Evaluation of the Anti-Corrosion Performance of Epoxy Composite Modified by LDH/O-MWCNT Hybrid Nanoparticles

In this study, a synthesize hybrid nanocarrier by co-precipitation method consisting of double-layer hydroxide (LDH) and multi-walled carbon nanotubes (MWCNT) was used as a nanocarrier containing corrosion inhibitor in order to enhance the corrosion protection performance of applied epoxy coating on St12 substrate in 3.5 wt.% NaCl environment. Also, by adding sodium triphosphate (TSP) nanoparticles as a corrosion inhibitor to the synthesized hybrid nanoparticles, a smart anti-corrosion coating was made, which confirmed the correctness of the synthesis of MgAl-LDH/OMWCNT hybrid nanoparticles and the correction of loading of the TSP inhibitor molecule in the MgAL-LDH /OMWCNT structure by characterization tests such as XRD, Raman and FTIR and the corrosion inhibition mechanism was carried out using EIS, polarization and FE-SEM/EDS analyses. The polarization results showed the 20% reduction of corrosion current density. In the following, the anti-corrosion properties of the epoxy composite coating were investigated by EIS analysis. The results showed the active inhibition of the TSP-LDH/OMWCNT/EP coating in the scratch areas, in the other word an enhancement of Rct, from 65.97 k.cm2 for pure EP sample to 94.87 k.cm2 for TSP-LDH/OMWCNT/EP indicated the reflection of improvement self-healing behavior of the system. Moreover, the results of pull-off adhesion and cathodic delamination tests demonstrated the durability of the anti-corrosion properties of the coated samples with LDH/OMWCNT and TSP-LDH/OMWCNT nanoparticles due to better compatibility with the epoxy, which led to a decrease in adhesion loss and a 36% decline in the diameter of cathodic delamination to 36% and so it indicated the improvement in the corrosion resistance of epoxy coating.