Cathodic electrosynthesis of cerium-containing films onto model Ni and both raw and aluminized nickel-based superalloy was investigated from concentrated aqueous solutions of cerium nitrate at room temperature. The correlations between the electrochemical features and the microstructure of the resulting layers were established. Polarization curves revealed that transient deposition stages were the most critical as both composition and surface condition of the substrate strongly influenced the nucleation and growth processes and the final morphology of the coatings. SEM/EDS analyses showed that the films initially developed in a homogeneous manner onto raw substrates whereas nuclei grew mainly onto grain boundaries of aluminized samples before covering the grains. Quick growth kinetics led to oxygen defective deposits composed of a mixture of hydrated cerium oxide/hydroxide incorporating carbonates and trapped nitrates due to incomplete reactions. (C) 2012 Elsevier Ltd. All rights reserved.