Use this URL to cite or link to this record in EThOS: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.467707
Title: A study of the kinetics of oxidation of uranium-aluminium compounds
Author: Openshaw, Peter Raymond
ISNI:       0000 0001 3459 4300
Awarding Body: University of Surrey
Current Institution: University of Surrey
Date of Award: 1962
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Abstract:
The kinetics of the high temperature oxidation (250 - 600 C), in purified oxygen, of the intermetallic compounds UAl2, UAl3 and UAl4 have been studied using a microbalance and a thermal balance. The compound UAl42 was prepared by an arc melting process, whilst samples of UAl3 were supplied by the Metallurgy Division, Harwell. UAl4 could not be obtained in a pure form and its behaviour was indirectly assessed by 'extrapolating' the behaviour of uranium-aluminium alloys containing various proportions of UAl4 to that of the pure compound. Alloys containing large amounts of UAl4 oxidised linearly over the range 350-550 C, except for the initial stages of film formation. At 600 C a cubic rate of oxidation was observed which gave much smaller weight gains than at lower temperatures. It is suggested that this phenomenon is due to sintering of the oxide film. Alloys containing small proportions of UAl4 oxidised in a logarithmic manner over short periods and in a slow linear manner thereafter. Sintering and preoxidation experiments were also conducted with the oxide films on UAl4 alloys. UAl2 and UAl3 oxidised linearly after a short initial period of either increasing or decreasing oxidation rate. The oxide films produced have been examined chiefly by X-ray powder microscopy and electron microscopy. The only oxide identified was U3O8. The films have few surface features until after prolonged oxidation, when in the case of UAl4 and UAl3, cracking occurs. A unique system of concentric crack formation occurs in the oxide films formed on UAl4 alloys at 500 C, whilst only random cracking occurs at 600 C. All the linear rates of oxidation are attributed to either the formation of a porous film and a thin coherent barrier film, or to a porous film and a rate determining reaction. These possibilities are fully discussed.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.467707  DOI: Not available
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