Electrochemical deposition of Cu2O on stainless steel substrates:: Promotion and suppression of oriented crystallization

Cu(2)O coatings with 111 orientation comprising crystallites with a triangular pyramidal morphology could be deposited at pH = 12 from baths stabilized with a variety of ligating agents showing that oriented crystallization is independent of the ligand structure. When the deposition is carried out at very high [OH(-)] concentrations (pH > 14), the coatings are unoriented and comprise crystallites with octahedral morphology. In some of these coatings, the loss of orientation is attributed to the random tilt of the long axes of the crystallites with respect to the normal to the substrate. In others, the loss of orientation is due to the redissolution of pre-grown faceted crystallites. Given that the dominant morphology of the crystallites obtained under these conditions is octahedral, crystal growth takes place under conditions of thermodynamic control. (C) 2007 Elsevier Masson SAS. All rights reserved.