INTEMA   05428
INSTITUTO DE INVESTIGACIONES EN CIENCIA Y TECNOLOGIA DE MATERIALES
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Hybrid sol gel coatings containing nanoclays for corrosion protection of mild steel
Autor/es:
IANINA SANTANA; A. PEPE,; SERGIO PELLICE; SILVIA CERE
Lugar:
Troia
Reunión:
Simposio; 11th International Symposium on Electrochemical Methods in Corrosion Research, EMCR 2015; 2015
Institución organizadora:
Sociedad Internacional de Electroquimica
Resumen:
Sincethe adoption of new regulations towards protection of the environment, the useof chromate based coatings is highly limited. So, the development of newenvironment-friendly high performance anticorrosive coatings is a significanttopic for the scientific researchers. In this context, coatings containinglanthanides elements like Ce and La are considered since they potentially canprovide a good anticorrosive protection by means of a self-healing mechanism.Sol-gel coatings are compatible with a variety of substrates and can be appliedas very thin films having high physicochemical and thermal stability and beingpossible to be functionalized with a large variety of additives. The barrierproperties of sol-gel coatings can be substantially improved by controlling thecrosslinking density of its structure or by incorporation of nanoparticlesthat, in turn, can work as mechanical reinforcement. However, the structuralmodification introduced by lanthanide compounds on the silica network leaves anopen path to the water diffusion through the coating. In the last years, thedevelopment of new nanocomposites was highly explored by the use of nano-clays dueto its high availability and economical convenience. Those nanoparticles arehighly employed as rheological modifiers in the industry of cosmetic and paintsand, at the same time, their use as load for composite materials can improveboth the mechanical and barrier properties. However, the use of nanoclays inthe field of sol-gel coatings is an area that has not been extendedly analysed.Inthis work nanostructured hybrid films were synthesized by the sol?gel routefrom tetraethoxysilane (TEOS) and 3-glicidoxipropyl-trimetoxisilano (GPTMS)  using laminar nanoclays (Laponite Na0,7[Si8Mg5.5Li0.3H4O24]-0,7)toimprove mechanical and barrier properties, and Ce(NO3)36H2Oas a supplier of Ce(III) to provide an inhibitingeffect in the event of coating failure. Carbon steel plates, AISI 1010, wereused as substrates. Prior to the application of the coating, samples weretreated with a phosphoric acid 2 % v/v in order to improve coating adherence.Inorder to evaluate cerium effect, electrochemical behaviour of films containingLaponite and cerium salts (TGLaC) were compared with films containing onlyLaponite (TGLa) by means of potentiodynamic polarization tests andelectrochemical impedance spectroscopy (EIS) measurements using a 0.35 wt% NaClsolution. Microstructural characterization, surface analysis of substrates andsol-gel coatings were performed by optical microscopy and by XPS techniques.