Current-potential curves for zirconium in fluorinated nitric medium were obtained using a rotating disc electrode. The curves exhibited four different domains according to the potential, and suggested a seven-step reaction model composed of three competing paths. Quantitatively verified by comparing computed and experimental curves, this model accounts for the behaviour of either zirconium or its main industrial alloy, Zircaloy 4, over potentials ranging from the corrosion potential up to the zirconia passivation potential. Moreover, the model allows the rate of elementary steps to be determined, as well as the coverage ratio of the intermediate species considered. These results correlated with scanning electron microscopy observations and proved to be particularly sensitive to slight modifications of the electrochemical system. The model can also be considered as a promising tool in the study of zirconium alloy pickling in acidic media and for optimising the resulting surface quality.