Enhancing the corrosion resistance of waterborne inorganic zinc-rich coatings by parallel aligning magnetized reduced graphene oxide

Abstract

Zinc-rich coatings (ZRCs) are widely used as primers to protect steel. However, their corrosion resistance is limited. Although the addition of graphene oxide (GO) can enhance anticorrosion efficiency, GO tends to agglomerate in ZRCs and spreads in a disordered manner because of its high surface energy. This weakens the ability of GO to prevent the invasion of corrosive media into substrates. In this study, magnetized reduced GO (rGO) was synthesized using rGO with nanoscale iron powder. The magnetized rGO powder was then incorporated into waterborne inorganic ZRCs and placed in a uniform magnetic field. The magnetized rGO powder within the coatings aligned parallel to the substrate instead of exhibiting disordered distribution. This behavior clearly increased the barrier and cathodic protection abilities of the coatings. Results indicate that when 0.1 wt% magnetized rGO was added, the compactness of the coatings was substantially enhanced and the cathodic protection time at inscribed areas increased to 192 h. By contrast, the cathodic protection time of the magnetized rGO free ZRCs was only 96 h. The excellent corrosion assistance of the magnetized rGO incorporated waterborne inorganic ZRCs was attributed to the good barrier protection effect and electron transmission of the aligned magnetized rGO in the coatings.

Keywords

• Magnetized rGO
• Zinc-rich coatings
• Parallel aligning
• Corrosion resistance
• Cathodic protection
• Barrier protection