A detailed chemical analysis of the FGO and GO powders and filtrates (post-dispersion in the copper plating solution) is provided in the ESI. Alongside the information obtained on the coatings, a mechanism for the deposition of FGO-CMMCs and GO-CMMCs onto AISI 52100 steel can be tentatively proposed (Figure ). The example below focuses on the use of GO within the mechanism for clarity but can also be interpreted for FGO inclusion. Evidence from XRD, Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) shows that in the production of the plating dispersion, the carboxylic acid groups on (F)GO nanosheets are functionalized by a K + salt in the solution, resulting in an edge-functionalised nanosheet. The nature of the ion functionalisation is not clear, but XPS evidence suggests that a form of (K + ) x (CO 3 ) x is present. The functionalisation of the graphitic nanosheets also aids in stabilising the plating dispersion to aggregation. During deposition, the metallic moieties on the functionalized graphenes anchor to the growing copper film by edge interactions. With continued growth, the GO nanosheet binds to the growing copper film in a passive manner. There is no further chemical activation of the nanosheet surface (namely at the alkoxy/epoxy sites), inhibiting any CuNP nucleation on its surface. The binding interface between Cu and the nanosheets may induce a nucleation site for further copper growth, growing misorientated grains that embed the nanosheet within the film.