Potentiodynamic behaviour of the nickel electrode in acid media

Rehim, Sayed S. Abd El; Wahaab, S.M. Abd El; Meguid, E. A. Abd El

doi:10.1016/0257-8972(86)90005-8

Cited by 12 publications

(3 citation statements)

References 21 publications

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“…The presence of two peaks on the polarization curve indicates a complex mechanism of the material passivation process resulting from the formation of several corrosion products. Nickel oxides NiO and Ni 3 O 4 [87,88], as well as hydroxides Ni(OH) 2 [89,90], can appear on the surface of nickel during corrosion in sulfuric acid solution. The content of 25 at.% Al does not significantly alter the mechanism of passive layer formation, but its importance is visible in the area of transpassivation.…”

Section: Analysis Of Corrosion Behaviormentioning

confidence: 99%

Corrosion Resistance of Nickel-Aluminum Sinters Produced by High-Pressure HPHT/SPS Method

et al. 2023

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As part of extensive research on the properties of nickel-aluminum alloys, corrosion tests of sintered materials produced by the innovative HPHT/SPS (high pressure, high temperature/spark plasma sintering) method were performed in 0.1 molar H2SO4 acid. The hybrid, unique device used for this purpose (one of only two such devices operating in the world) is equipped with a Bridgman chamber, which allows heating with high-frequency pulsed current and sintering of powders under high pressure in the range of 4–8 GPa and at temperatures up to 2400 °C. Using this device for the production of materials contributes to the generation of new phases not obtainable by classical methods. In this article, the first test results obtained for the nickel-aluminum alloys never before produced by this method are discussed. Alloys containing 25 at.% Al, 37 at.% Al and 50 at.% Al were produced. The alloys were obtained by the combined effect of the pressure of 7 GPa and the temperature of 1200 °C generated by the pulsed current. The time of the sintering process was 60 s. The electrochemical tests, such as OCP (open circuit potential), polarization tests and EIS (electrochemical impedance spectroscopy), were carried out for the newly produced sinters and the results were compared with the reference materials, i.e., nickel and aluminum. The corrosion tests showed good corrosion resistance of the produced sinters, with corrosion rates of 0.091, 0.073 and 0.127 mm per year, respectively. It leaves no doubt that the good resistance of materials synthesized by powder metallurgy is due to the proper selection of the manufacturing process parameters, ensuring a high degree of material consolidation. This was further confirmed by the examinations of microstructure (optical microscopy and scanning electron microscopy) and the results of density tests (hydrostatic method). It has been shown that the obtained sinters were characterized by a compact, homogeneous and pore-free structure, though at the same time differentiated and multi-phase, while the densities of individual alloys reached a level close to the theoretical values. The Vickers hardness of the alloys was 334, 399 and 486 HV10, respectively.

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Section: Analysis Of Corrosion Behaviormentioning

confidence: 99%

Corrosion Resistance of Nickel-Aluminum Sinters Produced by High-Pressure HPHT/SPS Method

et al. 2023

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“…Some outhers using open circuit potential to study corrosion. The effect of some organic inhibitors, namely, (acridine, benzyl quinolinium chloride, dodecyl quinolinium-bromide, tributyl benzyl ammonium iodide and potassium iodide) had been studied using open circuit potential [23]. It is shown from the inhibition process that it occurred when associated with lower free energy than that was in the corrosion process.…”

Section: Variation Of the Open Circuit Electrode Potential Of Zn In Sodium Phosphate Containing Aggressive Ions In Absence And Presence Omentioning

confidence: 99%

Chemical Behavior And Corrosion Inhibition Of Zinc Electrode In Phosphate Solutions Under Open Circuit Conditions

Wanees

Atef

2014

The International Conference on Chemical and Environmental Engi

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The electrochemical behavior of zinc electrode has been studied in different concentrations of Na 3 PO 4 .12H 2 O solution using a simple potentiometric method. The study involves the measurement of the electrode potentials under open-circuit conditions. The potential was followed as a function of both time and Na 3 PO 4 .12H 2 O solution concentration until the values of steady-state potential are obtained. The steady potential changed on the addition of increasing amounts of different aggressive anions due to the breakdown of passivity. The way of variation of the steady-state potentials of zinc electrode in aggressive solutions upon the addition of increasing quantities of some inhibitors as the type of inorganic inhibitors are also concerned. The potential shifts towards more positive values the addition of inhibitors and the potential curves recall those reported in aggressive anion-free solution indicating pitting corrosion. The micrograph of zinc surface in presence of different concentrations of aggressive ions was investigated using Scanning Electron Microscope SEM.

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“…In dilute sulfuric acid solutions (-<I0-3M), the formation of an oxide film on the electrode slows the dissolution of nickel. 4 The corrosion superiority of alloys as compared to pure metals is due to the presence of a compact oxide film. With increasing Cr content, the anodic dissolution rate of Ni-based alloys in I-I2SO4 solutions decreases ~ and the critical current density (iorit) falls sharply as the Cr content increases to about 14%, 6 after which the decrease of i~t levels off.…”

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confidence: 99%

Passivation of Iron‐Based Alloys in Para‐Toluene Sulfonic Acid

Yang¹,

Teng²

1993

J. Electrochem. Soc.

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Potentiodynamic and surface analysis techniques were applied to investigate the passivation of metals in para-toluene sulfonic acids (PTSA). The diffusion-limiting current density was used to calculate the ferrous ion concentration which causes the precipitation of a pseudopassive film. From the surface analysis data, the Cr/Fe ratio in the passive film increases in order of 430, 304, and 316 stainless steels. To analyze the differences, a correction was made to the data so that the observed difference in the oxide film composition is not attributed simply to the Cr and Fe contents of the alloys. This method also was applied to correct the Ni/Fe ratio in the passive film. We conclude that the preferential dissolution of Ni and Fe leads to a Cr enrichment in the passive film.

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Potentiodynamic behaviour of the nickel electrode in acid media

Cited by 12 publications

References 21 publications

Corrosion Resistance of Nickel-Aluminum Sinters Produced by High-Pressure HPHT/SPS Method

Corrosion Resistance of Nickel-Aluminum Sinters Produced by High-Pressure HPHT/SPS Method

Chemical Behavior And Corrosion Inhibition Of Zinc Electrode In Phosphate Solutions Under Open Circuit Conditions

Passivation of Iron‐Based Alloys in Para‐Toluene Sulfonic Acid

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