In-situ AFM and EIS study of a solventborne alkyd coating with nanoclay for corrosion protection of carbon steel
Li, Jing; Ecco, Luiz; Fedel, Michele; Erminic, Valentina; Delmas, Gregory; Pan, Jinshan
A solventborne alkyd composite coating containing modified montmorillonite (MMT) nanoclay was made on carbon steel, and its corrosion protection was investigated by in-situ atomic force microscopy (AFM) and electrochemical impedance spectroscopy (EIS) measurements in 3 wt.% NaCl solution. X-ray diffraction (XRD) analysis indicated intercalation of the MMT sheets in the composite coating. Thermogravimetric analysis (TGA) demonstrated improved thermal stability of the composite coating due to the modified nanoclay. Scanning electron microscopy (SEM) and AFM examination revealed dispersion and also some aggregation of the nanoclay particles in the coating. In-situ AFM images show a stable coating surface at nano-scale during relative long time exposure in the NaCl solution, indicating an enhanced stability of the composite coating. The EIS results confirmed that the composite coating provides an enhanced barrier type corrosion protection for carbon steel in the corrosive solution, which could be attributed to the intercalated lamellar MMT sheets in the coating that block the defects and decrease the transport of water and corrosive species. (C) 2015 Elsevier B.V. All rights reserved.
Alkyd coating; Nanoclay; Corrosion protection; In-situ AFM; EIS
Progress in Organic Coatings
2015, Volume: 87, pages: 179-188
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