8-Hydroxyquinoline/nanoclay epoxy nanocomposite as a smart coating for early corrosion detection
H. Eivaz Mohammadloo, Ali Asghar Sarabi, Sh. Roshan, A. Eivaz Mohammadloo
Abstract
The effect of different concentrations of nanoclay incorporated in the epoxy coating containing 8-hydroxyquinoline (8-HQ) on early corrosion detection, electrochemical and optical properties of the applied coating was investigated. The 8-HQ and nanoclay composite samples were characterised by UV–Vis spectroscopy, FE-SEM, EDS, XRD, EIS, fluorescence spectroscopy and microscopy. Then, the optimised coating containing 8-HQ and nanoclay was applied on the Ti–Ni conversion coated steel for further analysis. Adhesion measurements indicated that the adhesion strength of the 8-HQ + Nano + TiNiCC was 4.6 ± 0.45 MPa with dominant cohesion failure. Based on the EIS measurement, the polarisation resistance of Ti–Ni modified steel coated with 0.1 wt-% 8-HQ and 2 wt-% nanoclay composite was about 1.5 × 1010 ohm.cm2 even after 4 weeks immersion in 3.5 wt-% NaCl solution. During the same period as a result of fluorescence microscopic study, the fluorescent spot appeared as a result of Fe2+/Fe3+ ions production at anodic regions.