Thermodynamics of Vaporization of ZrI4 from Substoichiometric Solid Zirconium Iodides

Cubicciotti, Daniel; Lau, K. H.

doi:10.1149/1.2129136

Cited by 12 publications

(6 citation statements)

References 8 publications

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“…To apply this model to the present system requires an evaluation of the equilibrium partial pressures of the gaseous species. The thermodynamic information required (13)(14)(15)(16) to evaluate the partial pressures in equilibrium with zirconium metal are available (9). The calculation shows that the predominant species is monatomic iodine.…”

Section: Fig 3 Adsorption Isotherms For Iodine On Zirconiummentioning

confidence: 99%

Auger Electron Spectroscopy Study of the Chemisorption of Iodine on Zirconium

Krishnan

Wood

Cubicciotti

1980

J. Electrochem. Soc.

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Auger electron spectroscopy was used to observe the relative coverage of iodine on the surface of a zirconium crystal exposed to a flux of iodine gas molecules. The zirconium was heated to temperatures of 1000–1300 K, and the iodine pressures corresponded to 10−4–10−6 Pa (10−9–10−11 atm). Iodine was found to chemisorb on the surface; the isotherms corresponded to the Temkin model. Isoteres derived from these isotherms showed a logarithmic dependence of pressure on reciprocal temperature. The slopes of the isoteres indicated an enthalpy of formation of the surface layer of about 60 kcal/mole. The thermodynamics of formation of an iodine adspecies on a zirconium surface were compared with the thermodynamics of formation of zirconium monoiodide, the lowest solid iodide of zirconium.

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Section: Fig 3 Adsorption Isotherms For Iodine On Zirconiummentioning

confidence: 99%

Auger Electron Spectroscopy Study of the Chemisorption of Iodine on Zirconium

Krishnan

Wood

Cubicciotti

1980

J. Electrochem. Soc.

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“…That is, in general the major vapor species in gaseous ZrI4 so that reaction [18] represents the equilibrium vaporization process. Nevertheless, reaction [2] can be considered per se. The values are in keeping with the relative pressures of species calculated for the equilibrium with zirconium at temperatures below about 1200 K in Ref.…”

Section: N [17]mentioning

confidence: 99%

“…ZrI4-~(s) ZrI4-x-y(s) + Zrl~(g) [1] Zirconium tetraiodide is the predominant gaseous metal iodide species in equilibrium with any condensed phase in the zirconium-iodine system below about 1000 K (2). The equilibri,m behavior of the condensed phases must conform to the phase rule.…”

mentioning

confidence: 99%

“…For this phase to be in equilibrium with triiodide, it must ex- Zrf~-~-Zrl~, -tend to ZrI4-~, since stoichiometric ZrI4(s) vaporizes congruently (1). The ZrI solid solution composition limits were established by x-ray and chemical analysis of equilibrated samples (4), whereas those of the ZrI2 and Zrl phases were established by observation of oneand two-solid-phase vaporization behavior (2,3,5). Two-solid-phase behavior was observed (3) between ZrI1.05 and Zr.…”

mentioning

confidence: 99%

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Estimated Thermodynamic Properties of the Solid Zirconium Iodides

Lamoreaux

Cubicciotti

1981

J. Electrochem. Soc.

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Literature values of ZrI4 pressures in equilibrium with solids of the zirconium‐iodine system have been used to calculate Zr and ZrI4 activities as functions of composition at 700 K. These activities, along with estimated heat capacities and free energy functions, were used to derive values of the activity of iodine and of the enthalpies of formation of solid stoichiometric normalZrI , ZrI2 , and ZrI3 . The estimated enthalpies of formation were: normalΔH2980false(normalZrI,normalsfalse)=−34.0±2.5 normalkcal/normalmole ; normalΔH2980false(ZrI2,normalsfalse)=−66.4±2.5 normalkcal/normalmole ; normalΔH2980false(ZrI3,normalsfalse)=−93.6±3.5 normalkcal/normalmole .

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“…The thermochemical aspect of this problem has been studied in detail by D. Cubicciotti and co-workers [4][5][6] and progress in this area is reported in several publications. Taking the thermodynamic data into consideration, Gotzman [13] proposed that the critical iodine partial pressure, deduced by Hofmann et.…”

Section: Introductionmentioning

confidence: 99%

Kinetic study of reaction between zirconium and iodine

Yang

Tsai

1989

Journal of the Chinese Institute of Engineers

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Stress corrosion cracking (SCC) of zircaloy cladding is generally believed to be the major failure mode of current nuclear fuel in light water reactors. Iodine, an abundant fission product, has been identified to possibly cause zircaloy to become susceptible to SCC. An understanding of the kinetics of the reaction between zirconium and iodine is an essential part of the complex iodine induced SCC mechanism. The kinetics of reaction between zirconium and iodine are investigated by TGS-2 thermogravimetry system at the temperature range of 300~350°C. Results show that the activation energy, pre-exponential factor and reaction order of molecular iodine are 43.8 kJ/mole, 3.1 mg/cm 2 -min and 1.06, respectively. A study of the effect of surface texture on the kinetics is also performed by using the different cold rolled specimens whose textures are examined by an X-ray diffraction method. Cold rolling will shift the basal pole to the rolling direction and only influence slightly the pre-exponential factor. The results on zircaloy-4 also indicate that it exhibits better corrosion resistance in the iodine vapor as compared to zirconium. m m w o xmftmm TGS-2 mmm^^mmmmits.m^m±m (&$%m) m fe'ffeRSI^^ Sffiifii^^»JH 43.8 kJ/mole, 3.1 mg/cm 2 /min R 1.06 °j DX#ffifSg^E±«t«S4»^b • ft * [ 0001 ] £«lfiil«tl!3l5fiitft«ffi Downloaded by [Cornell University Library] at 04:

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Thermodynamics of Vaporization of ZrI4 from Substoichiometric Solid Zirconium Iodides

Cited by 12 publications

References 8 publications

Auger Electron Spectroscopy Study of the Chemisorption of Iodine on Zirconium

Auger Electron Spectroscopy Study of the Chemisorption of Iodine on Zirconium

Estimated Thermodynamic Properties of the Solid Zirconium Iodides

Kinetic study of reaction between zirconium and iodine

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