In the present work, mechanical features are investigated in the case of ZrO 2 thermal oxide films growing on a Zr alloy at the temperature of 550°C. The effects of a nanocrystallisation treatment on high temperature oxidation of a zirconium alloy are specifically studied. High temperature oxidation is performed in order to show benefits of such a nanocrystallisation on corrosion resistance and its influence on the mechanical fields. Experimental results obtained by Raman spectroscopy give the growth stress evolution in ZrO 2 films. Using a modelling of the system, both asymptotic forms and an optimization procedure are developed to determine the mechanical characteristic parameters of the system.