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AbstractAbstract
[en] Diffusion in α brasses has been investigated using methods involving the evaporation and the condensation of zinc. Having shown that at sufficiently high temperatures intergranular diffusion has no effect, it was then proved that the rate of evaporation or of condensation can only be defined if the mechanical treatment of the test piece before diffusion, the direction of the diffusion and the nature of the impurities present are also defined. The coefficient of diffusion D is then given by the equation D (π/4t)ρ20 where t is the duration of the diffusion; ρ0 is the extrapolated value of ρ = (Δm)/(ΔC) for a zero value of the variation of concentration (Δm in is the change in weight of the test piece per unit surface; ΔC is the difference between the concentration at the surface and the initial concentration of the test piece). This method has been used to study the effect of the direction of the diffusion on the coefficient of diffusion. The coefficient for diffusion which decreases the concentration of zinc is 5 times greater than that for diffusion which increases the quantity of zinc in the metal; an interpretation of this phenomena based on the mechanism of diffusion vacancies in the structure has been proposed. By means of micrographic investigation and by weighing it has been shown that the presence of certain impurities, such as phosphorous, arsenic, antimony, silicon, and aluminium can result in a marked increase of the rate of diffusion: the effect of these impurities on the coefficient of diffusion has been related to their valency and atomic weight. (author)
[fr]
La diffusion dans les laitons α a ete etudiee au moyen des methodes d'evaporation et de condensafion du zinc. Apres avoir montre qu'aux temperatures suffisamment elevees, la diffusion intergranulaire ne jouait aucun role, l'auteur a prouve que la vitesse d'evaporation ou de condensation n'est definie que dans la mesure ou sont precises: les traitements mecaniques subis par l'eprouvette avant diffusion, le sens de la diffusion, la nature des eprouvettes. Le coefficient de diffusion D est alors donne par la relation: D = (π/4t)ρ20 expression dans laquelle t est la duree de diffusion et ρ0 la valeur extrapolee de ρ = (Δm)/(ΔC) a variation nulle de concentration; (Δm, variation de poids de l'eprouvette par unite de surface; ΔC, difference entre la concentration superficielle et la concentration initiale de l'eprouvette). Cette methode a ete utilisee pour etudier l'influence du sens de diffusion sur le coefficient de diffusion le coefficient de diffusion avec appauvrissement en zinc est 5 fois plus grand que le coefficient de diffusion avec enrichissement en zinc;une interpretation de ce phenomene, basee sur le mecanisme lacunaire de diffusion a ete proposee. Par une etude ponderale et une etude micrographique, l'auteur a montre que certaines impuretes, telles que le phosphore, l'arsenic, l'antimoine, le silicium et l'aluminium peuvent augmenter notablement la vitesse de diffusion; il a relie a la valence et a la masse atomique des impuretes, l'influence de celles-ci sur le coefficient de diffusion. (auteur)Original Title
Etude de la diffusion dans les laitons ∝ au moyen des methodes d'evaporation ou de condensation du zinc
Primary Subject
Source
1959; 11 p; Symposium on Solid State Diffusion; Colloque sur la diffusion a l'etat solide; Saclay (France); 3-5 Jul 1958; 15 refs.
Record Type
Report
Literature Type
Conference
Report Number
Country of publication
ALLOYS, BRASS, COPPER ALLOYS, COPPER BASE ALLOYS, CRYSTAL DEFECTS, CRYSTAL STRUCTURE, DIMENSIONLESS NUMBERS, ELEMENTS, METALS, MICROSTRUCTURE, NEUTRAL-PARTICLE TRANSPORT, PHASE TRANSFORMATIONS, PHOTOGRAPHY, PHYSICAL PROPERTIES, POINT DEFECTS, RADIATION TRANSPORT, THERMODYNAMIC PROPERTIES, TRANSITION ELEMENT ALLOYS, ZINC ALLOYS
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