A cellular automaton model is used for 3D simulations of metal corrosion in electrolyte solutions in potentiostatic conditions. The focus of this research is the formation of the passive layer on the metal surface. A general, mesoscopic-scale model is used. It contains only the elements necessary to reproduce the most important features of passivation. It is a 3D version of the 2D model presented in our previous papers. The simulations are run on graphics processing units which allow an effective operation on large 3D lattices. We consider the influence of three factors: the rate of corrosion (related to the electric potential), solubility of the corrosion products and their adhesion or absence of adhesion to the metal surface. For each set of the parameters we wait in the simulation run for the system to attain the steady state. Then we collect data characterizing steady-state properties such as electric current density, passive layer thickness, its roughness and overall morphology. The qualitative properties of passivation are reproduced in our 3D simulations confirming the conclusions based on earlier, 2D simulations. (C) 2018 Elsevier Ltd. All rights reserved.