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1. A coating system for coating a metallic substrate that is susceptible to corrosion, the coating system being for creation of a first coating on the metallic substrate, and, subsequently, a second coating over the first coating, the coating system comprising a first composition and a second composition, wherein the first coating is formed from the first composition and the second coating is formed from the second composition; the first composition is suitable for applying the first coating to the metallic substrate, and is characterised in that the first composition comprises a carrier medium and graphene platelets, in which the first coating comprises between 0.002 wt % and 0.009 wt % of the graphene platelets, and the graphene platelets comprise one of or a mixture of graphene nanoplates and/or graphite flakes in which the graphite flakes have one nanoscale dimension and 25 or less layers, wherein more than 50% of the graphene platelets have an electrical conductivity greater than 2.15×107 S/m at 20° C., and the carrier medium is an electrical insulator; and the second composition comprises a carrier medium and graphitic platelets in which the second coating comprises more than 0.1 wt % of the graphitic platelets, and in which more than 50% of the graphitic platelets of the second coating have an electrical conductivity of less than 2.0×10−5 S/m at 20° C.
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