Hybrid sol-gel coatings doped with cerium to protect magnesium alloys from corrosion

Noé Verner Murillo Gutierrez (1) , Florence Ansart (1) , Jean-Pierre Bonino (1) , Marie Joelle Menu (1) , Marie Gressler

1 CIRIMAT - Centre interuniversitaire de recherche et d'ingenierie des matériaux

Hybrid coatings produced via the sol-gel route were deposited onto an Elektron 21 magnesium alloy. The sol consisted of tetraethyl-orthosilicate (TEOS) and 3-(trimethoxysilyl)propylmethacrylate (MAP) to which corrosion inhibitors were added. The influence of the cerium concentration on the anti-corrosion properties of the hybrid coating is presented. Furthermore, the morphology of the organic/inorganic coatings deposited on the magnesium alloy was determined with scanning electron microscopy (SEM). In parallel, the electrochemical behavior during the immersion in a 0.05 M NaCl corrosive solution was studied with electrochemical impedance spectroscopy (EIS). It was proven that the hybrid films exhibit a high impedance modulus during the first hours of the immersion and that an addition of cerium to the sol with a concentration of 0.01 M considerably increases the durability of the film, delaying its degradation during the immersion. In addition, this project especially focusses on determining the critical concentration of the cerium salt at which the impedance modulus of the hybrid coating strongly decreases during the immersion.

Mots clés: Nanos; Magnezij; Sol-gel; Inhibitor korozije; EIS

Domaines: Matériaux

Noé Verner Murillo Gutierrez, Florence Ansart, Jean-Pierre Bonino, Marie Joelle Menu, Marie Gressler. Hybrid sol-gel coatings doped with cerium to protect magnesium alloys from corrosion. Materials and Technology, 2015, 49 (3), pp.453-456. ⟨10.17222/mit.2014.077⟩. ⟨hal-02433707⟩