Electroplating of the FGO-CMMC, GO-CMMC and Cu Ref coatings onto the 52100 substrates was achieved using an electroplating assembly (Figure ). The assembly consisted of a 400 mL tall form Borosilicate glass beaker, with 200 mL of plating solution and a magnetic stirrer to ensure homogenous mixing during electroplating. Four Cu sheets (approx. 20 x 1 x 200 mm) were evenly spaced around the inside perimeter of the beaker and connected to act as the anode. The cathode was made from a masked AISI 52100 washer, suspended in the plating solution using Cu wire. The current density was controlled using a current-limited power supply (Agilent E3631A). To assist with uniform FGO-CMMC and GO-CMMC co-plating, a 100 nm nickel flash layer was deposited (Watts solution, 1 A/dm 2 , 30 secs) onto the AISI 52100 washer before Cu-plating. After washing the Ni-flashed 52100 substrate with water and isopropanol, it was plated in the respective plating dispersions/solutions for FGO-CMMC, GO-CMMC and Cu Ref deposition experiments. The current density and deposition time were adjusted to achieve ~20 μm-thick coatings on the washer (0.25 A/dm 2 for 6 hours, or 3 hours at 0.5 A/dm 2 ). After completing a deposition, each coating was stored with silica gel to inhibit oxidation.