Published November 1963
| Version v1
Book
On the Formation of UC1-xOx and UC1-xNx
Description
From thermodynamical study it was inferred that UC1-xO-x would be in equilibrium with CO gas of 10-4 mm Hg at 1600 deg. C, if it exists. Compacted mixtures of UO2 and UC or UC2 in several compositions were reacted at 1200 deg. C, 1600 deg. C and 1750 deg. C in a vacuum of 10-4 mm Hg. The main phase after the reaction was identified as UC1-xOx , where x covered from 0 to 0.8 according to the initial composition ratio UO2-UC or UO2-UC2. The lattice parameter of UC1-xOx was found to be changed with heat treatments by a small amount, for example, about 0.2% at x = 0.7, which fact shows that there is a deviation from stoichiometric composition in UC1-xOx. The heat of formation of UC1-xOx was measured by the DTA (differential thermal analysis) method using the reaction: UC1-xOx +O2 → U3O8 + CO2 The condition of stable existence of UC1-xNx was also calculated from the free energies of formation of several compounds in the reaction system. The result showed that UC1-xNx, whose x is smaller than a value x' uniquely determined by the pressure of N2 and temperature, dissociates into UC1-x'Nx' and carbon or UC2 under the pressure and at the temperature. Whether the latter component is C or UC2 is determined also by the pressure of N2 and the temperature. Experiments on the reaction between U2N3 and C, the reaction between UC2 and N2, etc. were carried out under several different conditions in pressure and temperature. Good agreement was observed between the experimental result and thermodynamical calculation. (author)
Abstract (French)
L'etude thermodynamique avait permis d'etablir que UC1-xOx s'il existait, serait en equilibre avec CO, sous une pression de 10-4 mm de mercure et a une temperature de 1600 deg. C. On a fait reagir des melanges densifies de UC2 et de UC ou de UC2 de diverses com positions, a des temperatures de 1200 deg. C, 1600 deg. C et 1750 deg. C sous vide de 10-4 mm de mercure. On a constate qu'apres reaction la phase principale etait UC1-xOx, dans lequel x variait de 0 a 0,8 selon les proportions de UO2 et de UC ou de UO2 et de UC2 dans le melange initial. On a constate egalement que des traitements thermiques faisaient varier le parametre de reseau de UC1-xOx dans de petites proportions: de 0,2%, par exemple, lorsque x = 0,7, ce qui montre que UC1-xOx presente un ecart par rapport a la composition stoechiometrique. On a mesure la chaleur de formation de UC1-xOx par analyse thermique differentielle en utilisant la reaction: UC1-xOx +O2 → U3O8 + CO2. On a egalement determine, a partir des energies libres de formation de plusieurs composes dans le systeme reactionnel, a quelle condition UC1-xNx peut exister sous une forme stable. Les resultats ont montre que UC1-xNx, dans lequel x est inferieur a une valeur x' determinee uniquement par la pression de N2 et la temperature, se dissocie en UC1-x'Nx' et en carbone ou en UC2 sous la pression et a la temperature considerees. La pression de N2 et la temperature determinent egalement la nature du dernier composant: C ou UC2. On a procede a des experiences portant sur les reactions entre U2N3 et C, entre UC2 et N2, etc., dans diverses conditions de temperature et de pression. On a constate une concordance satisfaisante entre les resultats de ces experiences et les calculs thermodynamiques. (author)Abstract (Spanish)
Los autores dedujeron de sus estudios termodinamicos que el UC1-xOx se hallaria en equilibrio con el CO gaseoso, si dicho equilibrio existe, a una presion de 10-4 mm de Hg y a una temperatura de 1600 deg. C. Se han hecho reaccionar mezclas comprimidas de UO2 y UC o UC2, de diferente composicion, a 1200 deg. C, 1600 deg. C y 1750 deg. C, a una presion de 10-4 mm de Hg. Se ha observado que despues de la reaccion, la fase principal consiste en UC1-xOx, en la que x varia entre 0 y 0,8, segun la razon inicial UO2/UC o UO2/UC2- Se ha observado asimismo que el parametro de la red del UC1-xOx ligeramente afectado por el tratamiento termico, por ejemplo, en un 0,2%, aproximadamente, para x = 0,7, lo que muestra que la composicion del UC1-xOx no es estequiometrica. El calor de formacion del UC1-xOx se ha medido por el metodo de analisis termico diferencial, utilizando la reaccion: UC1-xOx + O2 U3O8 + CO2. Asimismo, se han calculado, basandose en las energias libres de formacion de varios compuestos presentes en el sistema, las condiciones de existencia del UC1-xNx como compuesto estable. Los resultados muestran que el UC1-xNx, cuyo x es inferior a un valor x' que depende exclusivamente de la presion del N2y la temperatura, se disocia formando UC1-x'Ox' y carbono o UC2, segun la presion y la temperatura. El que el ultimo componente sea C o UC2 depende tambien de la presion del N2 y de la temperatura. Se han realizado experimentos sobre la reaccion entre el U2N3 y el C, la reaccion entre el UC2 y el N2, e.t.c., en diferentes condiciones de presion y temperatura. Los resultados experimentales obtenidos concuerdan satisfactoriamente con los valores termodinamicos calculados. (author)Abstract (Russian)
Na osnovanii termodinamicheskikh issledovanij mozhno bylo predpolozhit', chto soedinenie UC1-xOx, esli ono sushchestvuet, dolzhno by bylo nakhodit'sya v ravnovesnom sostoyanii s gazom CO pri davlenii 10-4 mm rt.st. i pri temperature 1600 deg. C. Kompaktnye smesi UO2 s UC ili s UC2 v raznykh propordiyakh podvergalis' vozdejstvie temperatur v 1200 deg. C, 1600 deg. C i 1750 deg. C v vakuume pri 10-4 mm rtutnogo stolSa. Bylo obnaruzheno, chto posle okonchaniya reaktsii glavnaya faza sostoit iz UC1-xOx gde, v zavisimosti ot pervonachal'nogo sootnosheniya U02/UC ili UO2/UC2, velichina kh izmenyalas' v predelakh ot 0 do 0,8. Bylo obnaruzheno, chto parametr reshetki UC1-xOx izmenyalsya pod dejstviem termicheskoj obrabotki lish' na maluyu velichinu, naprimer na 0,2% pri x = 0,7, chto svidetel'stvuet o tom, chto v sostave UC1-xOx proiskhodit otklonenie ot stekhiometricheskogo sostoyaniya. Teplota obrazovaniya UC1-xOx izmeryalas' po metodu DTA, iskhodya iz reaktsii: UC1-xOx + O2 → U3O8 + CO2. Usloviya sushchestvovaniya v ustojchivom sostoyanii UC1-xNx byli vyschitany takte, iskhodya iz svobodnoj ehnergii obrazovaniya razlichnykh uchastvuyushchikh v reaktsii slozhnykh soedinenij. Rezul'taty pokazali, chto pri znachenii x men'shem, chem opredelennaya velichina x, obuslovlennaya isklyuchitel'no davleniem N2 i temperaturoj, UC1-xNx raspadaetsya pod dejstviem davleniya i temperatury na UC1-xNx i uglerod ili UC2. Vopros o tom, sostoit li vtoroj chlen iz C ili UC2, takzhe zavisit ot davleniya N2 i ot temperatury. Ehksperimenty po reaktsiyam mekhdu U2N3 i UC, a takzhe mezhdu UC2 i N2 i t.p. provodilis' v razlichnykh usloviyakh davleniya i temperatury. Byla ustanovlena khoroshaya soglasovannost' mezhdu ehksperimental'nymi rezul'tatami i termodinamicheskimi raschetami. (author)Additional details
Additional titles
- Original title (English)
- Formation de UC
Publishing Information
- Publisher
- IAEA
- Imprint Place
- Vienna (International Atomic Energy Agency (IAEA))
- Imprint Title
- New Nuclear Materials Including Non Metallic Fuel Elements. Vol. I. Proceedings of the Conference on New Nuclear Materials Technology, Including Non Metallic Fuel Elements
- Imprint Pagination
- 582 p.
- Series
- Proceedings Series
- Journal Page Range
- p. 429-444
- ISSN
- 0074-1884
Conference
- Title
- Conference on New Nuclear Materials Technology, Including Non Metallic Fuel Elements
- Dates
- 1-5 Jul 1963
- Place
- Prague (Czech Republic)
INIS
- Country of Publication
- International Atomic Energy Agency (IAEA)
- Country of Input or Organization
- International Atomic Energy Agency (IAEA)
- INIS RN
- 44067316
- Subject category
- S37: INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; S36: MATERIALS SCIENCE;
- Resource subtype / Literary indicator
- Conference
- Descriptors DEI
- CARBON; CARBON DIOXIDE; CARBON MONOXIDE; COMPACTING; DIFFERENTIAL THERMAL ANALYSIS; FREE ENERGY; HEAT TREATMENTS; LATTICE PARAMETERS; STOICHIOMETRY; THERMODYNAMICS; URANIUM CARBIDES; URANIUM DIOXIDE; URANIUM NITRIDES; URANIUM OXIDES U3O8
- Descriptors DEC
- ACTINIDE COMPOUNDS; CARBIDES; CARBON COMPOUNDS; CARBON OXIDES; CHALCOGENIDES; ELEMENTS; ENERGY; FABRICATION; NITRIDES; NITROGEN COMPOUNDS; NONMETALS; OXIDES; OXYGEN COMPOUNDS; PHYSICAL PROPERTIES; PNICTIDES; THERMAL ANALYSIS; THERMODYNAMIC PROPERTIES; URANIUM COMPOUNDS; URANIUM OXIDES
Optional Information
- Notes
- Figs., 7 tabs., 9 refs. Imprint:In two volumes
- Secondary number(s)
- STI/PUB--77(v.1)