Corrosion protection of carbon steel by silica-based hybrid coatings containing cerium salts: Effect of silica nanoparticle content

IANINA, SANTANA; ANDRÉS, PEPE; SERGIO, PELLICE; SILVIA, CERÉ

SURFACE AND COATINGS TECHNOLOGY

ELSEVIER SCIENCE SA

Lugar: Amsterdam; Año: 2015

0257-8972

One strategy for minimising corrosive attack on carbon steel involves the application of hybrid coatings rich inrare earths, on the basis of their low toxicity and environmental sustainability. Tetraethoxysilane (TEOS) and3-glycidoxypropyl-trimethoxysilane (GPTMS) were each used here as precursors, together with various quantitiesof colloidal silica suspension, to improve barrier properties of the coatings. Ce(NO3)3·6H2O was added as a sourceof Ce(III) for further inhibition of corrosion. The corrosion resistance of each kind of sample was evaluated usingpotentiodynamic polarisation measurements and electrochemical impedance spectroscopy (EIS) in 0.35 wt.%NaCl solution. The electrochemical behaviour at various immersion times was modelled by equivalent circuitsto demonstrate the effect of silica nanoparticle loading on corrosion. Additional testing was performed underharsh conditions of salt spray chamber. The microstructure and composition of sol–gel coatings were characterisedby scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM/EDS), focused-ion beamSEM/EDS analysis, X-ray photoelectron spectroscopy and confocal microscopy.