Electrochemical studies on pitting corrosion of tin in sodium borate solutions containing nitrate ions

2019 ◽  
Vol 66 (3) ◽  
pp. 300-306
Author(s):  
Nobl Foad El Boraei ◽  
Sayed S. Abd El Rehim ◽  
Hamdy H. Hassan
Keyword(s):  
Pitting Corrosion ◽  
Electrochemical Behavior ◽  
Nitrate Solution ◽  
Ion Concentration ◽  
Sodium Borate ◽  
Pitting Potential ◽  
Content Type ◽  
Pitting Corrosion Resistance ◽  
Passive Transition ◽  
Passive Oxide Film

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.

Pitting corrosion of super martensitic stainless steel 00Cr13Ni5Mo2

2014 ◽  
Vol 61 (6) ◽  
pp. 387-394 ◽  
Author(s):  
J.L. Li ◽  
C.T. Qu ◽  
S.D. Zhu ◽  
L. Liu ◽  
Z.Q. Gao
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Pitting Corrosion ◽  
Martensitic Stainless Steel ◽  
Pitting Potential ◽  
Content Type ◽  
Pitting Corrosion Resistance ◽  
Super Martensitic Stainless Steel ◽  
The Difference ◽  
Made In

Purpose – The purpose of this study was to investigate the pitting resistance and assess the critical pitting temperature (CPT) of a super martensitic stainless steel, 00Cr13Ni5Mo2, made in China, considering especially the difference in the pitting corrosion resistance between the domestic super martensitic stainless steel and an imported one. Design/methodology/approach – Potentiodynamic sweep tests were applied to investigate the effects of four NaCl concentrations (weight per cent) of 1, 3.5, 9 and 17, and four testing temperatures of 30, 50, 75 and 90°C on the pitting resistance of the domestic super martensitic stainless steel in the presence of CO2. Potentiostatic sweep tests were utilized to determine the CPT. Furthermore, chemical immersion exposures, implemented according to the appropriate standard were used to evaluate the difference in the pitting corrosion resistance between the domestic super martensitic stainless steel and an imported one. In addition, the morphology of pits was analyzed using a scanning electron microscope. Finding – The pitting potential of the domestic super martensitic stainless steel decreased with an increase in NaCl concentration and temperature in the presence of CO2. The CPT of the domestic super martensitic stainless steel measured by potentiostatic polarization was 41.16°C. Two types of typical corrosion pits, closed pits formed at 35°C and open pits formed at 50°C, were observed. Furthermore, compared to the super martensitic stainless steel made in Japan, the domestic one was better in terms of pitting potential, corrosion rate and the density of the pits, but worse in terms of the depth of the pits, which may result in a risk of corrosion perforation of tubing and casings. Originality/value – The paper highlights that chloride ions, temperature and the presence of CO2 play an important role on the pitting resistance of super martensitic stainless steel.

Effect of Cl- Concentration on Pitting Corrosion Property of Maraging Hardened Stainless Steel Based on Pourbaix Diagram

2018 ◽  
Vol 940 ◽  
pp. 59-64 ◽  
Author(s):  
Xin Zhang ◽  
De Ning Zou ◽  
Yu Qing Zhou ◽  
Xuan Na ◽  
Wei Zhang ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Pitting Corrosion ◽  
Corrosion Potential ◽  
Corrosion Current ◽  
Corrosion Property ◽  
Ion Concentration ◽  
Pitting Potential ◽  
Pitting Corrosion Resistance ◽  
The Matrix ◽  
Simulation Results

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.

Influence of Sigma Phase Precipitation on Pitting Corrosion of 2507 Super-Duplex Stainless Steel

2010 ◽  
Vol 658 ◽  
pp. 380-383 ◽  
Author(s):  
Ying Han ◽  
De Ning Zou ◽  
Wei Zhang ◽  
Jun Hui Yu ◽  
Yuan Yuan Qiao
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Ambient Temperature ◽  
Duplex Stainless Steel ◽  
Pitting Corrosion ◽  
Super Duplex Stainless Steel ◽  
Phase Precipitation ◽  
Pitting Potential ◽  
Σ Phase ◽  
Pitting Corrosion Resistance

Specimens of 2507 super-duplex stainless steel aging at 850°C for 5 min, 15 min and 60 min were investigated to evaluate the pitting corrosion resistance in 3.5% NaCl solution at 30°C and 50°C. The results are correlated with the microstructures obtained with different aging time. The precipitation of σ phase remarkably decreases the pitting corrosion resistance of the steel and the specimen aged for 60 min presents the lowest pitting potential at both 30°C and 50°C. With increasing the ambient temperature from 30°C to 50°C, the pitting potential exhibits a reduction tendency, while this tendency is less obviously in enhancing the ambient temperature than in extending the isothermal aging duration from 5 to 60 min. SEM analysis shows that the surrounding regions of σ phase are the preferable sites for the formation of corrosion pits which grew up subsequently. This may be attributed to the lower content of corrosion resistance elements in these regions formatted with σ phase precipitation.

scholarly journals Pitting Corrosion Resistance on Annealing Treated Super Duplex Stainless Steel S32750

Crystals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 294
Author(s):  
Shuang Liu ◽  
Chaohua Yue ◽  
Xi Chen ◽  
Qiuhua Zhu ◽  
Yiyou Tu
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Duplex Stainless Steel ◽  
Pitting Corrosion ◽  
Annealing Temperature ◽  
Super Duplex Stainless Steel ◽  
Boundary Area ◽  
Pitting Potential ◽  
Pitting Corrosion Resistance ◽  
Equivalent Number

The pitting corrosion resistance of S32750 super duplex stainless steel, annealing treated at temperatures of 950–1200 °C for 20–60 min, was investigated using potentiodynamic polarization tests. The results show that the volume fractions of ferrite in the S32750 duplex stainless steel increased from 48.9% to 68.4% as annealing temperatures increased from 950 to 1200 °C. The pitting potential of the sample increased first and then decreased from an annealing temperature of 950 to 1050 °C, and the highest pitting potential was observed after annealing at 1050 °C for 35 min. The pitting corrosion resistance of S32750 stainless steel is due to the combination of pitting resistance equivalent number (PREN) value, phase fraction and grain boundary area fraction, and the imbalance of corrosion potential.

Corrosion evaluation of Ti-6Al-4V parts produced with electron beam melting machine

2016 ◽  
Vol 22 (2) ◽  
pp. 322-329 ◽  
Author(s):  
Dana H. Abdeen ◽  
Bruce R. Palmer
Keyword(s):  
Electron Beam ◽  
Corrosion Behavior ◽  
Pitting Corrosion ◽  
Electron Beam Melting ◽  
Saturated Calomel Electrode ◽  
Nacl Solution ◽  
Pitting Potential ◽  
Exterior Surface ◽  
Content Type ◽  
Critical Pitting Temperature

Purpose This paper aims to evaluate the corrosion behavior of Ti-6Al-4V parts produced with electron beam melting (EBM) machine and compare it with wrought Ti-6Al-4V alloy. Design/methodology/approach Potentiodynamic and potentiostatic tests were applied on EBM Ti-6Al-4V in 3.5 per cent mass NaCl solution to determine the pitting potential and critical pitting temperature (CPT). A relation between pitting potential and temperature was established for EBM Ti-6Al-4V alloy by conducting potentiodynamic testing under different temperatures. CPT was also measured for EBM Ti-6Al-4V alloy in 3.5 per cent mass NaCl solution at a standard potential of 800 mV vs saturated calomel electrode (SCE). The same tests were performed on wrought Ti-6Al-4V for comparison purposes. Moreover, CPT for EBM Ti-6Al-4V alloy was measured in 3.5 per cent mass NaCl solution of different pH of 2.0, 5.7 and 10.0 to examine the effect of aggressive conditions on the pitting corrosion of EBM alloy. Findings Potentiodynamic test resulted in a relatively high pitting potential of EBM alloy, which was close to the pitting potential of wrought alloy even at higher temperatures. In addition, EBM samples did not pit when potentiostatic test was performed at 800 mV vs SCE, even at high and low values of pH. Originality/value EBM Ti-6Al-4V alloy has been increasingly playing an important role in aerospace, automobile and industrial fields. The technique and conditions of manufacturing form voids and increase roughness of the exterior surface of EBM objects, which might increase the tendency to initiate pitting corrosion within its holes and surface folds. This article shows that, despite surface variations and porosity in EBM Ti-6Al-4V alloy, the material maintained its corrosion resistance. It was found that the corrosion behavior of EBM alloy was close to that of the conventionally made wrought Ti-6Al-4V alloy.

Effect of Chloric Ions and Temperature on the Pitting Corrosion Behavior of Supermartensitic Stainless Steel in CO2-Saturated Chloride Solution

2012 ◽  
Vol 538-541 ◽  
pp. 2342-2345
Author(s):  
Jun Li ◽  
Dong Ye ◽  
Yong Mei Chen ◽  
Jie Su ◽  
Kun Yu Zhao
Keyword(s):  
Stainless Steel ◽  
Corrosion Behavior ◽  
Pitting Corrosion ◽  
Chloride Solution ◽  
Polarization Measurement ◽  
Ion Concentration ◽  
Pitting Potential ◽  
Supermartensitic Stainless Steel ◽  
Different Temperatures ◽  
Logarithmic Relation

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.

Modelling input data interactions for the optimization of artificial neural networks used in the prediction of pitting corrosion

2019 ◽  
Vol 66 (4) ◽  
pp. 369-378
Author(s):  
Mohamed Nadir Boucherit ◽  
Sid Ahmed Amzert ◽  
Fahd Arbaoui ◽  
Yakoub Boukhari ◽  
Abdelkrim Brahimi ◽  
...  
Keyword(s):  
Neural Networks ◽  
Corrosion Resistance ◽  
Artificial Neural Networks ◽  
Pitting Corrosion ◽  
Input Data ◽  
Corrosion Inhibitors ◽  
Experimental Program ◽  
Pitting Potential ◽  
Content Type ◽  
Artificial Neural

Purpose This paper aims to predict the localized corrosion resistance by the application of artificial neural networks. It emphasizes the importance to take into account the relationships between the physical parameters before presenting them to the network. Design/methodology/approach The work was conducted in two phases. At the beginning, the authors executed an experimental program to measure pitting corrosion resistance of carbon steel in an aqueous environment. More than 900 electrochemical experiments were conducted in chemical solutions containing different concentrations of pitting agents, corrosion inhibitors and oxidant reagents. The obtained results were collected in a table where for a combination of the experimental parameters corresponds a pitting potential Epit obtained from the corresponding electrochemical experiment. In the second step, the authors used the experimental data to train different artificial neuron networks for predicting pitting potentials. Findings In this step, the authors considered the relationships that the chemical parameters are likely to have between them. Two types of relationships were taken into account: chemical equilibria which are controlled by the pH and the synergistic relationships that some corrosion inhibitors may have when they are in the presence of a chemical oxidant. Originality/value This comparative study shows that adjusting the input data by considering the physical relationships between them allows a better prediction of the pitting potential. The quality of the prediction, quantified by a regression factor, is qualitatively confirmed by a statistical distribution of the gap between experimental and calculated pitting potentials.

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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