FGO-Copper and GO-Copper plating dispersions were prepared by loading the basic copper plating solution with FGO or GO powders to achieve a 1 mg/mL dispersion, followed by ultrasonication for two hours (Elmasonic P70H, 37 kHz amplitude, 100% power) and storage. Before use, the dispersions were agitated by sonication for 15 minutes. SKF LS-1528 (AISI 52100, 28mm OD, 15 mm ID, 2.75 mm thick) and LS-2542 (AISI 52100, 42 mm OD, 25 mm ID, 3.00 mm thick) raceway washers were purchased from shop.Eriks.co.uk. 8 mm diameter, 52100 ball bearings (Grade 10: Ra ≤ 25 nm) were purchased from Simplybearings.co.uk. Both the 52100 washers and ball bearings are used as supplied. The 52100 washers and ball bearings were cleaned before use by successive ultrasonic cleaning steps in isopropanol (twice) and acetone followed by freeboard drying.