Indian Journal of Advances in Chemical Science Volume: 5, Issue 4: , September 2017


ISSN No.: 2320-0898 (Print); 2320-0928 (Electronic)

DOI:  10.22607/IJACS.2017.504005



Research Article


      Oxidation Kinetics of Zr-Nb Alloys in Dry Air in the Temperature Range             723-790 K    
S. P. Roy*, N. K. Gupta, S. K. Mukerjee, S. C. Parida

The reaction kinetics of three different Zr–Nb alloys with Zr-0.7 wt% Nb, Zr-2.5 wt% Nb, and Zr-5 wt% Nb were investigated using the thermogravimetric technique in the temperature range of 723-790 K. Analysis of the oxidation curves revealed that, at all oxidation temperatures, the reaction follows initially parabolic and then linear oxidation reaction mechanism. The X-ray powder diffraction pattern of the oxidation products revealed the formation of ZrO0.27 and Nb0.20Zr0.80O2.10 at each temperature. The rate constants were evaluated using rate equation and the activation energy by Arrhenius equation in both the parabolic and linear regions of each alloy. The activation energies of Zr-0.7 wt% Nb, Zr-2.5 wt% Nb, and Zr-5 wt% Nb alloys in the parabolic region are 225, 222, and 198 kJ/mol, respectively, whereas in the linear region, the activation energies of the corresponding alloys are 156, 136, and 123 kJ/mol.


Key words:  Zr–Nb alloys, Oxidation behavior, Activation energy, Thermogravimetric technique



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