Abstract
Uranium samples of six different qualities were subjected, in the temperature range 400 - 1000 C, to the action of carbon dioxide carefully purified to eliminate oxygen and water vapour; the resulting oxidation was followed micro-graphically and also (but only in the range 400 - 700 C) gravimetrically using an Ugine-Eyraud microbalance. A comparison of the results leads to the following 3 observations. First, the oxidation of the six uraniums studied obeys a linear law, (followed at 700 C by an accelerating law). The rates of reaction differ by a maximum of 100 per cent, the higher purity grades being oxidized more slowly except at 700 C when the reverse is true. Secondly, simultaneously with the growth, of an approximately uniform film of uranium dioxide on the metal, there occurs a localized attack in the form of blisters in the immediate neighbourhood of the monocarbide inclusions in the uranium. The relative importance of this attack is greater for lower oxidation temperatures and for a larger size, number and inequality of distribution of the inclusions, that is to say for higher carbon concentrations in the uranium (which have values from 7 to 1000 ppm in our tests). Thirdly, for oxidation temperatures
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Desrues, R;
Paidassi, J
[1]
- Commissariat a l'Energie Atomique, Saclay (France). Centre d'Etudes Nucleaires
Citation Formats
Desrues, R, and Paidassi, J.
Comparative study of the oxidation of various qualities of uranium in carbon dioxide at high temperatures; Etude comparative de l'oxydation de diverses qualites d'uranium dans l'anhydride carbonique aux temperatures elevees.
France: N. p.,
1965.
Web.
Desrues, R, & Paidassi, J.
Comparative study of the oxidation of various qualities of uranium in carbon dioxide at high temperatures; Etude comparative de l'oxydation de diverses qualites d'uranium dans l'anhydride carbonique aux temperatures elevees.
France.
Desrues, R, and Paidassi, J.
1965.
"Comparative study of the oxidation of various qualities of uranium in carbon dioxide at high temperatures; Etude comparative de l'oxydation de diverses qualites d'uranium dans l'anhydride carbonique aux temperatures elevees."
France.
@misc{etde_20680261,
title = {Comparative study of the oxidation of various qualities of uranium in carbon dioxide at high temperatures; Etude comparative de l'oxydation de diverses qualites d'uranium dans l'anhydride carbonique aux temperatures elevees}
author = {Desrues, R, and Paidassi, J}
abstractNote = {Uranium samples of six different qualities were subjected, in the temperature range 400 - 1000 C, to the action of carbon dioxide carefully purified to eliminate oxygen and water vapour; the resulting oxidation was followed micro-graphically and also (but only in the range 400 - 700 C) gravimetrically using an Ugine-Eyraud microbalance. A comparison of the results leads to the following 3 observations. First, the oxidation of the six uraniums studied obeys a linear law, (followed at 700 C by an accelerating law). The rates of reaction differ by a maximum of 100 per cent, the higher purity grades being oxidized more slowly except at 700 C when the reverse is true. Secondly, simultaneously with the growth, of an approximately uniform film of uranium dioxide on the metal, there occurs a localized attack in the form of blisters in the immediate neighbourhood of the monocarbide inclusions in the uranium. The relative importance of this attack is greater for lower oxidation temperatures and for a larger size, number and inequality of distribution of the inclusions, that is to say for higher carbon concentrations in the uranium (which have values from 7 to 1000 ppm in our tests). Thirdly, for oxidation temperatures above 600 C blistering is much less pronounced, but at 700 C the beginning of a general deformation of the sample occurs, which, above 750 C, becomes much greater; this leads to an acceleration of the reaction rate with respect to the linear law. In view of the over-heating, the sample must already be in the {gamma}-phase which is particularly easily deformed; furthermore this expansion phenomenon is more pronounced when the sample is more plastic and therefore purer. (authors) [French] Des echantillons de six qualites d'uranium ont ete soumis, dans l'intervalle 400-1000 C, a l'action de l'anhydride carbonique tres soigneusement purifie en oxygene et en vapeur d'eau, et leur oxydation a ete suivie par voie micrographique et egalement (mais seulement entre 400 et 700 C) par voie gravimetrique. a l'aide d'une thermobalance Ugine-Eyraud. De la comparaison des resultats, les 3 points suivants ont pu etre degages. Premieremt une loi lineaire (suivie a 700 C d'une loi acceleree) regit l'oxydation des six uraniums etudies. Les vitesses de reaction different au plus d'environ 100 pour cent, les qualites les plus pures s'oxydant le plus lentement, sauf a 700 C ou l'inverse a lieu. Deuxiemement, en meme temps qu'un film de bioxyde d'uranium sensiblement uniforme croit sur le metal, une attaque localisee sous forme de pustules se produit au voisinage immediat des inclusions de monocarbure dans l'uranium. L'importance relative de cette derniere est d'autant plus grande que la temperature d'oxydation est plus basse et que le nombre, la taille et l'inegalite de distribution des inclusions sont plus grands, c'est-a-dire que la teneur en carbone de l'uranium (comprise entre 7 et 1000 ppm dans nos essais) l'est egalement. Troisiement, aux temperatures d'oxydation superieures a 600 C, les pustules retrogradent fortement, mais il apparait des 700 C un debut de deformation generale de l'echantillon qui, a partir de 750 C, s'agrandit considerablement, ce qui entraine une acceleration de la cinetique de reaction par rapport a la loi lineaire. Compte tenu de la surchauffe, l'echantillon doit alors deja se trouver en phase gamma qui est particulierement deformable; d'autre part cet effet de grandissement est d'autant plus accentue que le metal est plus plastique, donc plus pur.}
place = {France}
year = {1965}
month = {Jul}
}
title = {Comparative study of the oxidation of various qualities of uranium in carbon dioxide at high temperatures; Etude comparative de l'oxydation de diverses qualites d'uranium dans l'anhydride carbonique aux temperatures elevees}
author = {Desrues, R, and Paidassi, J}
abstractNote = {Uranium samples of six different qualities were subjected, in the temperature range 400 - 1000 C, to the action of carbon dioxide carefully purified to eliminate oxygen and water vapour; the resulting oxidation was followed micro-graphically and also (but only in the range 400 - 700 C) gravimetrically using an Ugine-Eyraud microbalance. A comparison of the results leads to the following 3 observations. First, the oxidation of the six uraniums studied obeys a linear law, (followed at 700 C by an accelerating law). The rates of reaction differ by a maximum of 100 per cent, the higher purity grades being oxidized more slowly except at 700 C when the reverse is true. Secondly, simultaneously with the growth, of an approximately uniform film of uranium dioxide on the metal, there occurs a localized attack in the form of blisters in the immediate neighbourhood of the monocarbide inclusions in the uranium. The relative importance of this attack is greater for lower oxidation temperatures and for a larger size, number and inequality of distribution of the inclusions, that is to say for higher carbon concentrations in the uranium (which have values from 7 to 1000 ppm in our tests). Thirdly, for oxidation temperatures above 600 C blistering is much less pronounced, but at 700 C the beginning of a general deformation of the sample occurs, which, above 750 C, becomes much greater; this leads to an acceleration of the reaction rate with respect to the linear law. In view of the over-heating, the sample must already be in the {gamma}-phase which is particularly easily deformed; furthermore this expansion phenomenon is more pronounced when the sample is more plastic and therefore purer. (authors) [French] Des echantillons de six qualites d'uranium ont ete soumis, dans l'intervalle 400-1000 C, a l'action de l'anhydride carbonique tres soigneusement purifie en oxygene et en vapeur d'eau, et leur oxydation a ete suivie par voie micrographique et egalement (mais seulement entre 400 et 700 C) par voie gravimetrique. a l'aide d'une thermobalance Ugine-Eyraud. De la comparaison des resultats, les 3 points suivants ont pu etre degages. Premieremt une loi lineaire (suivie a 700 C d'une loi acceleree) regit l'oxydation des six uraniums etudies. Les vitesses de reaction different au plus d'environ 100 pour cent, les qualites les plus pures s'oxydant le plus lentement, sauf a 700 C ou l'inverse a lieu. Deuxiemement, en meme temps qu'un film de bioxyde d'uranium sensiblement uniforme croit sur le metal, une attaque localisee sous forme de pustules se produit au voisinage immediat des inclusions de monocarbure dans l'uranium. L'importance relative de cette derniere est d'autant plus grande que la temperature d'oxydation est plus basse et que le nombre, la taille et l'inegalite de distribution des inclusions sont plus grands, c'est-a-dire que la teneur en carbone de l'uranium (comprise entre 7 et 1000 ppm dans nos essais) l'est egalement. Troisiement, aux temperatures d'oxydation superieures a 600 C, les pustules retrogradent fortement, mais il apparait des 700 C un debut de deformation generale de l'echantillon qui, a partir de 750 C, s'agrandit considerablement, ce qui entraine une acceleration de la cinetique de reaction par rapport a la loi lineaire. Compte tenu de la surchauffe, l'echantillon doit alors deja se trouver en phase gamma qui est particulierement deformable; d'autre part cet effet de grandissement est d'autant plus accentue que le metal est plus plastique, donc plus pur.}
place = {France}
year = {1965}
month = {Jul}
}