of the passivation film and the microstructure of the cement paste, respectively. The results indicated that the samples with the assembly unit of 0.5% NaNO2 + 0.5% Benzotriazole showed the highest electrical resistance and polarization electrical resistance, while the specimens with 1.0% Benzotriazole showed the lowest electrical resistance and polarization electrical resistance. Moreover, the passivation film of steel bars weakened with increasing distance from the surface of the steel bars. Therefore, the corrosion of steel bars becomes more serious with increasing distance. Finally, the influence of the rust inhibitor on the corrosion resistance of steel bars in the specimens decreased in the following order: 0.5% NaNO2 + 0.5% Benzotriazole >1.0% NaNO2>1.0% Benzotriazole.

scholarly journals Assessment of nickel titanium and beta titanium corrosion resistance behavior in fluoride and chloride environments

2013 ◽  
Vol 83 (5) ◽  
pp. 864-869 ◽  
Author(s):  
Elisa J. Kassab ◽  
José Ponciano Gomes
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Electrochemical Impedance ◽  
Fluoride Concentration ◽  
Nickel Titanium ◽  
Localized Corrosion ◽  
General Corrosion ◽  
Nacl Solution ◽  
Galvanic Coupling ◽  
Beta Titanium

ABSTRACT Objective: To assess the influence of fluoride concentration on the corrosion behavior of nickel titanium (NiTi) superelastic wire and to compare the corrosion resistance of NiTi with that of beta titanium alloy in physiological solution with and without addition of fluoride. Materials and Methods: NiTi corrosion resistance was investigated through electrochemical impedance spectroscopy and anodic polarization in sodium chloride (NaCl 0.15 M) with and without addition of 0.02 M sodium fluoride (NaF), and the results were compared with those associated with beta titanium. The influence of fluoride concentration on NiTi corrosion behavior was assessed in NaCl (0.15 M) with and without 0.02, 0.04, 0.05, 0.07, and 0.12 M NaF solution. Galvanic corrosion between NiTi and beta titanium were investigated. All samples were characterized by scanning electron microscopy. Results: Polarization resistance decreased when NaF concentration was increased, and, depending on NaF concentration, NiTi can suffer localized or generalized corrosion. In NaCl solution with 0.02 M NaF, NiTi suffer localized corrosion, while beta titanium alloys remained passive. Current values near zero were observed by galvanic coupling of NiTi and beta titanium. Conclusions: There is a decrease in NiTi corrosion resistance in the presence of fluoride. The corrosion behavior of NiTi alloy depends on fluoride concentration. When 0.02 and 0.04 M of NaF were added to the NaCl solution, NiTi presented localized corrosion. When NaF concentration increased to 0.05, 0.07, and 0.12 M, the alloy presented general corrosion. NiTi corrosion resistance behavior is lower than that of beta titanium. Galvanic coupling of these alloys does not increase corrosion rates.

Evaluation of the corrosion behavior of AZ31 magnesium alloy with different protein concentrations

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yucong Ma ◽  
Mohd Talha ◽  
Qi Wang ◽  
Zhonghui Li ◽  
Yuanhua Lin
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Electrochemical Impedance ◽  
Surface Film ◽  
Energy Dispersive Spectrometer ◽  
Inhibitory Effect ◽  
Corrosion Process ◽  
High Concentration ◽  
Content Type ◽  
Atomic Force

Purpose The purpose of this paper is to study systematically the corrosion behavior of AZ31 magnesium (Mg) alloy with different concentrations of bovine serum albumin (BSA) (0, 0.5, 1.0, 1.5, 2.0 and 5.0 g/L). Design/methodology/approach Electrochemical impedance spectroscopy and potential dynamic polarization tests were performed to obtain corrosion parameters. Scanning electrochemical microscopy (SECM) was used to analyze the local electrochemical activity of the surface film. Atomic force microscope (AFM), Scanning electron microscope-Energy dispersive spectrometer and Fourier transform infrared spectroscopy were used to determine the surface morphology and chemical composition of the surface film. Findings Experimental results showed the presence of BSA in a certain concentration range (0 to 2.0 g/L) has a greater inhibitory effect on the corrosion of AZ31, however, the presence of high-concentration BSA (5.0 g/L) would sharply reduce the corrosion resistance. Originality/value When the concentration of BSA is less than 2.0 g/L, the corrosion resistance of AZ31 enhances with the concentration. The adsorption BSA layer will come into being a physical barrier to inhibit the corrosion process. However, high-concentration BSA (5.0 g/L) will chelate with dissolved metal ions (such as Mg and Ni) to form soluble complexes, which increases the roughness of the surface and accelerates the corrosion process.

scholarly journals Improving Sustainability through Corrosion Resistance of Reinforced Concrete by Using a Manufactured Blended Cement and Fly Ash

2018 ◽  
Vol 10 (6) ◽  
pp. 2004 ◽  
Author(s):  
Hector Campos Silva ◽  
Pedro Garces Terradillos ◽  
Emilio Zornoza ◽  
Jose Mendoza-Rangel ◽  
Pedro Castro-Borges ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Reinforced Concrete ◽  
Fly Ash ◽  
Blended Cement

Corrosion resistance of composite coating used for fastener protection

2019 ◽  
Vol 66 (5) ◽  
pp. 595-602
Author(s):  
Zhifeng Lin ◽  
Likun Xu ◽  
Xiangbo Li ◽  
Li Wang ◽  
Weimin Guo ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Carbon Steel ◽  
Composite Coating ◽  
Marine Environment ◽  
Electrochemical Impedance ◽  
Salt Spray ◽  
Diffusion Method ◽  
Economic Losses ◽  
Neutral Salt ◽  
Content Type

Purpose The purpose of this paper is to examine the performance of a fastener composite coating system, sherardized (SD) coating/zinc-aluminum (ZA) coating whether it has good performance in marine environment. Design/methodology/approach In this paper, SD coating was fabricated on fastener surface by solid-diffusion method. ZA coating was fabricated by thermal sintering method. Corrosion behaviours of the composite coating were investigated with potentiodynamic polarization curves, open circuit potential and electrochemical impedance spectroscopy methods. Findings Neutral salt spray (NSS) and deep sea exposure tests revealed that the composite coating had excellent corrosion resistance. Polarization curve tests showed that corrosion current density of the sample with composite coating was significantly decreased, indicating an effective corrosion protection of the composite coating. OCP measurement of the sample in NaCl solution demonstrated that the composite coating had the best cathodic protection effect. The good corrosion resistance of the composite coating was obtained by the synergy of SD and ZA coating. Practical implications SD/ZA coating can be used in marine environment to prolong the life of carbon steel fastener. Social implications SD/ZA composite coating can reduce the risk and accident caused by failed fastener, avoid huge economic losses. Originality/value A new kind of composite coating was explored to protect the carbon steel fastener in marine environment. And the composite coating has the long-term anti-corrosion performance both in simulated and marine environment test.

scholarly journals Erosion-Corrosion Protection Due to Cr3C2-NiCr Cermet Coating on Stainless Steel

Coatings ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1042
Author(s):  
Panneer Selvam Kevin ◽  
Abhishek Tiwari ◽  
Saravanan Seman ◽  
Syed Ali Beer Mohamed ◽  
Rengaswamy Jayaganthan
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Potentiodynamic Polarization ◽  
Electrochemical Impedance ◽  
Turbine Blades ◽  
Continuous Exposure ◽  
Hydro Power ◽  
Cermet Coating ◽  
Erosion Corrosion

Cr3C2–NiCr coatings have been used extensively to combat the erosion corrosion of hydro power turbine blades made of stainless steel. Cr3C2–NiCr coatings are also used in aqueous corrosive environments due to the high corrosion resistance rendered by the NiCr binder. In this investigation, both erosion and corrosion environments are introduced to cermet coating to study corrosion behavior using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The cermet coatings are useful for reducing the risk of deterioration of mechanical properties of hydro power turbines due to the continuous exposure to the erosive and corrosive action of the corrosive environment containing silt. It was observed that Cr3C2–NiCr coating offered a reasonable improvement in corrosion resistance when compared to bare substrate. The corrosion behavior of the coating was studied in a 150 mL solution of 0.1 M NaCl with 2 gms of quartz particles (0.2–0.8 mm) at various rotation speeds (3000, 4500, 6000 rpm) of the solution over a 1 h immersion using potentiodynamic polarization and EIS studies in a specifically designed experimental set-up for erosion corrosion. When compared to the bare stainless steel samples at 3000 rpm and 6000 rpm, the coating showed the highest improvement at 6.57 times and the least improvement at 3.79 times, respectively.

Research on Rust Bilge Cracking of Reinforced Concrete Pier in Marine Environment

2011 ◽  
Vol 368-373 ◽  
pp. 1073-1077
Author(s):  
Xiao Feng Luo ◽  
Guo Hui Xing
Keyword(s):  
Heat Transfer ◽  
Thermal Expansion ◽  
Reinforced Concrete ◽  
Marine Environment ◽  
Coefficient Of Thermal Expansion ◽  
Expansion Method ◽  
Ion Concentration ◽  
Transient Heat Transfer ◽  
Chloride Diffusion ◽  
Time Step

Based on coupled thermal-mechanical method, rust bilge cracking of reinforced concrete pier in marine environment has been studied in this paper. Because of the similarity of differential equations of chloride diffusion and transient heat transfer, chloride diffusion is completed by using the transient heat transfer method. The chloride ion concentration at the reinforcement surface is obtained and is taken as temperature load at each time step. After introducing the equivalent time-varying coefficient of thermal expansion, the corrosion-induced reinforcement expansion and concrete cracking are simulated by the thermal expansion method. Numerical results show that the method is reasonable and feasible.

Study of Corrosion Behavior of Friction Surfacing AA6351 Aluminium Alloy Coating on AISI 1020 Low Carbon Steel

2020 ◽  
Vol 1012 ◽  
pp. 401-406
Author(s):  
Carlos Trivellato de Carvalho Filho ◽  
Pedro Paiva Brito
Keyword(s):  
Surface Roughness ◽  
Corrosion Resistance ◽  
Carbon Steel ◽  
Corrosion Behavior ◽  
Electrochemical Impedance ◽  
Low Carbon Steel ◽  
Alloy Coating ◽  
Low Carbon ◽  
Friction Surfacing ◽  
Finishing Process

In the present work, the friction surfacing process was applied to manufacture aluminum alloy (AA6351) coatings on low carbon steel (AISI 1020) substrates. After friction surfacing the AA6351 deposited coatings were submitted to two finishing process in order to adjust surface roughness: milling and milling followed by sanding. The corrosion behavior of the two finishing process was compared with the as-deposited condition in order to determine the influence of surface roughness on the corrosion resistance of friction surfacing coatings. The corrosion behavior was examined by electrochemical impedance spectroscopy and potentiodynamic polarization in a 3.5wt.%NaCl solution containing naturally dissolved O2. The results obtained indicated that the elevated surface roughness observed in the as-deposited condition led to relatively lower corrosion resistance in comparison, with lower values for polarization resistance and more anodic corrosion potential.

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