Cathodic polarization behaviour of Nb-Ni alloys in a concentrated KOH solution

Sugimoto, Katsuhisa; Bélanger, G.; Piron, D. L.

doi:10.1016/0376-4583(79)90047-5

Cited by 5 publications

(5 citation statements)

References 6 publications

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“…Le principal probleme que l'on rencontre avec les alliages du niobium est la degradation de la surface pour les materiaux entre 20 et 30% de Co ou Ni (5,6). Pour les alliages de plus forte teneur en Co, la stabilite s'accroit mais au detriment de l'activite Clectrocatalytique.…”

Section: Discussion Et Conclusionunclassified

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Polarisation cathodique en milieu alcalin des alliages Nb–Co

Umetsu¹,

Piron²,

Bélanger³

1981

Can. J. Chem.

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NbCo alloys were prepared and their composition characterized by optical microscopy. These alloys were evaluated for their electrochemical activity towards the hydrogen evolution reaction (HER) at 25 °C in a 25% KOH solution. The alloys between 20 and 70wt% Co showed an increased activity compared to their parent metals. However the activity is below the one observed for pure Ni. As for the NbNi alloys, the NbCo undergo some surface degradation under prolonged (6 h) cathodic polarization at 400–700 mA cm−2. This disintegration of the surfaces is observed for alloys below 50% in Co. Above this proportion, the alloys remain stable towards the RDH. This degradation is associated with the presence of the δ phase in the alloy: this phase is the solid solution of Nb in the alloy.

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Section: Discussion Et Conclusionunclassified

“…Aprks refroidissement et solidification, le l'klectrolvse de l'eau en milieu alcalin. le niobium a bouton d'alliage ainsi forme a ete retourne et refondu pour kt6 ktudik par notre groupe (1)(2)(3)(4)(5). L~ &canisme du assurer une homog6neit6 complkte a l'etat solide de I'alliage.…”

Section: Introductionunclassified

Polarisation cathodique en milieu alcalin des alliages Nb–Co

Umetsu¹,

Piron²,

Bélanger³

1981

Can. J. Chem.

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“…The high solubility of hydrogen in the glassy alloy is not surprising since both its components form hydrides: up to NbH2.nT (40) and a distinct NiHo.~ phase (41) can be formed electrochemically. Crystalline 10Ni-9ONb and 31Ni-69Nb are also hydrogen embrittled by cathodic polarization in 25% KOH (11); the spalled surface layers produced by 20 days' immersion at the free corrosion potential had the composition Nbtt0.s9 (12).…”

Section: E1 E~mentioning

confidence: 99%

“…Glassy Cu-Zr (6), Ti-Ni (7), and A1-Fe (8) have been investigated, and there is only one brief report on glassy (109-x)Ni-xNb (9). (11,12) in 25 weight percent (w/o) KOH. (10) in 3M HC1 and 1M I-t2SO~ and by Sugimoto etal.…”

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confidence: 99%

The Electrochemistry of Glassy 60Ni‐40Nb in Aqueous Media

Grant

Archer

1984

J. Electrochem. Soc.

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The electrochemistry of glassy melt-spun 60 atom percent (a/o) Ni-40 a/o Nb was investigated at moderate temperatures in various aqueous media. The alloy was very corrosion resistant to most acids and alkalis, but it was attacked by aqueous HF. Cyclic voltammograms of the glassy alloy in 15M NaOH indicated the existence of a thin nickel oxide corrosion layer from which niobium was absent. Linear sweep vottammetry in the oxygen evolution region, constant current chronopotentiometry, and rest potential decay measurements confirmed that the alloy surface in alkali consisted of nickel oxides. Chronopotentiometry in 0.5M H2SO4 at 30~ indicated the formation of a thin niobium oxide corrosion film which did not prevent oxygen evolution. Anodization in concentrated neutral KC1 caused severe corrosion. On cathodization in acid, the glassy alloy absorbed ca. 14 a/o hydrogen and was severely embrittled. Attempted hydrogen permeation experiments caused ribbon fracture; as-quenched and low temperature-annealed glasses behaved differently in this respect. * Electrochemical Society Active Member. Key words; glassy metal, NI-Nb alloy. ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 130.126.162.126 Downloaded on 2015-03-14 to IP ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 130.126.162.126 Downloaded on 2015-03-14 to IP Vol. 13I, No. 5 GLASSY 60Ni-40Nb 1001 ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 130.126.162.126 Downloaded on 2015-03-14 to IP ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 130.126.162.126 Downloaded on 2015-03-14 to IP

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“…Dans cette presente etude, nous avons etendu Dans le cadre des travaux de notre groupe sur la traVaux Pour evaluer le comPortement anorkaction du degagement de 19hydrogkne (RDH), dique des alliages Co-Nb en milieu alcalin; les une de mesures furent realisees illustrant observations klectrochimiques ont ete compl~ties certains avantages Clectrocatalytiques du niobium Par l'evaluation par spectroscopic Auger de la (1-3) et ses alliages avec le Ni (4,5). En effet, lors composition chimique de la surface a~r k s une d'une polarisation cathodique, le niobium acquiert polarisation anodique prolongee.…”

Section: Introductionunclassified

Comportement anodique des alliages Nb–Co en milieu alcalin

Umetsu¹,

Baillon²,

Piron³

et al. 1981

Can. J. Chem.

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Niobium–cobalt alloys are stable to corrosion in an open circuit in the presence of oxygen in 25% KOH solution as long as the weight percentage of cobalt exceeds 50%. Below this value, samples submitted to these conditions disintegrate after 30 days. When these alloys are submitted to anodic polarization an active dissolution is noted followed by passivation and in the presence of cobalt production of oxygen occurs. Electronic Auger Spectroscopic (EAS) analysis of pure niobium and its alloys with 30% and 90% cobalt indicates that the oxide film grows in an irregular manner according to the nature of the surface. Thus, for an identical anodic polarization (0.845 V vs. ENH for 6 hours) the oxide film changes from 4.13 × 10−2 μm for pure Nb to 0.10 μm for the 30% Co–Nb alloy and becomes as thin as 8 × 10−4 μm for the 90% Co–Nb alloy. The concentration profile as shown by EAS indicates a preferential dissolution of Nb over Co in the oxide film. [Journal translation]

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Cathodic polarization behaviour of Nb-Ni alloys in a concentrated KOH solution

Cited by 5 publications

References 6 publications

Polarisation cathodique en milieu alcalin des alliages Nb–Co

Polarisation cathodique en milieu alcalin des alliages Nb–Co

The Electrochemistry of Glassy 60Ni‐40Nb in Aqueous Media

Comportement anodique des alliages Nb–Co en milieu alcalin

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