The production of a multi-walled carbon nanotube/hexamethylene diisocyanate nanocomposite coating on copper by electrophoretic deposition

A multi-walled carbon nanotube (MWCNT)/hexamethylene diisocyanate (HDI) composite coating with excellent microstructural homogeneity was produced on copper substrate from aqueous suspensions using electrophoretic deposition (EPD). The concentrations of different additives were optimized to obtain stable suspensions of MWCNT. At the optimum EPD condition, a coating of thickness 170 μm was obtained at voltage of 30 V and deposition time of 3 min with well dispersed MWCNT in the polymer matrix. The deposit yield increased linearly with deposition time. The adhesive strength of the MWCNT/HDI composite coating was assessed qualitatively by peel test. The composite coated specimen showed greater resistance to corrosion in the chloride containing environment with inhibiting efficiency 96.65%. The mechanism for adhered coating is due to better wetting of HDI on copper substrate followed by acid-base reaction between metal hydroxide and polymeric resin. The potential application of the nanocomposite coatings could be protecting copper based metallic structure in marine environment.

► The dosages of additives are optimized to obtain stable suspensions of MWCNT. ► The surface charge measurement data are very useful to select proper EPD conditions. ► A coating of smooth and uniform thickness 170 μm is achieved at optimum condition. ► Raman spectroscopic analysis revealed strong interaction between HDI and MWCNT. ► Nanocomposite have greater resistance to corrosion with inhibition efficiency 96.65%.