scholarly journals ELECTROCHEMICAL CORROSION PERFORMANCE OF COMMERCIALLY USED ALUMINIUM ENGINE BLOCK AND PISTON IN 0.1M NaCl

2015 ◽  
Vol 45 (1) ◽  
pp. 48-52 ◽  
Author(s):  
M S Kaiser ◽  
M R Qadir ◽  
Swagata Dutta
Keyword(s):  
Corrosion Potential ◽  
Electrochemical Impedance ◽  
Corrosion Behaviour ◽  
Optical Microscope ◽  
Engine Block ◽  
Lower Percentage ◽  
Corrosion Performance ◽  
Transfer Resistance ◽  
Piston Alloy ◽  
Aluminium Piston

The corrosion behaviour of commercially used aluminium engine block and piston were investigated in 0.1M NaCl solution at room temperatures. The study was done by electrochemical method, using Tafel polarization and electrochemical impedance spectroscopy (EIS) techniques. The surface was characterized by optical microscope and scanning electron microscope (SEM). The results indicated differences in the charge transfer resistance of engine block and piston alloys. The current density (Icorr) of engine block material showed higher value than that of piston material. The corrosion potential (Ecorr) and pitting corrosion potential (Epit) of piston material were shifted to the more noble direction. In aluminium piston alloy there seems to be uniform surface pits formations which are in fewer amounts as compared to those in engine block alloy. The corrosion performance of aluminium piston alloy was found to be higher than that of aluminium engine block due to the presence of Ni and lower percentage of Fe in aluminium piston alloy.   

scholarly journals Protection of Carbon Steel Rebars by Epoxy Coating with Smart Environmentally Friendly Microcapsules

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 113
Author(s):  
Jacob Ress ◽  
Ulises Martin ◽  
Juan Bosch ◽  
David M. Bastidas
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Corrosion Protection ◽  
Corrosion Potential ◽  
Electrochemical Impedance ◽  
Pore Solution ◽  
Control Sample ◽  
Chloride Ions ◽  
Epoxy Coating ◽  
Transfer Resistance

The protection of mild steel by modified epoxy coating containing colophony microencapsulated corrosion inhibitors was investigated in this study. The corrosion behavior of these epoxy coatings containing colophony microcapsules was studied by electrochemical analysis using cyclic potentiodynamic polarization and electrochemical impedance spectroscopy. The microcapsule coating showed decreased corrosion current densities of 2.75 × 10−8 and 3.21 × 10−8 A/cm2 along with corrosion potential values of 0.349 and 0.392 VSCE for simulated concrete pore solution and deionized water with 3.5 wt.% NaCl, respectively, indicating improved corrosion protection in both alkaline and neutral pH. Electrochemical impedance spectroscopy analysis also showed charge transfer resistance values over one order of magnitude higher than the control sample, corroborating the electrochemical corrosion potential and current density testing results. Overall, the use of colophony microcapsules showed improved corrosion protection in simulated concrete pore solution and DI water solutions containing chloride ions.

scholarly journals INFLUENCE OF A PREFABRICATED-CROWN ROLLING PROCESS ON THE CORROSION BEHAVIOUR OF AZ31 MAGNESIUM ALLOY

2021 ◽  
Vol 55 (4) ◽  
Author(s):  
Zhiquan Huang ◽  
Jinchao Zou ◽  
Junpeng Wang ◽  
Yanjie Pei ◽  
Renyao Huang ◽  
...  
Keyword(s):  
Magnesium Alloy ◽  
Corrosion Behavior ◽  
Electrochemical Impedance ◽  
Corrosion Behaviour ◽  
Plate Thickness ◽  
Az31 Alloy ◽  
Rolling Process ◽  
Charge Transfer Resistance ◽  
Az31 Magnesium Alloy ◽  
Transfer Resistance

The present study aims to investigate the effect of a prefabricated-crown rolling process on the corrosion characteristic of the AZ31 magnesium alloy. Specimens made of the AZ31 alloy were rolled under various crown conditions, and their microstructure evolution and corrosion behavior were analyzed. The corrosion behavior was studied using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results showed that the corrosion-current density of the AZ31 alloy with a side pressure of 37.5 % of the plate thickness of the precast convexity decreased from 3.79 × 10–6 A/cm2 to 1.80 × 10–6 A/cm2, and the difference between the edge and the middle of the AZ31 alloy was shortened from 2.05 × 10–6 A/cm2 to 1.14 × 10–6 A/cm2. The charge-transfer resistance also increased from 507.1 Ω·cm2 to 581.2 Ω·cm2. The improvement in the corrosion resistance is a result of the more stable corrosion products and microstructure refinement formed after the prefabricated-crown rolling process.

Corrosion performance of mild steel and epoxy coated rebar in concrete under simulated harsh environment

2019 ◽  
Vol 37 (5) ◽  
pp. 657-678
Author(s):  
Muazzam Ghous Sohail ◽  
Mohammad Salih ◽  
Nasser Al Nuaimi ◽  
Ramazan Kahraman
Keyword(s):  
Mild Steel ◽  
Polarization Resistance ◽  
Electrochemical Impedance ◽  
Corrosion Current ◽  
Charge Transfer Resistance ◽  
Harsh Environment ◽  
Corrosion Performance ◽  
Transfer Resistance ◽  
Content Type ◽  
Rc Structures

Purpose The purpose of this paper is to present the results of a two-year long study carried out in order to evaluate the corrosion performance of mild steel bare bars (BB) and epoxy-coated rebar (ECR) in concrete under a simulated harsh environment of chlorides. Design/methodology/approach The blocks are subjected to Southern Exposure testing. The electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR) and Tafel plot are performed to measure the polarization resistance and corrosion current densities of these rebars. Knife-peel test was performed to assess the adhesion between epoxy and underlying steel after two years of exposure. Findings Mild steel BB showed a high corrosion current density of 1.24 µA/ cm2 in Tafel plots and a very low polarization resistance of 4.5 kΩ cm2 in LPR technique, whereas very high charge transfer resistance of 1672 and 1675 kΩ cm2 is observed on ECR and ECR with controlled damage (ECRCD), through EIS technique, respectively. EIS is observed to be a suitable tool to detect the defects in epoxy coatings. After two years of immersion in 3.89 percent NaCl− solution, the mild steel BB were severely corroded and a considerable weight loss was observed, whereas under heavy chloride attack, ECR showed no deterioration of epoxy coating and neither any corrosion of underlying steel. Results of this study show that the durability of reinforced concrete (RC) structures with respect to corrosion could be enhanced by using ECR, especially in harsh climatic conditions. Originality/value The corrosion performance of mild steel and ECR in concrete under a simulating splash zone environment is evaluated. EIS was used to evaluate the health of epoxy and corrosion state of underneath steel rebars. EIS was able to detect the defects in epoxy. The durability of RC structures could be enhanced in harsh climate regions by using ECR.

Effect of Experimental Parameters on Passivation Phenomena of Ti6Al4V Alloy in Acid Solution

2016 ◽  
Vol 710 ◽  
pp. 204-209
Author(s):  
Elamine Nouicer ◽  
Fatima Zohra Benlahreche ◽  
Abdelmadjid Nouicer
Keyword(s):  
Oxide Film ◽  
Acid Solution ◽  
Corrosion Potential ◽  
Large Range ◽  
Electrochemical Impedance ◽  
Ti6al4v Alloy ◽  
Paper Study ◽  
Transfer Resistance ◽  
Experimental Parameters ◽  
Increasing Trend

This paper study the effect of scan rates and imposed potential on the growth of the oxide film on the Ti6Al4V alloy surface in acid solution .Polarization curves, plotted at different scan rates show a large range of passivation, with no occurrence of transpassivation . It was found that the scan rate have not a significant effect on the passivation phenomenon. However, it influences the corrosion potential and the current density. Electrochemical impedance spectroscopy results show that the system behaviour is purely capacitive. The increasing trend in transfer resistance, film thickness and the exponent n with the imposed potential is due to the growth of a passive and compact oxide film.

scholarly journals Electrochemical properties and thermal stability of epoxy coatings electrodeposited on aluminium and modified aluminium surfaces

2001 ◽  
Vol 66 (11-12) ◽  
pp. 871-880 ◽  
Author(s):  
Vesna Miskovic-Stankovic ◽  
Zorica Lazarevic ◽  
Zorica Kacarevic-Popovic
Keyword(s):  
Thermal Stability ◽  
Electrochemical Impedance ◽  
Corrosion Behaviour ◽  
Charge Transfer Resistance ◽  
Epoxy Coatings ◽  
Transfer Resistance ◽  
Protective Properties ◽  
Chemically Modified ◽  
Thermal Stability Of

The corrosion behaviour of epoxy coatings electrodeposited on aluminium, as well as on electrochemically and chemically modified aluminium were investigated during exposure to 3 % NaCl. Electrochemical impedance spectroscopy (EIS) and thermogravimetric analysis (TGA) were used for the determination of the protective properties of epoxy coatings on aluminium, anodized aluminium, phosphatized and chromatized-phosphatized aluminium. The protective properties of epoxy coatings on anodized and chromatized-phosphatized aluminium are significantly improved with respect to the same epoxy coatings on aluminium and phosphatized aluminium: higher values of the pore resitance and charge-transfer resistance, lower values of the coating capacitance, double-layer capacitance and relative permittivity (from EIS) smaller amount of absorbed water inside the coating (From TGA). On the other hand, the lower values of the ipdt temperature indicate a lower thermal stability of the epoxy coatings on anodized and chromatized-phosphatized aluminium.

scholarly journals Recycling of Expired Ceftamil Drug as Additive in the Copper and Nickel Electrodeposition from Acid Baths

2021 ◽  
Vol 18 (18) ◽  
pp. 9476
Author(s):  
Delia-Andrada Duca ◽  
Mircea Laurențiu Dan ◽  
Nicolae Vaszilcsin
Keyword(s):  
Organic Molecules ◽  
Electrochemical Impedance ◽  
Electrolyte Solutions ◽  
Optical Microscope ◽  
Charge Transfer Resistance ◽  
Favorable Effect ◽  
Transfer Resistance ◽  
Nickel Electrodeposition ◽  
Nickel Electroplating ◽  
Different Temperatures

Due to the large quantity of expired and unused drugs worldwide, pharmaceutical disposal has become a serious problem that requires increased attention. In the present paper, the study on recycling ceftazidime (CZ) as an additive in copper and nickel electrodeposition from acid baths is highlighted. CZ is the active substance from expired commercial drug Ceftamil®. Its electrochemical behavior was studied by cyclic voltammetry. As well, kinetic parameters for copper and nickel electrodeposition were determined using Tafel plots method at different temperatures and CZ concentrations in these acid baths. The activation energy was calculated from Arrhenius plots. Electrochemical impedance spectroscopy was used to investigate the charge transfer resistance and coverage degree in the electrolyte solutions at several potential values. Gibbs free energy values, calculated from Langmuir adsorption isotherms, revealed the chemical nature of CZ–electrode surface interactions. The favorable effect of the organic molecules added in copper and nickel electroplating baths was emphasized by optical microscope images. The morphology of the obtained deposits without and with 10−4 mol L−1 CZ was compared. The experimental results revealed that expired Ceftamil® is suitable as additive in copper and nickel electroplating processes from acid baths.

scholarly journals Microstructural Evolutions and its Impact on the Corrosion Behaviour of Explosively Welded Al/Cu Bimetal

Metals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 634
Author(s):  
Mohammad Reza Jandaghi ◽  
Abdollah Saboori ◽  
Gholamreza Khalaj ◽  
Mohammadreza Khanzadeh Ghareh Shiran
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Potential ◽  
Electrochemical Impedance ◽  
Corrosion Behaviour ◽  
Welding Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Aluminium Copper ◽  
Melting Pool ◽  
Intermetallic Layers

In this study, the microstructural evolutions and corrosion resistance of aluminium/copper joint fabricated through explosive welding process have been thoroughly investigated, while stand-off distance was variable. Microstructural analyses demonstrate that, regardless of grain refinement in the welding boundary, increasing the stand-off space is followed by a higher thickness of the localized melting pool. X-Ray diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDS) analyses recognized the binary intermetallic layers as a combination of Al2Cu and AlCu. Polarization and electrochemical impedance spectroscopy (EIS) corrosion tests revealed that a higher stand-off distance resulted in the increment of corrosion potential, current rate, and concentration gradient at the interface owing to the remarkable kinetic energy of the collision, which impaired corrosion resistance.

Corrosion Resistance of Zn-Al-Mg Alloys with Hypoeutectic Microstructure

2019 ◽  
Vol 298 ◽  
pp. 52-58
Author(s):  
Guang Rui Jiang ◽  
Jian Zhou ◽  
Ting Shang ◽  
Guang Hui Liu
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Potential ◽  
Electrochemical Impedance ◽  
Ternary Eutectic ◽  
Corrosion Current ◽  
Charge Transfer Resistance ◽  
Mg Alloys ◽  
Transfer Resistance ◽  
Warburg Impedance ◽  
Al Mg Alloys

Zn-Al-Mg alloys with hypoeutectic microstructure were melted through a high frequency induction furnace. The content of aluminum and magnesium in the alloys were between 1% to 2%. Scanning electron microscopy (SEM) was utilized to analyze microstructure and phase, respectively. Effect of alloying element contents on corrosion resistance was studied. Results show that the Zn-Al-Mg alloys are almost covered by primarily solidified Zn rich block phase and fine lamellar binary and ternary eutectic microstructure exist between the Zn rich phase. The corrosion resistance was characterized through electrochemical test which indicates that increasing Al and Mg content in the Zn-Al-Mg alloys decline corrosion current density. For alloys with 1% Al, more magnesium means lower corrosion potential. For alloys with 2% Al, however, more magnesium suggests higher corrosion potential. In Nyquist curves of electrochemical impedance spectroscopy (EIS) test, Warburg impedance portion could be found for all alloys. With increasing alloying elements content in the Zn-Al-Mg alloys, charge transfer resistance in higher frequency remarkably increase, which implies higher corrosion resistance.

scholarly journals Electrochemical Investigation of Corrosion Behavior Heat Treated Al-6Si-0.5Mg-xCu (x = 0, 0.5, 1, 2, and 4 wt%) Alloys

2014 ◽  
Vol 2014 ◽  
pp. 1-6
Author(s):  
A. Hossain ◽  
F. Gulshan ◽  
A. S. W. Kurny
Keyword(s):  
Charge Transfer ◽  
Potentiodynamic Polarization ◽  
Corrosion Potential ◽  
Electrochemical Impedance ◽  
Charge Transfer Resistance ◽  
Nacl Solution ◽  
Transfer Resistance ◽  
Cu Content ◽  
Cu Alloy ◽  
Heat Treated

The corrosion behaviour of heat treated Al-6Si-0.5Mg-xCu (x=0.5, 1, 2, and 4 wt%) alloys in 0.1 M NaCl solution was investigated using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The potentiodynamic polarization curves reveal that 2 wt% Cu (Alloy-4) and 4 wt% Cu (Alloy-5) content alloys are more prone to corrosion than the other alloys investigated. But the EIS test results showed that charge transfer resistance (Rct) increases with increasing Cu content into Al-6Si-0.5Mg. Maximum charge transfer resistance (Rct) is reported with the addition of 2 wt% Cu and minimumRctvalue is for 4 wt% Cu content Al-6Si-0.5Mg alloy. Due to additions of Cu into Al-6Si-0.5Mg alloy, the magnitudes of open circuit potential (OCP), corrosion potential (Ecorr), and pitting corrosion potential (Epit) in NaCl solution were shifted to the more noble direction.

scholarly journals The Effects of Heat Treatment on the Electrochemical Properties and Corrosion of Aluminium Alloy AA8011 in an Aqueous Acid Media

2013 ◽  
Vol 24 ◽  
pp. 17-31 ◽  
Author(s):  
B. Okeoma Kelechukwu ◽  
O. Owate Israel ◽  
E. Oguzie Emeka ◽  
M. Mejeha Ihebrodike ◽  
Nnanna Lebe ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Aluminium Alloy ◽  
Lattice Distortion ◽  
Electrochemical Impedance ◽  
Corrosion Behaviour ◽  
Defect Size ◽  
Active Dissolution ◽  
Acid Media ◽  
Transfer Resistance ◽  
Positive Effects

Effects of heat treatment and quenching regimen on the electrochemical corrosion behaviour of aluminium alloy AA8011 in 0.1M H2SO4 was studied by open circuit potential, potentiodynamic polarization and electrochemical impedance spectroscopy measurements. Three different specimens (untreated/control, air -quenched oven- quenched) were investigated. Polarization results show that all the specimens underwent active dissolution, with no distinctive transition to passivation, heat treatment was observed to shift the corrosion potential towards low anodic values and decreased the rates of anodic partial reactions of the corrosion process. Electrochemical investigations reveal that heat treatment techniques have positive impacts on the alloy as indicated in increase in charge transfer resistance, polarization resistance and decrease in double layer capacitance. These positive effects are attributed to decrease in mean defect size and increase in lattice distortion of the crystallites in the heat treated specimens of the alloy. Studies of X-ray diffraction (XRD) spectra, scanning electron microscopy (SEM) morphologies of control, air and oven quenched samples of AA8011 aluminium alloy indicate decrease in mean defect size of 18.97% and 40.44%; increase in the lattice distortion of 11.07% and 20.04% for air and oven quenched specimens respectively.

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