Kinetics of the passivation of molybdenum in acids and alkali solutions as inferred from impedance and potential measurements

Badawy, W. A.; Gad‐Allah, A. G.; El-Rahman, H. A. Abd; Abou-Romia, M. M.

doi:10.1016/0257-8972(86)90129-5

Cited by 32 publications

(13 citation statements)

References 8 publications

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“…These small periods of time were invisible in the diagram. At these high current densities the metal is susceptible to dissolution and electropolishing rather than passivation; the soluble product may be molybdate or molybdic acid (30,28) . On the other hand at 50 µAcm -2 , the presence of compounds 12AB and 12ABB in different weight percentages soluble in 0.01M HCl solution shifted the stabilized potential to more positive values ( Figure 2, a and b).…”

Section: Galvanostatic Polarization Measurementsmentioning

confidence: 99%

“…Several different electrochemical techniques were used to study the redox reaction in an aqueous acid solution at molybdenum oxide film electrode (26)(27)(28)(29)(30) . In H 2 SO 4 and acidic sulphate solutions, steady state polarization curves exhibit a two-Tafel slope suggesting the concurrence of two parallel reaction paths (31,32) .…”

Section: Introductionmentioning

confidence: 99%

“…In H 2 SO 4 and acidic sulphate solutions, steady state polarization curves exhibit a two-Tafel slope suggesting the concurrence of two parallel reaction paths (31,32) . The oxide film formed in H 2 SO 4 , H 3 PO 4 , HCl and Na 2 SO 4 is highly stable and the stability was attributed to its compact and non-defective structure (28) . Also, the passive films undergo structural changes during the course of measurements which may be attributed to a further oxidation of the passive MoO 2 film to MoO 3 (29) .…”

Section: Introductionmentioning

confidence: 99%

“…The oxide film formed in H 2 SO 4 , H 3 PO 4 , HCl and Na 2 SO 4 is highly stable and the stability was attributed to its compact and non-defective structure (28) . Also, the passive films undergo structural changes during the course of measurements which may be attributed to a further oxidation of the passive MoO 2 film to MoO 3 (29) . The aim of this work is to study the effect of 12AB and 12ABB on the corrosion of molybdenum in 0.01 M HCl solution with different polarization methods.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Two Triazole Thione Derivatives on Corrosion Behavior of Molybdenum in 0.01M HCL

Attia

2008

Al-Azhar Bulletin of Science

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4N-(2-hydroxy-3-triethyl ammonio-propyl-) fatty-1, 2, 4 triazole-3-thione (12AB) and 2,4N-(bis-2-hydroxy-3-triethyl ammonio-propyl-) fatty-1, 2, 4 triazole-3-thione (12ABB) were synthesized, characterized and tested as surfactant corrosion inhibitors for Mo in 0.01 M HCl solution using galvanostatic, potentiodynamic and potentiostatic polarization techniques. Concentrations of the inhibitors were ranged from 1x10 −6 to 1 (wt. %). The obtained results using galvanostatic polarization on bare metal showed that thickness of adsorbed layer decreased with increasing concentration of 12AB while adverse trend was observed with 12ABB. On the other hand the anodic oxide film formed at 100mAcm-2 up to 0.268V (SCE) was susceptible to a dissolution process with the presence of two corrosion rates for each concentration of the two additives. Potentiodynamic polarization illustrated that increase of additive concentration lowered corrosion current densities affecting anodic reaction more than cathodic one. The protection efficiency increased with increasing inhibitor concentration. The low values of IE. % indicated the presence of electrostatic attraction between inhibiting molecules and the electrically charged surface of metal. Adsorption followed the kinetic thermodynamic model, Langmuir and Flory-Huggins adsorption isotherms. 12ABB showed better inhibiting action than that of 12AB due to the presence of two side chains in its structure. Potentiostatic polarizations indicated that when the concentration of the additives 12AB and 12ABB exceeded a critical value, ≥0.1Wt.%, no inhibition effect.

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Section: Galvanostatic Polarization Measurementsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of Two Triazole Thione Derivatives on Corrosion Behavior of Molybdenum in 0.01M HCL

Attia

2008

Al-Azhar Bulletin of Science

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“…There are several papers describing a linear correlation of the potential increase and the logarithm of time [7,8,9]. This has been correlated with the growth of a surface layer by the "dissolution-precipitationmechanism" [10] as well as by the "high-field-mechanism" [11 -14].…”

Section: Interpretation Of Corrosion Datamentioning

confidence: 99%

Electrochemical Corrosion Experiments on Uranium Dioxide Pellets with Respect to a German ”Direct Repository”

Heppner¹,

Wegen²,

Marx

1992

Radiochimica Acta

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Investigations into the corrosion behaviour of U0 2 electrodes have been carried out in saturated salt solutions. The corrosion behaviour of the U0 2 electrodes is affected by the composition of the solutions, by pH value and by the redox conditions. Cabrine produces the highest corrosion rates which are even higher than in simulated groundwater. Experiments on the free corrosion potential were accompanied by electrochemical impedance spectroscopy. The results indicate an influence of the diffusion current on the potential adjustment, as well as the built-up and change of surface layers on the U0 2 electrodes.

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Electrocatalytic Activity and Stability Enhancement through Preferential Deposition of Phosphide on Carbide

et al. 2017

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Phosphides and carbides are among the most promising families of materials based on earth‐abundant elements for renewable energy conversion and storage technologies such as electrochemical water splitting, batteries, and capacitors. Nickel phosphide and molybdenum carbide in particular have been extensively investigated for electrochemical water splitting. However, a composite of the two compounds has not been explored. Here, we demonstrate preferential deposition of nickel phosphide on molybdenum carbide in the presence of carbon by using a hydrothermal synthesis method. We employ the hydrogen evolution reaction in acid and base to analyze the catalytic activity of phosphide‐deposited carbide. The composite material also shows superior electrochemical stability in comparison to unsupported phosphide. We anticipate that the enhanced electrochemical activity and stability of carbide deposited with phosphide will stimulate investigations into the preparation of other carbide–phosphide composite materials.

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Kinetics of the passivation of molybdenum in acids and alkali solutions as inferred from impedance and potential measurements

Cited by 32 publications

References 8 publications

Effect of Two Triazole Thione Derivatives on Corrosion Behavior of Molybdenum in 0.01M HCL

Effect of Two Triazole Thione Derivatives on Corrosion Behavior of Molybdenum in 0.01M HCL

Electrochemical Corrosion Experiments on Uranium Dioxide Pellets with Respect to a German ”Direct Repository”

Electrocatalytic Activity and Stability Enhancement through Preferential Deposition of Phosphide on Carbide

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