T. Arima et al., The oxidation kinetics and the structure of the oxide film on Zircaloy before and after the kinetic transition, J NUCL MAT, 294(1-2), 2001, pp. 148-153
Oxidation kinetics of Zircaloy-4 have been measured using a micro-balance t
echnique in CO-CO2 gas mixtures between 450 degreesC and 600 degreesC. Oxid
ation kinetics of Zircaloy-4 obeyed a cubic rate law with time at 450-600 d
egreesC up to 24 h. At 600 degreesC, the kinetic transition occurred after
about 36 h. After the transition, oxidation kinetics obeyed a linear rate l
aw. X-ray diffraction patterns for the samples oxidized at 600 degreesC sho
wed that the volume fraction of tetragonal phase of zirconia decreased with
time until the kinetic transition occurred and was almost constant after t
hat. In addition, stresses in the oxide films were found to be larger for t
he pre-transition samples than for the post-transition ones. (C) 2001 Elsev
ier Science B.V. All rights reserved.