Solute effects on solvent electromigration in dilute alloys

Doan, N.V.; Bocquet, J.L.

doi:10.1016/0040-6090(75)90239-4

Cited by 24 publications

(17 citation statements)

References 17 publications

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“…For several fcc metal alloys, the jump frequencies have been determined using a combination of data on the solute and solvent self-diffusion coefficients, measurements of the solvent atom diffusivity as a function solute concentration, measurements of the electromigration drift velocity as a function of solute concentration (Doan and Bocquet (1975), and measurements of the shift in position of inert markers in binary interdiffusion experiments (Kirkendall effect) (Allnatt and Lidiard, 1993;Bocquet et al, 1983). Currently we are aware of six cases where sufficient data exist to both calculate f using Eqs.…”

Section: Vacancy Mechanismmentioning

confidence: 99%

Theoretical constraints on the isotope effect for diffusion in minerals

Orman

Krawczynski

2015

Geochimica et Cosmochimica Acta

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Please cite this article as: Van Orman, J.A., Krawczynski, M.J., Theoretical constraints on the isotope effect for diffusion in minerals, Geochimica et Cosmochimica Acta (2015), doi: http://dx. ABSTRACTIsotopes of the same element generally diffuse at slightly different rates within a mineral, due to the difference in their masses. The magnitude of the mass dependence of the diffusion coefficient depends on the product of the correlation coefficient f (representing the degree to which the diffusion process deviates from a random walk) and the coupling coefficient K (representing the degree to which the motion of an atom during a single jump is coupled to that of other nearby atoms). Whereas K has been found to vary over a relatively narrow range, f can vary over a wide range from ~0 to 1.Diffusive isotope effects are expected to be large for trace and minor cations that diffuse slowly relative to the major cations that occupy the same sites and diffuse by the same mechanism. Diffusive isotope effects are also expected to be large for elements that diffuse rapidly by a simple interstitial mechanism. In both of these cases, the correlation coefficient is similar to or equal to unity. Diffusive isotope effects are reduced when the diffusion process is correlated, as for (1) rapid diffusion of trace and minor cations by a vacancy mechanism, with a low migration barrier for the jump to a vacancy; (2) diffusion by an interstitialcy process, or a process involving interstitial-vacancy pairs; (3) diffusion in grain boundaries and dislocations, where both dimensional restrictions and non-uniformity of the structure enhance correlation. The correlation coefficient can be determined from independent experimental data on the jump frequencies involved in the diffusion process, and/or from theoretical calculations of the jump energies. Quantitative estimates of the isotope effect are made for several cations in periclase, olivine, magnetite and rutile.

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Section: Vacancy Mechanismmentioning

confidence: 99%

Theoretical constraints on the isotope effect for diffusion in minerals

Orman

Krawczynski

2015

Geochimica et Cosmochimica Acta

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“…( b ) Variation du rapport LA&,, en fonction de u = w,/wo dans l'approximation 2 (interaction limithe aux premiers voisins). ((1) Doan et Bocquet (1975) …”

Section: Approximationunclassified

“…Pour les mBtaux c.c., il n'y a que deux rapports A calculer h partir de deux de ces grandeurs. Doan (1972) et Doan et Bocquet (1975) ont montre que la mesure du facteur b", qui d4crit l'influence de la concentration du solute sur la vitesse d'dlectromigration du solvant, et qui depend aussi des rapports de frdquence consider& ci-dessus, peut %re substituee B l'une des mesures classiques, en particulier & celle de f B qu'il n'est pas toujours possible d'effectuer.…”

Section: Q 1 Introductionunclassified

“…Par contre, on ne dispose actuellement que d'une expression approchee pour les C.C. (Doan et Bocquet 1975 Le calcul des coefficients Lij permet d'exprimer toutes les grandeurs qui apparaissent dans les phenomhnes de transport. Nous les calculons ici dans le cas de 1'8lectromigration dans un alliage &lu6 cubique centre demeurant homoghe, avec un mecanisme de diffusion lacunaire.…”

Section: Q 1 Introductionunclassified

“…Nous les calculons ici dans le cas de 1'8lectromigration dans un alliage &lu6 cubique centre demeurant homoghe, avec un mecanisme de diffusion lacunaire. Les Bquations (1) prennent alors la forme (Doan 1971) : oii ZAk:k et Z,* sont respectivement les valences efficaces du solvant e t du solut6, E le champ dlectriyue, T la temperature et e la valeur absolue de la charge de l'dlectron. Comme les coefficients phdnomenologiques Lij sont independant's des forces thermodynamiques Xi, le choix de forces particulihres mieux adaptdes au problkme dtudid ne limite en rien la g6n6ralit6 du resultat.…”

Section: Q 1 Introductionunclassified

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