Comparative corrosion resistance of graphene sheets with different structures in waterborne epoxy coatings

Although substantial statements report the capability of graphene for corrosion prevention, its further application is limited by the non-comprehension of its structural variation in different coatings. Herein, graphene sheets with four structures were incorporated waterborne epoxy to fabricate different types of composite coatings (named EP-G(a), EP-G(b), EP-GO and EP-GS, respectively) as well as the pure waterborne epoxy coating was fabricated for comparison. The corrosion behaviors of as-fabricated coatings with and without graphene sheets were systematically characterized via potential, impedance testing and Tafel curves by immersing in 3.5 wt % NaCl solution. It was remarkable to point out that EP-G(a) composite coating could possess a promising long-term corrosion protection capability. The corrosion protection mechanism of graphene-based composite coatings were verified as the barrier effect of impermeable graphene sheets that confirmed by the analysis of corrosion products. Moreover, the scanning vibrating electrode technique in-depth revealed the relationship between the graphene structures and corrosion performances of the composite coatings. With the occurrence of commercialized application of graphene-based coatings, these works displayed a suitable approach toward the long-term corrosion behavior, which was able to be extended to other two-dimensional materials for anti-corrosion coatings.