Determination of the concentration dependent diffusion coefficient of nitrogen in expanded austenite

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Abstract

The concentration dependent diffusion coefficient of nitrogen in expanded austenite was determined from of the rate of retracting nitrogen from thin initially N-saturated coupons. Nitrogen saturated homogeneous foils of expanded austenite were obtained by nitriding AISI 304 and AISI 316 in pure ammonia at 693 K and 718 K. Denitriding experiments were performed by equilibrating the foils with a successively lower nitrogen activity, as imposed by a gas mixture of ammonia and hydrogen. The concentration dependent diffusion coefficient of nitrogen in expanded austenite was approximated in the composition range where nitrogen can be extracted by hydrogen gas at the diffusion temperature. Numerical simulation of the denitriding experiments shows that the thus determined concentration dependent diffusion coefficients are an accurate approximation of the actual diffusivity of nitrogen in expanded austenite.
Original languageEnglish
JournalInternational Journal of Materials Research
Volume99
Issue number9
Pages (from-to)999-1005
ISSN1862-5282
DOIs
Publication statusPublished - 2008

Cite this

@article{4d43198ca08f40f9bf68f6ee79a81981,
title = "Determination of the concentration dependent diffusion coefficient of nitrogen in expanded austenite",
abstract = "The concentration dependent diffusion coefficient of nitrogen in expanded austenite was determined from of the rate of retracting nitrogen from thin initially N-saturated coupons. Nitrogen saturated homogeneous foils of expanded austenite were obtained by nitriding AISI 304 and AISI 316 in pure ammonia at 693 K and 718 K. Denitriding experiments were performed by equilibrating the foils with a successively lower nitrogen activity, as imposed by a gas mixture of ammonia and hydrogen. The concentration dependent diffusion coefficient of nitrogen in expanded austenite was approximated in the composition range where nitrogen can be extracted by hydrogen gas at the diffusion temperature. Numerical simulation of the denitriding experiments shows that the thus determined concentration dependent diffusion coefficients are an accurate approximation of the actual diffusivity of nitrogen in expanded austenite.",
author = "Thomas Christiansen and Somers, {Marcel A. J.}",
year = "2008",
doi = "10.3139/146.101729",
language = "English",
volume = "99",
pages = "999--1005",
journal = "International Journal of Materials Research",
issn = "1862-5282",
publisher = "Carl Hanser Verlag GmbH & Co. KG",
number = "9",

}

Determination of the concentration dependent diffusion coefficient of nitrogen in expanded austenite. / Christiansen, Thomas; Somers, Marcel A. J.

In: International Journal of Materials Research, Vol. 99, No. 9, 2008, p. 999-1005.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Determination of the concentration dependent diffusion coefficient of nitrogen in expanded austenite

AU - Christiansen, Thomas

AU - Somers, Marcel A. J.

PY - 2008

Y1 - 2008

N2 - The concentration dependent diffusion coefficient of nitrogen in expanded austenite was determined from of the rate of retracting nitrogen from thin initially N-saturated coupons. Nitrogen saturated homogeneous foils of expanded austenite were obtained by nitriding AISI 304 and AISI 316 in pure ammonia at 693 K and 718 K. Denitriding experiments were performed by equilibrating the foils with a successively lower nitrogen activity, as imposed by a gas mixture of ammonia and hydrogen. The concentration dependent diffusion coefficient of nitrogen in expanded austenite was approximated in the composition range where nitrogen can be extracted by hydrogen gas at the diffusion temperature. Numerical simulation of the denitriding experiments shows that the thus determined concentration dependent diffusion coefficients are an accurate approximation of the actual diffusivity of nitrogen in expanded austenite.

AB - The concentration dependent diffusion coefficient of nitrogen in expanded austenite was determined from of the rate of retracting nitrogen from thin initially N-saturated coupons. Nitrogen saturated homogeneous foils of expanded austenite were obtained by nitriding AISI 304 and AISI 316 in pure ammonia at 693 K and 718 K. Denitriding experiments were performed by equilibrating the foils with a successively lower nitrogen activity, as imposed by a gas mixture of ammonia and hydrogen. The concentration dependent diffusion coefficient of nitrogen in expanded austenite was approximated in the composition range where nitrogen can be extracted by hydrogen gas at the diffusion temperature. Numerical simulation of the denitriding experiments shows that the thus determined concentration dependent diffusion coefficients are an accurate approximation of the actual diffusivity of nitrogen in expanded austenite.

U2 - 10.3139/146.101729

DO - 10.3139/146.101729

M3 - Journal article

VL - 99

SP - 999

EP - 1005

JO - International Journal of Materials Research

JF - International Journal of Materials Research

SN - 1862-5282

IS - 9

ER -