Pitting Corrosion of Zn Peculiarly Caused by Acetate Anions

2016 ◽  
Vol 230 (10) ◽  
Author(s):  
Hesham S. Abdel-Samad ◽  
Hamdy H. Hassan
Keyword(s):  
Passive Film ◽  
Pitting Corrosion ◽  
Potentiodynamic Polarization ◽  
Corrosion Behaviour ◽  
Passive Layer ◽  
Acetate Solution ◽  
Layer Formation ◽  
Potentiodynamic Polarization Curve ◽  
Pitting Potential ◽  
Formation Region

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 (

Treatment of As(V) and As(III) by electrocoagulation using Al and Fe electrode

2009 ◽  
Vol 60 (5) ◽  
pp. 1341-1346 ◽  
Author(s):  
W. H. Kuan ◽  
C. Y. Hu ◽  
M. C. Chiang
Keyword(s):  
Passive Film ◽  
Potentiodynamic Polarization ◽  
Electrode Materials ◽  
Initial Period ◽  
Electrode System ◽  
Initial Solution ◽  
Alkaline Condition ◽  
Bipolar Electrode ◽  
Pitting Potential ◽  
Fe Hydroxide

A batch electrocoagulation (EC) process with bipolar electrode and potentiodynamic polarization tests with monopolar systems were investigated as methods to explore the effects of electrode materials and initial solution pH on the As(V) and As(III) removal. The results displayed that the system with Al electrode has higher reaction rate during the initial period from 0 to 25 minutes than that of Fe electrode for alkaline condition. The pH increased with the EC time because the As(V) and As(III) removal by either co-precipitation or adsorption resulted in that the OH positions in Al-hydroxide or Fe-hydroxide were substituted by As(V) and As(III). The pH in Fe electrode system elevate higher than that in Al electrode because the As(V) removal substitutes more OH position in Fe-hydroxide than that in Al-hydroxide. EC system with Fe electrode can successfully remove the As(III) but system with Al electrode cannot because As(III) can strongly bind to the surface of Fe-hydroxide with forming inner-sphere species but weakly adsorb to the Al-hydroxide surface with forming outer-sphere species. The acidic solution can destroy the deposited hydroxide passive film then allow the metallic ions liberate into the solution, therefore, the acidic initial solution can enhance the As(V) and As(III) removal. The over potential calculation and potentiodynamic polarization tests reveal that the Fe electrode systems possess higher over potential and pitting potential than that of Al electrode system due to the fast hydrolysis of and the occurrence of Fe-hydroxide passive film.

Corrosion Behaviour of Ti6Al4V and TiMo10Zr4 Alloys in the Ringer’s Solution: Effect of pH and Plastic Strain

2015 ◽  
Vol 227 ◽  
pp. 435-438 ◽  
Author(s):  
Joanna Loch ◽  
Alicja Łukaszczyk ◽  
Vincent Vignal ◽  
Halina Krawiec
Keyword(s):  
Corrosion Resistance ◽  
Plastic Strain ◽  
Titanium Alloys ◽  
Passive Film ◽  
Current Density ◽  
Potentiodynamic Polarization ◽  
Corrosion Behaviour ◽  
Ringer’S Solution ◽  
Ph Values

The corrosion behaviour of titanium alloys is not well understood – especially the role of the microstructure and plastic strain. In this paper, the influence of the microstructure and plastic strain on the corrosion resistance of TiMo10Zr4 and Ti6Al4V alloys was studied in the Ringer’s solution at 37 °C. Measurements were performed for different pH values and in aerated and de-aerated solutions using potentiodynamic polarization techniques. Results obtained on the two alloys were compared. It was shown that in the absence of plastic strain TiMo10Zr4 shows better corrosion resistance than Ti6Al4V (especially for pH = 8). By contrast, the current density in the passive range measured after 8% plastic strain was greater on TiMo10Zr4 than on Ti6Al4V, indicating that the passive film on TiMo10Zr4 is less protective than that formed on Ti6Al4V.

scholarly journals Role of NaCl, CO2, and H2S on Electrochemical Behavior of 304 Austenitic Stainless Steel in Simulated Oil Industry Environment

Metals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1347
Author(s):  
Hany S. Abdo ◽  
Asiful H. Seikh
Keyword(s):  
Raman Spectroscopy ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Passive Film ◽  
Potentiodynamic Polarization ◽  
Electrochemical Behavior ◽  
Passive Layer ◽  
Metallic Surface ◽  
Sem Images ◽  
304 Austenitic Stainless Steel

The electrochemical behavior of 304 austenitic stainless steel (304ASS) was studied by different methods such as potentiodynamic polarization, EIS, SEM, and Raman spectroscopy. Potentiodynamic polarization data suggest that 304 ASS could be more susceptible to corrosion due to the presence of H2S. The coexistence of H2S and Cl−-type ionic species in 304 ASS lead to a decrease in the corrosion resistance as compared to the H2S-free condition. It is seen that CO2 helps form a passive layer on the metallic surface, which eventually decreases its corrosion rate. Raman spectroscopy analysis shows that the passive layer developed under different condition consists of FeCO3, FeS2, Fe2O3, Fe(OH)2, etc. SEM images further confirm that elemental S− and Cl− can infiltrate the passive film and cause the passive film to deteriorate.

Corrosion Behavior of Sealed Films on Anodized Al Alloy

2011 ◽  
Vol 233-235 ◽  
pp. 1498-1501
Author(s):  
Qi Zhou ◽  
Chun Lin He ◽  
Qing Kui Cai
Keyword(s):  
Potentiodynamic Polarization ◽  
Open Circuit Potential ◽  
Corrosion Behaviour ◽  
Sol Gel ◽  
Open Circuit ◽  
Green Technology ◽  
Al Alloy ◽  
Corrosion Mechanism ◽  
Pitting Potential ◽  
Corrosive Solution

Alumina sol sealing is one of new green technology for anodized Al alloy. The corrosion mechanism of films sealed by sol and corrosion behaviour of films sealed by sol, Na2Cr2O7, boiling water were analyzed by their curves of open circuit voltage-time (E-T) and potentiodynamic polarization curve. It is found that corrosion tendency of sol sealing film is less than other sealed films by E-T inspection. Fluctuation of open-circuit potential is furious in the immersing prophase and slows down in the anaphase for anodized sealed films. At this time corrosive reactions gradually reach steady state. Open-circuit potential greatly waves for the rough sealed films. Potentiodynamic polarization curves of sealed films show that passive area is the longest for films sealed by sol which has the minimum corrosive current , the passivate current, anodic current and cathode current, but the maximum pitting potential and open-circuit potential. Corrosion parameters are the second for the film sealed by dichromate. Anodic reactions are strongly inhibited by sol sealing films in Cl- corrosive solution. Sol sealing films weaken cathode O2 depolarize reaction. Cl- ions erode anodized Al material on which covered with sol film and produce corrosion. The corrosion of sol-gel film goes through two periods: pitting induced phase and pitting corrosion period.

Electrochemical Properties of Passive Film Formed on Supermartensitic Stainless Steel in a Chloride Medium

CORROSION ◽  
10.5006/3230 ◽  
2020 ◽  
Vol 76 (9) ◽  
pp. 884-890
Author(s):  
Renata B. Soares ◽  
Wagner R.C. Campos ◽  
Pedro L. Gastelois ◽  
Waldemar A.A. Macedo ◽  
Luís F.P. Dick ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Stainless Steel ◽  
Passive Film ◽  
Electrochemical Behavior ◽  
Photoelectron Spectroscopy ◽  
Oil And Gas ◽  
Electrochemical Impedance ◽  
Passive Layer ◽  
Open Circuit ◽  
Pitting Potential

The electrochemical behavior and the electronic properties of passive films formed on a super martensitic stainless steel (SMSS) used in oil and gas industries were investigated in aqueous 0.6 M and 2.1 M NaCl solutions with additions of sodium acetate and acetic acid (pH 4.5). Open-circuit potential transients, electrochemical impedance spectroscopy, cyclic voltammetry, and x-ray photoelectron spectroscopy were measured to characterize the passive film formed on SMSS. The electrochemical behavior of the steel in an aqueous solution of 0.6 M NaCl presented the highest pitting potential and the highest polarization resistance in relation to the NaCl/NaAc solution. The passive film of SMSS in an aqueous solution of NaCl presented a thickness of 18.40 nm, three times the thickness of the oxide film in NaCl/NaAc, and consisted of FeO, Cr2O3, MoO2, and spinels such as FeCr2O4 species that are a p-type semiconductor, but may also contain a small fraction of the Fe2O3 and MoO3 oxides. Additionally, it was shown that the passive layer after immersion in a saline solution also contains hydroxides such as FeOOH and Cr(OH)3.

Microbiologically Influenced Corrosion of Fe3Al/ZrO2 Composites in Marine Environment

2009 ◽  
Vol 79-82 ◽  
pp. 2251-2254
Author(s):  
Xue Ting Chang ◽  
Shou Gang Chen ◽  
Yan Sheng Yin
Keyword(s):  
Passive Film ◽  
Polarization Curve ◽  
Potentiodynamic Polarization ◽  
Electrochemical Impedance ◽  
High Hardness ◽  
Impedance Spectrum ◽  
Microbiologically Influenced Corrosion ◽  
Electrochemical Impedance Spectrum ◽  
Potentiodynamic Polarization Curve ◽  
Corrosion Resistant

Electrochemical impedance spectrum (EIS) and potentiodynamic polarization curve were applied to invest the corrosive behavior of Fe3Al/ZrO2 composites with different components in marine microbial medium. The results indicated that the existence of microbiology negatively moved the open circle potential. When the composites contained 30% (wt %) ZrO2, the passive film on electrodes surface was the thickest one, even after 25 days the material was still protected. When the content of ZrO2 was 90%, Fe3Al was in the least content, after 25 days the passive film has disappeared, but the material was still not eroded because of the high hardness and corrosion-resistant properties of ZrO2. When the content of ZrO2 was 80%, the passive film was partly damaged, which could lead to more serious local corrosion.

scholarly journals Corrosion Resistance of Some Stainless Steels in Chloride Solutions

2017 ◽  
Vol 62 (2) ◽  
pp. 711-714
Author(s):  
D. Kasprzyk ◽  
B. Stypuła
Keyword(s):  
Corrosion Resistance ◽  
Pitting Corrosion ◽  
Stainless Steels ◽  
Potentiodynamic Polarization ◽  
Biomedical Application ◽  
Corrosion Behaviour ◽  
Immersion Test ◽  
Ringer Solution ◽  
Ferritic Stainless Steels ◽  
Chloride Solutions

AbstractThe present work compares corrosion behaviour of four types of S30403, S31603, S32615 austenitic and S32404 austenitic-ferritic stainless steels in chloride solutions (1%, 3% NaCl) and in Ringer solution, at 37°C temperature. Corrosion resistance was determined by potentiodynamic polarization measurements and a thirty day immersion test conducted in Ringer solution. The immersion test was performed in term of biomedical application. These alloy were spontaneously passivated in all electrolytes, wherein S30403, S31603 and S32404 undergo pitting corrosion. Only S32615 containing 5.5% Si shows resistance to pitting corrosion.

scholarly journals The Effect of Heat Treatment on Microstructure, Microhardness and Pitting Corrosion of Ti6Al4V Produced by Electron Beam Melting Additive Manufacturing Process

2021 ◽  
Author(s):  
Mingzhen Xiu ◽  
Yong Teck Tan ◽  
Srinivasan Raghavan ◽  
Min Hao Goh ◽  
Mui Ling Sharon Nai
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Electron Beam ◽  
Pitting Corrosion ◽  
Corrosion Behaviour ◽  
Corrosion Properties ◽  
Clear Trend ◽  
Pitting Potential ◽  
Pitting Corrosion Resistance ◽  
Lath Width

Abstract There has been limited studies on corrosion behaviour of post-processed Electron Beam Melted (EBM) Ti6Al4V, given that the factors affecting corrosion resistance of AM Ti6Al4V remain unclear. This paper proposes using heat treatment method to improve the pitting corrosion resistance of EBM Ti6Al4V. Different treatment profiles alter the microstructure of EBM Ti6Al4V. A clear trend is observed between microhardness and α lath width. As-printed EBM Ti6Al4V exhibits an inferior pitting potential, while heat treatment provided a significant improvement in the corrosion resistance. This study finds that the β phase fraction is a better indicator than the α lath width for pitting corrosion resistance. Solution air-cooled & ageing heat treated EBM Ti6Al4V exhibits good mechanical and corrosion properties, and even performs better than commercial cast Ti6Al4V.

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
Keyword(s):  
Anodic Dissolution ◽  
Sodium Carbonate ◽  
Pitting Corrosion ◽  
Passive Layer ◽  
Ion Concentration ◽  
Halide Ions ◽  
Pitting Potential ◽  
X Ray ◽  
Carbonate Concentration ◽  
Tin Anode

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.

Influence of MoSi2 Addition in Co Based Alloy Cladding Coating on Microstructure Evolution and Pitting Corrosion Behaviour

2013 ◽  
Vol 456 ◽  
pp. 392-398
Author(s):  
Ze Fen Liang ◽  
Min Zheng
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Pitting Corrosion ◽  
Stainless Steel Substrate ◽  
Corrosion Behaviour ◽  
Steel Substrate ◽  
304 Stainless Steel ◽  
Pitting Potential ◽  
Pitting Corrosion Resistance ◽  
Coating Microstructure

In the present paper the influence of the addition of MoSi2particles on the microstructure and pitting corrosion behaviour of laser cladding Co based alloy coatings deposited on 304 stainless steel substrate has been reported. The coating microstructure was investigated by SEM, OM, XRD and EPMA etc.. And the pitting corrosion resistance of coating was evaluated in the 3.5% NaCl solution. The results showed that: (1) The microstructure is fined by increasing MoSi2percentage. And the coating microstructure evolved from dendrites and interdendritic eutectics to various faceted dendrites with the bamboo leaf, flower, or butterfly morphology, when the MoSi2content is from 0~20% to 30~40%; (2) the (Epit-Eprot) of Co based alloy/MoSi2composite coating was lower than that of Co based alloy, and which presented higher self-repairing capability. The pitting potential Epitof Co +(0~20wt.%) MoSi2cladding coatings is higher than that of stainless steel, the pitting corrosion resistance is enhanced; When more MoSi2(30wt.%) was added, the pitting corrosion resistance decreases due to microstructure inhomogeneity and exiting of inclusion.

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