Anti-corrosion and electrically conductive inorganic conversion coatings based on aligned graphene derivatives by electrodeposition

Ultrathin conversion coatings, made from aligned graphene derivatives and ammonium zirconium carbonate (AZC), were fabricated on stainless steel by electrodeposition. Sulfonated graphene oxide (SGO) provided electron pathways and physical barriers to corrosive molecules. Electrodeposition ensured the alignment of SGO and the facile fabrication of the coatings. AZC is an environmental-friendly crosslinking agent, water-repellent and corrosion inhibitor. Upon dehydration reactions, AZC improved the cohesion between SGO layers and anchored the conversion coatings on metal substrates. When the mass ratio of SGO to AZC was 2:1, the corrosion current density of the composite coatings reached 0.098 ​μA ​cm⁻², while that of the bared stainless steel was 1.04 ​μA ​cm⁻², given a coating thickness of only 500 ​nm. The electrical conductivity of SGO/AZC composite coatings can be tailored from 3.84 ​× ​10⁻⁵ to 2.28 ​× ​10⁻³ ​S‧cm⁻¹ by heat treatment and HI reduction, which satisfied the electrical conductivity requirement of wide applications in electronic industry, office appliances and petroleum storage.