Fabrication and characterisation of graphene-based multi-functional coatings

This research was aimed at exploring different surface engineering techniques towards cost-effective and scalable fabrication of graphene-based coatings on metallic surfaces. Graphene oxide (GO) was employed as the coating precursor, and various coating routes, including electrophoretic deposition (EPD), self-assembly, electroplating and electro-brush plating were investigated in the project. The results have showed that both EPD and self-assembly are capable for depositing thin and uniform GO coatings on steel. The tribological and corrosion tests on EPD-GO coatings have showed promising properties of the GO coatings. It has also been found that pre-modification of the steel surface with a self-assembled monolayer of silane can also enhance the bonding of the GO sheets to the steel surface, thus improving the wear performance of the ultra-thin GO coating. The electro-brush plated Ni-GO nano-composite coatings have exhibited significantly improved compactness and homogeneity. A grain refinement and improvement in mechanical properties were observed. More importantly, the GO-containing nano-composite coatings have exhibited enhanced thermal stability after annealing at elevated temperatures up to 600 ℃. Meanwhile, the Ni-GO composite coatings showed clearly improved tribological and anti-corrosion performance. The findings indicate that electro-brush plating is a very promising technique to produce novel nano-composite coatings.