It is important to protect steel infrastructure, such as pipelines, from environmental corrosion. The primary method for this protection is by utilizing coatings, especially epoxy (EP) coatings. In recent years graphene has shown a great deal of promise as a candidate for barrier applications, including anti-corrosion coatings. For example, reduced graphene oxide laminate films produced by the chemical reduction of graphene oxide are found to provide excellent barriers to strong chemicals and salt solutions. A family of new graphenic materials is being developed from the top-down exfoliation of natural graphite, including graphite nanoplatelets (GNP), more exfoliated graphene materials (MEG), and graphene oxide (GO). These materials vary in their properties, with lateral dimensions, the degree of exfoliation, oxygen content, and cost being among the most significant differences, and are suitable for processing with polymers into nanocomposite coatings. In this talk, we discuss the viability of processing these materials with EP for application as anti-corrosion coatings on steel substrates. The materials and composites are characterized physicochemically before and after processing. The anti-corrosion performance is evaluated by salt-fog and electrochemical corrosion testing. The graphenic materials chosen for these studies show desirable technical characteristics (e.g. homogeneity, high aspect ratios, etc.), and are low-cost and commercially available. For GNP / EP composites, we find an excellent resistance to 1 M HCl aqueous solution over several days, as well as a strong resistance to a standard salt-fog corrosion test environment. For both test environments, it is found that an improvement in anti-corrosion performance is seen with a clear trend towards higher GNP concentrations (above ~1%). The salt-fog corrosion testing further suggests that increasing the lateral dimensions of the GNP materials leads to better improvements in anti-corrosion performance. A comparison is made with similar published studies and it is determined that processing conditions can have a marked effect on the quality of the films and hence the anti-corrosion test results observed. Further testing of these trends is underway with an expanded concentration range, as well as with MEG and GO materials. These new results will be discussed in this talk.
Journal: TechConnect Briefs
Volume: 1, Advanced Materials: TechConnect Briefs 2018
Published: May 13, 2018
Pages: 240 - 243
Industry sector: Advanced Materials & Manufacturing
Topics: Coatings, Surfaces & Membranes