Nitrogen diffusion in a subsurface region of ion-implanted molybdenum

Zamalin, E. Yu.; Bodnar, O.B.

doi:10.1134/1.1383836

Cited by 2 publications

(1 citation statement)

References 3 publications

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“…Significant (>2‰) equilibrium isotopic fractionation between the solid phases (phases 2, 3, and 4) may be excluded as the temperature of the system far exceeded the range in which observable nitrogen isotopic fractionation is expected (<700°C) [ Richet et al , 1977; Urey , 1947]. Estimates for the diffusivity of nitrogen (solid solution) in Mo are high enough (8.9 × 10 −5 to 9.8 × 10 −2 cm 2 /s [ Zamalin and Bodnar , 2001, and reference therein]) at 1800°C to allow effective diffusive exchange for the experimental timescale.…”

Section: Discussion: Possible Processes and Effects On The Analyticalmentioning

confidence: 99%

Fast chemical and isotopic exchange of nitrogen during reaction with hot molybdenum

Yokochi

Marty

2006

Geochem Geophys Geosyst

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[1] Molybdenum crucibles are commonly used to extract nitrogen from geological samples by induction heating. Because nitrogen is known to be reactive with certain metals (e.g., Ti and Fe), we have tested the reactivity of gaseous nitrogen with a Mo crucible held at 1800°C. The consumption of nitrogen, determined by monitoring the N 2 / 40 Ar ratio of the gas phase, varied between 25 and 100%, depending on the reaction duration. Nitrogen of the reacted gas was found to be systematically enriched in 15 N relative to 14 N by 10% compared to the initial isotopic composition, without any correlation with nitrogen consumption. We propose that a rapid isotopic exchange occurs between nitrogen originally trapped in the crucible and nitrogen from the gas phase, which modifies the isotopic composition of the reacted gas. This process can significantly bias the isotopic determination of nitrogen in rocks and minerals when a Mo furnace is used for gas extraction. Meanwhile, the rate of N-Mo chemical bonding may be controlled by the formation of nitride (rather than solid solution), a process slower than the isotopic exchange. The use of a Mo furnace for the extraction of trace nitrogen from rocks and minerals should therefore be avoided.

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Section: Discussion: Possible Processes and Effects On The Analyticalmentioning

confidence: 99%

Fast chemical and isotopic exchange of nitrogen during reaction with hot molybdenum

Yokochi

Marty

2006

Geochem Geophys Geosyst

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Non-Destructive Method of Diffusion Parameters Determination in Solids

Bodnar

Аристова

Mazilkin

et al. 2005

DDF

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Diffusion of nitrogen implanted in tungsten and molybdenum single crystals has been investigated at temperature about 0.3 Tm (Tm is the melting point). Existence of several dopant atom fluxes is found in subsurface region of the ion implanted material. The diffusion coefficients of the nitrogen connected with the radiation damages and that with the bulk diffusion mechanism are determined. Change of the nitrogen surface concentration has been measured by Auger electron spectroscopy. Initial distribution of the nitrogen and diffusion profiles for various annealing time have been determined by secondary-ion mass-spectroscopy technique. Transmission electron microscopy and X-ray diffraction investigations were used to study the microstructure and phase state of the implanted samples.

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Nitrogen diffusion in a subsurface region of ion-implanted molybdenum

Cited by 2 publications

References 3 publications

Fast chemical and isotopic exchange of nitrogen during reaction with hot molybdenum

Fast chemical and isotopic exchange of nitrogen during reaction with hot molybdenum

Non-Destructive Method of Diffusion Parameters Determination in Solids

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