Characterization by electrolyte electroreflectance and X-ray photoelectron spectroscopy of amorphous Ni59Nb40Pt1−Sn  alloys and their activation by HF solutions

Sistiaga, M.; Cuesta, Ángel; Pierna, A.R.; Gutiérrez, C.

doi:10.1016/s0039-6028(98)00330-6

Cited by 17 publications

(7 citation statements)

References 14 publications

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“…When the HF treatment is done, an attack of the external surface takes place. As a consequence the oxides of niobium and nickel are dissolved and an enrichment in platinum and tin occurs at the alloy surface [10], as well as an increment in the roughness of the electrode sur- face. This amorphous film is mainly composed by platinum and tin microparticles, which are homogeneously distributed due to the amorphous structure of the matrix.…”

Section: Discussionmentioning

confidence: 99%

Application of amorphous materials for fuel cells

Sistiaga

Pierna

2003

Journal of Non-Crystalline Solids

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Section: Discussionmentioning

confidence: 99%

Application of amorphous materials for fuel cells

Sistiaga

Pierna

2003

Journal of Non-Crystalline Solids

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“…All catalysts were activated by immersion in analytical grade HF 48% solution for 10 s at room temperature and rinsed out with distilled water. Previous studies [11] have concluded that the surface of these amorphous alloys consists mainly of nickel and niobium oxides, metallic nickel and metallic niobium. After the HF treatment superficial oxides are removed and the surface is mainly composed of Pt and co-catalyst elements, so the chemical activation generates active sites on the electrode surface.…”

Section: Methodsmentioning

confidence: 96%

“…Particularly, amorphous nickel alloys have a high corrosion resistance to several acids. Furthermore, these homogeneous solid solutions combined whith various elements, are excellent precursors for the preparation of alloys having a high electro-catalytic activity and selectivity [11,12].…”

mentioning

confidence: 99%

Co‐catalytic effect of Rh and Ru for the ethanol electro‐oxidation in amorphous microparticulated alloys

Blanco

Pierna

Barroso

2011

Phys. Status Solidi C

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The ethanol electro‐oxidation on platinum catalyst in acid media leads to the formation of acetaldehyde and acetic acid as main products. Another problem is the poisoning of the electro‐catalyst surface with CO formed during the fuel oxidation reaction. To increase the performance of Direct Ethanol Fuel Cells (DEFCs) it is necessary to develop new electrode materials or modification of the existing Pt catalysts. This work presents the electrochemical response to ethanol and CO oxidation of different compositional amorphous alloys obtained by ball milling technique, used as electrodes. Alloys with Ni59Nb40Pt0.6Rh0.4 and Ni59Nb40Pt0.6Rh0.2Ru0.2 composi‐tions were studied. The current density towards ethanol oxidation decreases with the presence of ruthenium; however, this electrode shows the best tolerance to CO, with lower surface coverage (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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“…From these ingots, amorphous alloy ribbons of ¾10 mm wide and 20-30 µm thickness were obtained by the planar flow casting method described in previous works. 5,6 The amorphous nature of the alloys was confirmed by x-ray diffraction and the compositions were determined by inductively coupled plasma (ICP). To produce microstructural changes, the samples were annealed isothermally at 400, 600 and 670°C in a quartz tube under an Ar atmosphere for different times.…”

Section: Methodsmentioning

confidence: 99%

Nanocrystallization process of the Fe69.5Cu1Nb3B9Si13.5Cr4 FINEMET-type alloy: an AFM study

Salinas¹,

García²,

Bessone³

et al. 2000

Surf. Interface Anal.

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The different devitrification stages of Fe 69.5 Cu 1 Nb 3 B 9 Si 13.5 Cr 4 (F-Cr4) amorphous alloy were studied by atomic force microscopy (AFM) on samples annealed at 400, 600 and 670°C for different treatment times. The AFM images showed no topographic changes in the alloys treated at 400°C, indicating that only structural relaxations took place at this annealing temperature. Samples thermally treated at 600°C showed hemispherical features uniformly distributed on the surface, suggesting initiation of the nanocrystallization process. The nanocrystals formed had a size distribution of 15-40 nm, which is slightly affected by the annealing time. At 670°C the crystallization phenomena occurred with the formation of large crystals and an increase in roughness. The corrosion behaviour of the nanocrystalline alloys in 2 M HCl solution was correlated with the AFM studies. The potentiodynamic experiments for these alloys showed a significant decrease of the current density peak at the active-passive transition in relation to the F-Cr4 amorphous alloy. The results indicated that the corrosion resistance and passivating ability of the alloys are improved by the thermal treatment.

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Characterization by electrolyte electroreflectance and X-ray photoelectron spectroscopy of amorphous Ni59Nb40Pt1−Sn alloys and their activation by HF solutions

Cited by 17 publications

References 14 publications

Application of amorphous materials for fuel cells

Application of amorphous materials for fuel cells

Co‐catalytic effect of Rh and Ru for the ethanol electro‐oxidation in amorphous microparticulated alloys

Nanocrystallization process of the Fe69.5Cu1Nb3B9Si13.5Cr4 FINEMET-type alloy: an AFM study

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