| Abstract: | The objective of this work has been to combine the sol-gel method and the electrophoretic deposition (EPD) process to prepare thick coatings onto metallic substrates. Two different routes were used for preparing the sol-gel silica suspensions. On one hand, silica particulate sols were obtained by basic catalysis of alkoxides and alkylalkoxides. On the other, silica suspensions were prepared by adding a commercial colloidal silica sol to an organic-inorganic acid catalysed silica sol. The properties of the suspension and the physical parameters associated to EPD (current density, potential, electric field and deposition time) were studied. Crack-free deposits up to 20  m were obtained after drying and crack-free glass-like coatings of 12 m after sintering at 500°C for 30 minutes. The electrochemical behaviour of these coatings was evaluated by potentiodynamic methods, showing an excellent behaviour against corrosion. |
