Portugaliae Electrochimica Acta 2009, 27(3), 257-267 DOI: 10.4152/pea.200903257 PORTUGALIAE ELECTROCHIMICA ACTA ISSN 1647-1571 Synthesis by Sol-gel Route and Characterization of Ceria Doped Silica Coatings on Commercial Carbon Steel M.A. Domínguez-Crespo, 1,* E. Ramírez-Meneses, 1 A.M. Torres-Huerta, 1 A. García-Murillo, 1 E.M. Arce-Estrada, 2 O.G. Castillo-Hernández 3 1 Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada (CICATA-IPN) Km. 14.5 Carr. Tampico-Puerto Industrial, C.P. 89600, Altamira, Tamaulipas, México 2 Instituto Politécnico Nacional, Departamento de Metalurgia y Materiales. A.P. 75-874, 07300 México, D.F. México 3 Estudiante del Programa de Posgrado en Tecnología Avanzada, Unidad Altamira del IPN México Received 25 April 2008; accepted 14 January 2009 Abstract The use of silane formulations for the pre-treatment of metallic substrates prior to painting or as topcoat has been increasing during the recent years. The proposed formulations are very attractive because they present environmental friendliness, enhance adhesion properties and provide a barrier layer that delays the corrosion processes. One of the most used techniques to synthesized based-SiO 2 coatings is sol- gel. The preparation of sol-gel coatings with specific chemical functions offers potential advantages over traditional methods as it offers tailoring of their structure, texture and thickness and allows the fabrication of large coatings. The present work investigates the electrochemical behaviour of commercial carbon steel coated with ceria doped SiO 2 by sol-gel process in basic media. To evaluate the influence of temperature on adhesion and protective properties, the coatings were sintered at three different temperatures, 623 K, 723 K and 873 K, for 3 h. The anticorrosion behaviour, of the films has been characterized in an aggressive medium by electrochemical techniques, while structural characteristics and morphology was followed by X-Ray Diffraction, Fourier Transformed Infra-Red and Scanning Electron Microscopy techniques. The results indicated that the thin films act as a protective barrier against exposure to the corrosive medium (3.5 wt-% NaCl solution) and increase the lifetime of the susbtrate. Keywords: sol-gel process, SiO 2 coatings, structural characterization, rare earths, corrosion prevention. * Corresponding author. E-mail address: mdominguezc@ipn.mx