Superior to graphene: super-anticorrosive natural mica nanosheets

Graphene has been generally considered to be the most ideal anticorrosive material based on its extraordinary impermeability, but tends in practical applications to promote metal corrosion because of its inherently high electrical conductivity. Mica nanosheets (MNSs), in contrast, display excellent electrical insulation properties, as well as excellent temperature stability and chemical durability, and show tremendous potential for protecting metals, and hence are a promising substitute for graphene. To date, however, there have been no reports about MNS-based anticorrosive coatings, since it is much more difficult to exfoliate high-quality MNSs than other layered materials. In this work, high-concentration (4.3 mg ml-1) ultrathin MNS (1-5 layers) dispersions were synthesized based on a facile and efficient hydrothermal exfoliation approach. Epoxy (EP) coatings were filled with the as-obtained MNSs to enhance the anticorrosion performance of the coatings, and their corrosion behaviors were studied systemically through a series of measurements. With the addition of only 0.4 wt% MNSs, the corrosion rate was observed to be reduced 6500 fold, and the coating impedance increased by four orders of magnitude compared with the blank EP coating. We believe that this method opens a novel avenue for developing high-performance anticorrosive coatings to replace graphene materials for metal protection.