Multi-physical and anti-corrosion properties of graphene-reinforced epoxy nanocomposite coatings for industrial applications
Md. Ramjan Ali, Mohammad Asaduzzaman Chowdhury, Mohammad Shahin, Md. Mostafizur Rahman, Md Osman Ali, M. A. Gafur
Abstract
Polymer-based coatings are widely used as a protective barrier to corrosion, but their performance is not sufficiently sustainable for industrial applications due to the formation of micropores and microcracks during solidification. Graphene is a promising reinforcing element acting as a filler for polymeric coatings. This study used 1-5 wt.% graphene synthesized by the electrochemical exfoliation process as a reinforcing nanofiller to manufacture graphene-reinforced epoxy nanocomposite (GREN) coatings. Copper was used as a substrate material for coating with GREN by a bar coating method. GREN coatings were characterized by X-ray diffraction, Raman spectroscopy, FTIR spectroscopy, FESEM, and EDX. A comprehensive investigation was conducted on the various multi-physical properties of GREN coatings, including coating thickness, surface roughness, adhesiveness, surface wettability, water absorptivity, thermal stability, electrical conductivity, and anti-corrosion capabilities. The results exhibited that graphene fills micro-pores produced in epoxy during solidification. The surface roughness significantly decreased to 0.25 µm with the addition of 5 wt.% graphene in pure epoxy. In addition, the adhesiveness, thermal stability, and electrical conductivity of GREN coatings increased with the increase in graphene content. The GREN coatings containing 3 wt.% and 5 wt.% graphene revealed hydrophobic surface showing 94° and 102° water contact angle, respectively. In the electrochemical analysis and immersion test in 3.5% NaCl solution for 600 h, the GREN coatings showed higher corrosion resistance without compromising their electrical conductivity compared to the pure epoxy. Based on the results, GREN can be a promising coating material for aerospace, mining, and electronic packaging applications. Apart from this, the results of this work will explore the new significance in industry, where multi-physical properties from a single nanocomposite coating are crucial.