Effect of composition on the formation and thermal stability of Ni72(Mo, Co)8B20 metallic glass

Graydon, J. W.; Thorpe, Steven J.; Kirk, Donald W.

doi:10.1016/0956-7151(94)00371-n

Cited by 8 publications

(4 citation statements)

References 37 publications

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“…A similar type of shoulder has also been found in many other glasses e.g. Fe 80 B 20 (Greer 1982), Al 75 Cu 15 V 10 (Holzer and Kelton 1991) and Ni 72 Mo 2 Co 6 B 20 (Graydon et al 1995). It was reported that the shoulder found for Fe 80 B 20 glass was due to delayed crystallization for the 10% of the ribbon nearest to the wheel, and, when crystallized, this portion showed the identical phases as were found in the bulk of the glass (Greer 1982).…”

Section: Resultssupporting

confidence: 82%

Effect of high-energy heavy ion irradiation on the crystallization kinetics of Co-based metallic glasses

et al. 2001

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Differential scanning calorimeter (DSC) is employed to study the crystallization kinetics of irradiated (at three different fluences with high-energy heavy ion; Ni 11+ of 150 MeV) specimens of two Co-based metallic glasses. It is found that the crystallization process in both the glasses is completed in two phases. The DSC data have been analysed in terms of kinetic parameters viz. activation energy (E c), Avrami exponent (n), dimensionality of growth (m), using two different theoretical models. The results obtained have been compared with that of virgin samples. The lower activation energy in case of second crystallization occurring at higher temperature indicates the easier nucleation of second phase. The abnormally high value of Avrami exponent in Co-Ni glass indicates very high nucleation rate during first crystallization.

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Section: Resultssupporting

confidence: 82%

Effect of high-energy heavy ion irradiation on the crystallization kinetics of Co-based metallic glasses

et al. 2001

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“…2 is around 1.2 nm. This value is very comparable to the Scherrer's length found for amorphous metal alloys such as the Ni-Mo-Co-B alloys examined by Graydon et al 9 Identification of deposit compound.-Spot elemental analysis by EDX at different locations of the deposit samples ͑plate and powder͒ showed a homogeneous composition. The deposits from both electrode materials have vanadium as the major component, a substantial amount of potassium ͑and sodium for the deposit on Ni͒, and trace amounts of iron and calcium.…”

Section: Resultssupporting

confidence: 83%

Characterization of Vanadium Deposit Formation at a Hydrogen Evolving Electrode in Alkaline Media

Abouatallah

Kirk

Thorpe

et al. 2001

J. Electrochem. Soc.

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Although nickel exhibits a high electrocatalytic activity toward the hydrogen evolution reaction, it undergoes extensive deactivation as a cathode during alkaline water electrolysis. The addition of dissolved V 2 O 5 to the electrolyte results in partial reactivation of nickel cathodes in 8 mol/L KOH at 70°C by formation of a vanadium-rich deposit. Various analytical techniques were employed to characterize the deposit in terms of surface morphology, phase analysis, and chemical composition. The deposit on nickel had a smooth and compact surface with a thickness of 1-2 m. X-ray diffraction results indicated an amorphous structure with a Scherrer's length less than 2 nm. Chemical and thermal analyses led to an empirical compound formula of K 2 H 2 V 10 O 26 •4H 2 O. That formula implied a mixed-valence (ϩ4/ϩ5) vanadium compound, later confirmed by X-ray photoelectron spectroscopy. The mechanism of deposit formation was then investigated by cyclic voltammetry on a mercury electrode. A cathodic peak representing the reduction of vanadium (ϩ5) species was apparent near the onset of hydrogen evolution on mercury. The behavior of the cathodic peak with concentration and sweep rate revealed key steps in the mechanisms of deposit formation. Deposit formation was modeled as an irreversible precipitation/polymerization reaction following a charge transfer step, to produce a large, mixedvalence vanadium compound.

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“…The shoulder on the low temperature side is possibly the manifestation of the early crystallization of amorphous material in the coating that was significantly reheated for a short period during successive passes of the spray gun whilst depositing multiple layers. Local reheating would allow the formation of pre-existing crystalline nuclei or relaxation of the amorphous state, as proposed by Graydon et al [27], which leads to a portion of the amorphous phase crystallizing at lower temperature. Local reheating during spraying and amorphous phase relaxation could also be the reason for the lower temperature of the second DSC peak in coating samples.…”

Section: Analysis Of Dsc Datamentioning

confidence: 95%

Microstructure evolution and thermal stability of an Fe-based amorphous alloy powder and thermally sprayed coatings

Chokethawai

McCartney

Shipway

2009

Journal of Alloys and Compounds

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Effect of composition on the formation and thermal stability of Ni72(Mo, Co)8B20 metallic glass

Cited by 8 publications

References 37 publications

Effect of high-energy heavy ion irradiation on the crystallization kinetics of Co-based metallic glasses

Effect of high-energy heavy ion irradiation on the crystallization kinetics of Co-based metallic glasses

Characterization of Vanadium Deposit Formation at a Hydrogen Evolving Electrode in Alkaline Media

Microstructure evolution and thermal stability of an Fe-based amorphous alloy powder and thermally sprayed coatings

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