Oxidation behavior of U-6 mass% Zr alloy
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The oxidation behavior of U-6 mass% Zr alloy was studied by using thermogravimetric technique. Oxidation reaction was carried out by heating alloy sample in a stream of oxygen. Both isothermal and non-isothermal methods were used to study the kinetics of oxidation reaction. Model-free isoconversional method was used to derive the kinetic parameters. A single-step oxidation reaction was observed. The completion of oxidation reaction was ascertained by constancy of sample mass with respect to time and temperature. It was observed that under the favorable conditions of temperature, time and concentration of oxygen (Vpm of O2) alloy sample underwent ignition also. Hence, dependence of inception of ignition reaction on concentration of oxygen (Vpm of O2) was also studied. The effective activation energy obtained using isoconversional method for U-6 mass% Zr alloy was found to be 85 ± 7 kJ mol−1 for ‘α’ = 0.1 to 0.8 (non-isothermal experiments). It was inferred that prolonged exposure of the alloy to oxygen at room temperature resulted in its surface oxidation. The products of oxidation reaction did not result in a protective coating on the specimen.
KeywordsUranium zirconium alloy Kinetics Oxidation Thermogravimetric analysis Isoconversional method
The authors wish to thank Dr. B. P. Reddy, Head, Pyrochemical & Materials Processing Division for providing U-6 mass% Zr alloy sample for this study.
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