Corrosion Behavior of Pb-Ca-Sn Electrodes for Copper Electrowinning

2011 ◽  
Vol 402 ◽  
pp. 349-353
Author(s):  
Xue Tao Yuan ◽  
Xu Dong Lv ◽  
Zhi Qiang Hua ◽  
Lei Wang ◽  
Tao Li
Keyword(s):  
Corrosion Rate ◽  
Ternary Alloy ◽  
Corrosion Behavior ◽  
Current Density ◽  
Potentiodynamic Polarization ◽  
Electrode Surface ◽  
Anodic Polarization ◽  
Polarization Measurements ◽  
Copper Electrowinning ◽  
Sn Anode

Anodic polarization behavior of ternary alloy Pb-0.08%Ca-1%Sn is studied by potentiodynamic polarization measurements, corrosion rate, the products on electrode surface after polarization, and microstructure of anode mud after polarization in electrowinning cell. The results show that Pb-Ca-Sn anode is easy to be passivated in electrolyte for copper electrowinning, the maintaining passivity current density is 97.72 µA•cm-2and the corrosion products on the surface of Pb-Ca-Sn electrode present loose scaly, being composed of α-PbO2, β- PbO2and PbSO4after polarization.

scholarly journals Corrosion Behavior of AlFeCrCoNiZrx High-Entropy Alloys in 0.5 M Sulfuric Acid Solution

Metals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1471
Author(s):  
Yuhong Yao ◽  
Yaohua Jin ◽  
Wei Gao ◽  
Xiaoyu Liang ◽  
Jian Chen ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Rate ◽  
Corrosion Behavior ◽  
Potentiodynamic Polarization ◽  
General Corrosion ◽  
High Entropy Alloys ◽  
H2so4 Solution ◽  
High Entropy ◽  
Polarization Measurements ◽  
Selective Corrosion

AlCoCrFeNiZrx (x = 0, 0.1, 0.2, 0.3, and 0.5) high-entropy alloys (HEAs) were prepared by a non-consumable vacuum arc melting technology, and the microstructure and corrosion behavior were investigated by XRD, SEM, immersion tests, and electrochemical measurements. The results indicate that galvanic corrosion of the AlCoCrFeNiZrx alloys occurred in 0.5 M H2SO4 solution, and only 0.1 mol of the added Zr could greatly improve the corrosion resistance of the alloys. The corrosion properties of the AlCoCrFeNiZrx HEAs had similar change tendencies with the increase in the Zr content in the immersion tests, potentiodynamic polarization measurements, and electrochemical impedance analysis, that is, the corrosion resistance of the AlCoCrFeNiZrx alloys in a 0.5 M H2SO4 solution first increased and then decreased with the increase in the Zr content. The Zr0.1 alloys were found to have the best selective corrosion and general corrosion resistance with the smallest corrosion rate, whereas the Zr0.3 alloys presented the worst selective corrosion and general corrosion resistance with the highest corrosion rate from both the immersion tests and the potentiodynamic polarization measurements.

Effect of hydrogen on semiconductor properties and pitting initiation of 2205 duplex stainless steel passivation film

2020 ◽  
Vol 67 (3) ◽  
pp. 313-320 ◽  
Author(s):  
Chuanbo Zheng ◽  
Jiayan Huang ◽  
Gua Yi
Keyword(s):  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Passive Film ◽  
Corrosion Behavior ◽  
Current Density ◽  
Anodic Polarization ◽  
Content Type ◽  
2205 Duplex Stainless Steel ◽  
Passivation Film ◽  
Semiconductor Properties

Purpose This paper aims to study the effect of current density of hydrogen charging on the semiconductor properties and pitting initiation of 2205 duplex stainless steel (DSS) passivation film. Design/methodology/approach In this work, the 2205 DSS is pre-hydrogenated and passivated. Then, the passivation film is tested by electrochemical impedance method, Mott–Schottky curve method and dynamic potential scanning method. The influences of hydrogen on the properties of the passivation film and the corrosion behavior of the matrix were studied by analyzing the curves obtained in the electrochemical test. The surface of the passivation film after pre-hydrogenation and anodic polarization was observed by using the ultra-depth three-dimensional microscopy and the scanning electron microscope. The integrity, density and corrosion morphology of the passivation film were studied and discussed. Findings With the increase of the hydrogen current density, the growth of the passivation film is hindered, the concentrations of donor and acceptor in the film are increased, the conductivity of the passivation film increases. In the anodic polarization, the dimensional passive current density increases with the increase of the hydrogen current density, and the pitting potential is reversed, the more likely the sample is pitting. In general, hydrogen hinders the formation of the passive film on duplex stainless steel, which increases the concentration of point defects in the passive film. Finally, the passive film is easy to crack and pitting. Originality/value The performance of passive film is an important condition to influence the corrosion behavior of stainless steel. However, little research has been done on the effects of hydrogen on the electrochemistry and pitting sensitivity of 2205 DSS passivation films. The effect of hydrogen on semiconductor properties and pitting initiation of 2205 DSS passivation film is needed to be investigated.

Corrosion Behavior of Al-Sn-Bi Alloys in Ethylene Glycol-Water Mixtures

CORROSION ◽  
2012 ◽  
Vol 68 (5) ◽  
pp. 421-431
Author(s):  
J.L. Gama-Ferrer ◽  
J.G. Gonzalez-Rodriguez ◽  
I. Rosales ◽  
J. Uruchurtu
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Corrosion Rate ◽  
Ethylene Glycol ◽  
Corrosion Behavior ◽  
Potentiodynamic Polarization ◽  
Electrochemical Noise ◽  
Electrochemical Impedance ◽  
Electrochemical Techniques ◽  
Potentiodynamic Polarization Curves

A study of the effect of Sn (1, 2, 3.5, 4.5, and 5 wt%) and Bi (0.5, 1.5, 3, and 4%) on the corrosion behavior of Al in ethylene glycol (C2H6O2)-40% water mixtures at 20, 40, and 60°C has been carried out using electrochemical techniques. Techniques include potentiodynamic polarization curves, electrochemical impedance spectroscopy (EIS), and electrochemical noise (EN) measurements. The three techniques have shown that additions of either Sn or Bi contents increased the corrosion rate of pure Al in all cases, and that generally speaking, the corrosion rate increased by increasing the temperature except for the alloy containing 1% Sn + 4% Bi, which showed the lowest corrosion rate at 60°C. This was because of a galvanic effect from the presence of Sn and/or Bi particles on the surface alloy, which acted as local cathodes, leading to an acceleration of corrosion. Nyquist diagrams showed two semicircles at 20°C and only one at 40°C or 60°C for all the alloys, showing two different corrosion-controlling mechanisms. EN measurements showed evidence of a mixture of both localized and uniform types of corrosion for all Al-based alloys.

scholarly journals ELECTROCHEMICAL STUDIES FOR CORROSION INHIBITION OF MILD STEEL BY CHRYSOPHYLLUM ALBIDUM EXTRACT

2018 ◽  
Vol 6 (1) ◽  
pp. 415-420
Author(s):  
Akoma Chigozie ◽  
Osarolube Eziaku ◽  
Abumere O. E.
Keyword(s):  
Corrosion Rate ◽  
Mild Steel ◽  
Current Density ◽  
Potentiodynamic Polarization ◽  
Mixed Type ◽  
Inhibition Efficiency ◽  
Electrochemical Studies ◽  
Polarization Technique ◽  
Carbonated Drinks

The corrosion behavior of mild steel in carbonated drinks produced by Nigerian Breweries (Fanta, Sprite and Coke) was studied in the presence and absence of an eco-friendly inhibitor, Chrysophyllum albidum using Potentiodynamic polarization technique at 25 °C. Results showed that Chrysophyllum albidum reduced the current density (icorr), which in turn means that the corrosion rate was reduced significantly. The inhibition efficiency was found to be 93%, 78.6% and 87.5% for Fanta, Sprite and Coke respectively. The study also showed that Chrysophyllum albidum functioned as a mixed-type corrosion inhibitor in the three environments studied and therefore presents it as a long-term inhibitor for the corrosion of mild steel.

scholarly journals Effects of Surface Preparation on the Corrosion Behavior of Mild Steel

2021 ◽  
Vol 29 (1) ◽  
pp. 16-25
Author(s):  
Wasiu Ayoola ◽  
Stephen Durowaye ◽  
Kenneth Andem ◽  
Olujide Oyerinde ◽  
Jesutofunmi Ojakoya
Keyword(s):  
Quantitative Analysis ◽  
Corrosion Rate ◽  
Mild Steel ◽  
Corrosion Behavior ◽  
Potentiodynamic Polarization ◽  
Surface Preparation ◽  
Uncoated Sample ◽  
Engineering Materials ◽  
Subsequent Failure ◽  
Effect Of Surface

Surface preparation of engineering materials is necessary for preventing corrosion and subsequent failure of materials in service. There are different methods of surface preparations that can affect engineering materials in different ways. This study investigated the effect of surface preparation on the corrosion behavior of zinc sprayed and unsprayed mild steel. Quantitative analysis and potentiodynamic polarization techniques were used to evaluate the immersed samples of different surface preparations. The results indicated that the least corrosion rate was observed for the uncoated sample prepared with CC1200 grit paper at 0.041 mpy and successive samples in the order of CC220 grit paper at 0.047 mpy < P60 grit paper at 0.052 mpy < filing at 0.064 mpy and grinding at 0.074 mpy after 42-days of immersion. The prepared samples that were further coated with zinc spray demonstrated a similar trend. The sample prepared with CC1200 grit paper and further coated with zinc spray exhibited the lowest corrosion rate of 1.35 x 10-9 mpy. Potentiodynamic polarization results further suggested that the same behavior was observed in the quantitative analysis.

Corrosion Behavior of Super Austenitic Stainless Steel 904L Weldment in Sulfuric Acid Media Used for Leaching Application

2020 ◽  
Vol 835 ◽  
pp. 384-391 ◽  
Author(s):  
Gamal M. Rashed ◽  
Waleed A. Mohrez ◽  
Abd Allah M. Abd El-Hamid ◽  
Ibrahim M. Ghayad
Keyword(s):  
Weight Loss ◽  
Sulfuric Acid ◽  
Corrosion Rate ◽  
Acid Solution ◽  
Corrosion Behavior ◽  
Potentiodynamic Polarization ◽  
Total Immersion ◽  
Polarization Test ◽  
Super Austenitic Stainless Steel ◽  
Leaching Medium

This article reports the corrosion behavior of 904L weldment in sulfuric acid as a strong corrosive media. The corrosion behavior was studied by total immersion tests and potentidynamic polarization test. Total immersion test has been conducted at different acid concentrations typically: 1, 2, 4, 6, 8 and 18.4 M at 25°C. The effect of temperature (25- 100°C) on the weight loss measurements of the alloy samples was followed in the 4 M acid solution. On the other hand, potentiodynamic polarization tests were conducted in 2,5, 8 and 18.4 M H2SO4 solution. The potentiodynamic polarization test was also conducted in the practically used leaching medium (2 M H2SO4 + 10% monazite).Results show that the weight loss increases with the increase of acid concentration and reaches its maximum at 4 M H2SO4 and then gradually decreases. Meanwhile, the rise in temperatures results in the increase of weight loss. Potentiodynamic polarization tests indicate that the 5 M acid solution gives the highest corrosion rate of 0.6399 mm/Y. The leaching medium shows relatively higher corrosion rate (0.124 mm/y) than the corresponding 2 M H2SO4 without monazite (0.01712 mm/y).

Studies on the Influence of Chloride Ion Concentration on the Corrosion Behavior of ZSMX Magnesium Alloy

2010 ◽  
Vol 95 ◽  
pp. 47-50 ◽  
Author(s):  
Guy Ben-Hamu ◽  
D. Eliezer ◽  
Kwang Seon Shin
Keyword(s):  
Magnesium Alloy ◽  
Corrosion Rate ◽  
Corrosion Behavior ◽  
Potentiodynamic Polarization ◽  
Electrochemical Behavior ◽  
Chloride Ion ◽  
Ion Concentration ◽  
Experimental Techniques ◽  
Nacl Solution ◽  
Wrought Magnesium Alloy

The paper presented reveals the influence of chloride ion concentration on the corrosion and electrochemical behavior of new ZSMX wrought magnesium alloy in NaCl solution. The experimental techniques used include potentiodynamic polarization tests. The corrosion rate usually increased with the increase in chloride ion concentration. This result can be explained by the distribution of intermetalics.

Electrochemical evaluation of cr-mn austenitic stainless steel in aqueous sulphuric acid and influence of thiocyanate ions

2020 ◽  
Vol 67 (3) ◽  
pp. 281-293 ◽  
Author(s):  
Ankur V. Bansod ◽  
Awanikumar P. Patil ◽  
Sourabh Shukla
Keyword(s):  
Stainless Steel ◽  
Sulfuric Acid ◽  
Corrosion Rate ◽  
Acid Solution ◽  
Corrosion Behavior ◽  
Potentiodynamic Polarization ◽  
Steel Surface ◽  
Content Type ◽  
Polarization Test ◽  
Increasing Temperature

Purpose Low nickel austenitic stainless steel (ASS) has attracted much attention worldwide because of its economical price. This study aims to investigate the effect of different corrosive environments on the corrosion behavior of chrome-manganese (Cr-Mn) ASS. The tests were carried out as a function of H2SO4 concentrations, temperature and addition of ammonium thiocyanate (NH4SCN) (0.01 M). Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques were used to study the corrosion behavior of Cr-Mn ASS. It was observed that with increasing H2SO4 concentration, temperature and with the addition of NH4SCN solution, icorr, icrit and ipassive values increased. EIS data show decreasing charge transfer resistance value with increasing concentration and temperature. Higher corrosion rate with increasing temperature and concentration of H2SO4 is related to the anions (SO42−), which is responsible for reducing the stability of passive films. With the presence of 0.01 M NH4SCN thiocyanate (SCN− anion), there is a higher dilution of the passive film resulting in a higher corrosion rate. Energy-dispersive spectroscopy (EDS) analysis reveals the adsorption of sulfur on the surface in NH4SCN containing a solution. The significant presence of counter ions and the adsorbed sulfur species on the steel surface play a vital role in corrosion behavior. Design/methodology/approach All the experiments were performed on a 3 mm thick sheet of Cr-Mn ASS (202 ASS) in hot rolled condition. The samples were then annealed at 1,050°C for 1 h, followed by water quenching. For microstructural examination, they were electrochemically etched in 10 Wt.% oxalic acid solution at 1 amp for 90 s. A computer-controlled Potentiostat (Biologic VMP-300) was used. After the cell was set up, the working electrode (WE) was electrostatically cleaned at −1 V vs saturated calomel electrode (SCE) for 30 s to remove the air-formed film. Then, WE were allowed to attain stable open circuit potential (OCP) for 1 h, following by the EIS test and potentiodynamic polarization test. The polarization test was started from a cathodic potential (−1.2 V vs SCE) and continued up to an anodic potential (1.6 V vs SCE) a scan rate of 0.1667 mV/s. EIS experiment was conducted on the same instrument by using a sinusoidal AC signal of 10 mV in a frequency range of 1,000,000 to 0.01 Hz at OCP. Findings Potentiodynamic polarization graph shows that with the increase in sulphuric acid concentration. Increasing temperature from 20°C to 80°C in 0.5 M H2SO4 solution increases the corrosion rate (icorr) of Cr-Mn ASS. On the addition of 0.01 M NH4SCN to the sulfuric acid solution (0.1, 0.5 and 1 M) the corrosion rate increases drastically almost four to five times. EDS and XRD analysis shows the presence of sulfur over the oxide film and preferential site for dissolution of Cr and Mn at the steel surface when NH4SCN is added to the sulfuric acid solution. Originality/value A study on the corrosion behavior of Cr-Mn ASS is scanty according to the author’s knowledge. Therefore, the present study will investigate the corrosion behavior of Cr-Mn ASS on SO4−2 anions, temperature and the addition of SCN− ion in sulfuric acid.

scholarly journals Effects of Crystallization on the Corrosion and Passivity of Amorphous Pd-Fe-Co-Si-B Alloys

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
HeeJin Jang ◽  
Han-Ok Lee ◽  
Hyun-Goo Kim
Keyword(s):  
Amorphous Alloy ◽  
Corrosion Rate ◽  
Corrosion Behavior ◽  
Potentiodynamic Polarization ◽  
Alloy Composition ◽  
Buffer Solution ◽  
Donor Density ◽  
Crystalline Alloy ◽  
Current Densities ◽  
Passive Current

Corrosion behavior of Pd48.2Fe17Co16.7Si13.4B4.7 and Pd51.4Fe18Co18Si11.1B1.5 alloys was examined by potentiodynamic polarization tests in pH 8.5 buffer solution. The amorphous alloy ribbons showed passivity with the passive current densities of 2 × 10−6 A/cm2~4 × 10−6 A/cm2. The crystalline alloys showed a higher corrosion rate in pH 8.5 buffer solution with the degree of variation depending on the alloy composition. It is suggested from the Mott-Schottky analysis that the donor density was lower for the amorphous alloy than the crystalline alloy.

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