Corrosion and Passivation of Tin Anode in Na2CO3 Solutions and the Effect of Halide Ions

1993 ◽  
Vol 58 (9) ◽  
pp. 2013-2020 ◽  
Author(s):  
Sayed S. Abd El-Rehim ◽  
Fouad Taha ◽  
Mohamed B. Saleh ◽  
Said A. Mohamed

The corrosion and passivation of tin anode in Na2CO3 (0.01 to 1.0 M) was investigated using potentiodynamic and cyclic voltammetry techniques and complemented by X-ray and scanning electron microscopy. The polarization curves exhibit two anodic peaks assigned to the electroformation of Sn(II) and Sn(IV) species, respectively, prior to permanent pssive region. The anodic dissolution reactions are controlled by diffusion. X-Ray diffraction showed that the permanent passive layer is duplex and consists of SnO and SnO2. A multiplicity of cathodic peaks is related to the electroconduction of the anodically formed compounds. Addition of Cl-, Br- or I- ions into the carbonate solutions enhances the anodic dissolution of tin to some extent depending upon the sodium carbonate concentration. In the passive region, addition of the halide ions causes pitting of the halide ions causes pitting corrosion at a critical pitting potential. The pitting potential decreases with increasing both the halide ion concentration and the scanning rate but increases with increasing the sodium carbonate concentration. SEM examination confirms the occurance of pitting corrosion.

2016 ◽  
Vol 230 (10) ◽  
Author(s):  
Hesham S. Abdel-Samad ◽  
Hamdy H. Hassan

AbstractThe corrosion behaviour of zinc metal was studied in acetate solutions. The potentiodynamic polarization curve in 0.1 M acetate solution displays an anodic peak (A1) owing to the anodic dissolution of zinc followed by a passive layer formation region. Breakdown of the passive film and the initiation of pitting corrosion were observed beyond the pitting potential (


2012 ◽  
Vol 538-541 ◽  
pp. 2342-2345
Author(s):  
Jun Li ◽  
Dong Ye ◽  
Yong Mei Chen ◽  
Jie Su ◽  
Kun Yu Zhao

Abstract. The pitting corrosion behavior of two kinds (W and Cu-free; W and Cu-bearing) of supermartensitic stainless steels (SMSS) were studied in CO2-saturated chloride solution with three chloric ion concentration: 21200, 50000, 100000ppm, and four different temperatures:19, 40, 60, 80°C by potentiodynamic polarization measurement. The results indicate that the pitting potential decreased with temperature increasing, and in a logarithmic relation with the chlorine concentration in both alloys. The pitting potential of supermartensitic stainless steel is increased by together adding tungsten and copper.


2019 ◽  
Vol 66 (3) ◽  
pp. 300-306
Author(s):  
Nobl Foad El Boraei ◽  
Sayed S. Abd El Rehim ◽  
Hamdy H. Hassan

Purpose The purpose of this paper is to study the electrochemical behavior of Sn electrode in Na2B2O7 solutions in the absence and presence of NaNO3 as a pitting corrosion agent. Design/methodology/approach The electrochemical behavior of Sn electrode was studied by using cyclic voltammetry and potentiodynamic polarization measurements and complemented with scanning electron microscopy examinations. Findings This paper shows that in the absence of NO3 − ions, the anodic polarization of Sn electrode exhibits active/passive transition. Addition of various concentrations of NO3 − anions to the borate solution enhances active anodic dissolution and tends to break down the passive oxide film at a certain pitting potential. The pitting potential, and hence the pitting corrosion resistance, decreases with increasing NO3-ion concentration and temperature but increases with scan rate and repetitive cycling. Addition of CrO42−, WO42− or MoO42− oxyanions to the borate nitrate solution inhibits the pitting corrosion of Sn. Originality/value This is the first study that shows the effect of NO3 − ion as a pitting corrosion agent.


2018 ◽  
Vol 940 ◽  
pp. 59-64 ◽  
Author(s):  
Xin Zhang ◽  
De Ning Zou ◽  
Yu Qing Zhou ◽  
Xuan Na ◽  
Wei Zhang ◽  
...  

The corrosion behavior of maraging hardened stainless steel (MHSS) in different Cl-medium was investigated by thermodynamics simulation and electrochemical experiments. The simulation results show that the thermodynamic stability zone decreases with the increase of the concentration of Cl-. Some of chromium transformed into Cr(OH)2+and adsorbed on the surface of stainless steel, and others generated Cr2O3protecting the matrix. Mo reacted with O2to form MoO42-adsorbed on the surface of the material, which inhibited the destruction of Cl-. The electrochemical experiments indicate that the concentration of Cl-is in the range of 2%-7%. The pitting potential and self-corrosion potential of MHSS decreased linearly with the increase of ion concentration, and the pitting corrosion resistance of MHSS decreased. When the self-corrosion current increases from 1.9888 μA to 2.6524 μA, the corrosion tendency of the material enhances.


Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1233 ◽  
Author(s):  
Nader El-Bagoury ◽  
Sameh I. Ahmed ◽  
Ola Ahmed Abu Ali ◽  
Shimaa El-Hadad ◽  
Ahmed M. Fallatah ◽  
...  

The effect of microstructure and chemistry on the kinetics of passive layer growth and passivity breakdown of some Ti-based alloys, namely Ti-6Al-4V, Ti-6Al-7Nb and TC21 alloys, was studied. The rate of pitting corrosion was evaluated using cyclic polarization measurements. Chronoamperometry was applied to assess the passive layer growth kinetics and breakdown. Microstructure influence on the uniform corrosion rate of these alloys was also investigated employing dynamic electrochemical impedance spectroscopy (DEIS). Corrosion studies were performed in 0.9% NaCl solution at 37 °C, and the obtained results were compared with ultrapure Ti (99.99%). The different phases of the microstructure were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Chemical composition and chemistry of the corroded surfaces were studied using X-ray photoelectron spectroscopy (XPS) analysis. For all studied alloys, the microstructure consisted of α matrix, which was strengthened by β phase. The highest and the lowest values of the β phase’s volume fraction were recorded for TC21 and Ti-Al-Nb alloys, respectively. The susceptibility of the investigated alloys toward pitting corrosion was enhanced following the sequence: Ti-6Al-7Nb < Ti-6Al-4V << TC21. Ti-6Al-7Nb alloy recorded the lowest pitting corrosion resistance (Rpit) among studied alloys, approaching that of pure Ti. The obvious changes in the microstructure of these alloys, together with XPS findings, were adopted to interpret the pronounced variation in the corrosion behavior of these materials.


Author(s):  
Nader El-Bagoury ◽  
Sameh Ibrahim ◽  
Ola Ahmed Abu Ali ◽  
Shimaa El-Hadad ◽  
Ahmed M. Fallatah ◽  
...  

The effect of microstructure and chemistry of passive films on the kinetics of passive layer growth and passivity breakdown of some Ti-based alloys, namely Ti-6Al-4V, Ti-6Al-7Nb and TC21 alloys was studied. The rate of pitting corrosion was evaluated using cyclic polarization measurements. Chronoamperometry was applied to assess the passive layer growth kinetics and breakdown. Microstructure influence on the uniform corrosion rate of these alloys was also investigated employing Tafel extrapolation and dynamic electrochemical impedance spectroscopy. Corrosion studies were performed in 0.9% NaCl solution at 37 oC, and the obtained results were compared with ultrapure Ti (99.99%). The different phases of the microstructure were characterized by X-ray diffraction and scanning electron microscopy. Chemical composition and chemistry of the corroded surfaces were studied using X-ray photoelectron analysis. For all studied alloys, the microstructure consisted of &alpha; matrix, which was strengthened by &beta; phase. The highest and the lowest values of the &beta; phase&rsquo;s volume fraction were recorded for TC21 and Ti-Al-Nb alloys, respectively. The uniform corrosion rate and pitting corrosion resistance (Rpit) of the studied alloys were enhanced following the sequence: Ti-6Al-7Nb &lt; Ti-6Al-4V &lt;&lt; TC21. The corrosion resistance of Ti-Al-Nb alloy approached that of pure Ti. The obvious changes in the microstructure of these alloys, together with XPS findings, were adopted to interpret the pronounced variation in their corrosion rates.


2021 ◽  
Vol 16 (2) ◽  
pp. 234-243
Author(s):  
Fahd Arboui ◽  
Sid Ahmed Amzert ◽  
Mohamed Nadir Boucherit ◽  
Salah Hanini ◽  
Khaoula Ghezali

The efficiency of permanganates to inhibit the scale deposit captured the attention for more investigation on their role as corrosion inhibitor. In this article, the effect of permanganate as corrosion inhibitor on 316L stainless steel in NaCl solution is investigated. The potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) have been performed by varying the electrode stirring speed, the concentration of permanganate ions, pH and the temperature. The results show that the permanganate ions increase the cathodic and anodic currents under effect of stirring speed, due to oxygen reduction reaction and the reduction of permanganate ions. Electrochemical results indicate that the deposit of manganese oxide (MnO2) inhibits the pitting corrosion. The inhibition efficiency is up to 98 % for 10−4 mol.dm−3 of permanganate. The temperature reduces the effectiveness of permanganates against pitting corrosion, the pitting potential shifts cathodically from +0.395 V vs. Saturated Calomel Electrode (SCE) at 298 K to +0.275 V vs. SCE at 343 K. Surface morphology of the deposit oxide films and electrode are studied by emission scanning electron microscopy, X-ray diffraction, Fourier transform infrared and Differential Scanning Calorimetry. The analysis of the deposit layer by X-ray diffraction revealed the presence of δ-MnO2 form, with a crystallite size of 3.17 nm.  Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0). 


Author(s):  
Anwar Ameen Hezam Saeed ◽  
Noorfidza Yub Harun ◽  
Suriati Sufian ◽  
Muhammad Roil Bilad ◽  
Zaki Yamani Zakaria ◽  
...  

Development of strategies for removing heavy metals from aquatic environments is in high demand. Cadmium is one of the most dangerous metals in the environment, even under extremely low quantities. In this study, kenaf and magnetic biochar composite were prepared for the adsorption of Cd2+. The synthesized biochar was characterized using (a vibrating-sample magnetometer VSM), Scanning electron microscopy (SEM), X-ray powder diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). The adsorption batch study was carried out to investigate the influence of pH, kinetics, isotherm, and thermodynamics on Cd2+ adsorption. The characterization results demonstrated that the biochar contained iron particles that help in improving the textural properties (i.e., surface area and pore volume), increasing the number of oxygen-containing groups, and forming inner-sphere complexes with oxygen-containing groups. The adsorption study results show that optimum adsorption was achieved under pH 5–6. An increase in initial ion concentration and solution temperature resulted in increased adsorption capacity. Surface modification of biochar using iron oxide for imposing magnetic property allowed for easy separation by external magnet and regeneration. The magnetic biochar composite also showed a higher affinity to Cd2+ than the pristine biochar. The adsorption data fit well with the pseudo-second-order and the Langmuir isotherm, with the maximum adsorption capacity of 47.90 mg/g.


Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1068
Author(s):  
Xinyue Zhang ◽  
Yani Guo ◽  
Wenjun Li ◽  
Jinyuan Zhang ◽  
Hailiang Wu ◽  
...  

The treatment of wastewater containing heavy metals and the utilization of wool waste are very important for the sustainable development of textile mills. In this study, the wool keratin modified magnetite (Fe3O4) powders were fabricated by using wool waste via a co-precipitation technique for removal of Cu2+ ions from aqueous solutions. The morphology, chemical compositions, crystal structure, microstructure, magnetism properties, organic content, and specific surface area of as-fabricated powders were systematically characterized by various techniques including field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), vibrating sample magnetometer (VSM), thermogravimetric (TG) analysis, and Brunauer–Emmett–Teller (BET) surface area analyzer. The effects of experimental parameters such as the volume of wool keratin hydrolysate, the dosage of powder, the initial Cu2+ ion concentration, and the pH value of solution on the adsorption capacity of Cu2+ ions by the powders were examined. The experimental results indicated that the Cu2+ ion adsorption performance of the wool keratin modified Fe3O4 powders exhibited much better than that of the chitosan modified ones with a maximum Cu2+ adsorption capacity of 27.4 mg/g under favorable conditions (0.05 g powders; 50 mL of 40 mg/L CuSO4; pH 5; temperature 293 K). The high adsorption capacity towards Cu2+ ions on the wool keratin modified Fe3O4 powders was primarily because of the strong surface complexation of –COOH and –NH2 functional groups of wool keratins with Cu2+ ions. The Cu2+ ion adsorption process on the wool keratin modified Fe3O4 powders followed the Temkin adsorption isotherm model and the intraparticle diffusion and pseudo-second-order adsorption kinetic models. After Cu2+ ion removal, the wool keratin modified Fe3O4 powders were easily separated using a magnet from aqueous solution and efficiently regenerated using 0.5 M ethylene diamine tetraacetic acid (EDTA)-H2SO4 eluting. The wool keratin modified Fe3O4 powders possessed good regenerative performance after five cycles. This study provided a feasible way to utilize waste wool textiles for preparing magnetic biomass-based adsorbents for the removal of heavy metal ions from aqueous solutions.


Minerals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 533 ◽  
Author(s):  
Xin Zhang ◽  
Guanghui Li ◽  
Jinxiang You ◽  
Jian Wang ◽  
Jun Luo ◽  
...  

Ludwigite ore is a typical low-grade boron ore accounting for 58.5% boron resource of China, which is mainly composed of magnetite, lizardite and szaibelyite. During soda-ash roasting of ludwigite ore, the presence of lizardite hinders the selective activation of boron. In this work, lizardite and szaibelyite were prepared and their soda-ash roasting behaviors were investigated using thermogravimetric-differential scanning calorimetry (TG-DSC), X-ray diffraction (XRD), and scanning electron microscope and energy dispersive spectrometer (SEM-EDS) analyses, in order to shed light on the soda-ash activation of boron within ludwigite ore. Thermodynamics of Na2CO3-MgSiO3-Mg2SiO4-Mg2B2O5 via FactSage show that the formation of Na2MgSiO4 was preferential for the reaction between Na2CO3 and MgSiO3/Mg2SiO4. While, regarding the reaction between Na2CO3 and Mg2B2O5, the formation of NaBO2 was foremost. Raising temperature was beneficial for the soda-ash roasting of lizardite and szaibelyite. At a temperature lower than the melting of sodium carbonate (851 °C), the soda-ash roasting of szaibelyite was faster than that of lizardite. Moreover, the melting of sodium carbonate accelerated the reaction between lizardite with sodium carbonate.


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