Actual interpretation of the enhancement of Cu/Zn cementation kinetics by a "cement critical specific mass" is reconsidered. Working with a rotating disk electrode and varying the initial concentration of copper and. zinc ions over a large range, we show that copper deposit is not responsible for the kinetic transition. First, cement peeling off does not change the delay for the appearance of the second stage and the amplitude of the kinetic transition is a function of the initial concentration of zinc ions. Furthermore, the first stage duration decreases, and even this stage may disappear, on a substrate precorroded in the same solution replacing copper ions by Ce(IV) ions. On the other hand, the stage duration increases if a constant polarization is imposed to the substrate. Operating conditions at the Zn2+/Zn interface appear to be the essential parameter. Discussion includes morphological examinations.