Both GO-CMMC (0.25CD) and GO-CMMC (0.5CD) achieve a near-immediate low-friction sliding (μ ≤ 0.2) for a short period (approx. 750 revs), before lubrication fails and unstable, high-friction sliding modes are observed. In contrast, FGO-CMMC coatings show superior friction throughout the test period; a near-instant low-friction regime was observed at the start of FGO-CMMC (0.25CD) , sliding, and μ remained below 0.2 until tests were stopped at 10,000 revs of sliding (Figure ). FGO-CMMC (0.5CD) displays similar low-friction running at the start of the sliding tests, but its performance fatigues after ~4,300 revs, followed by a slow rate of μ increase to ~0.25 by the end of testing. The sliding tests conclude that the incorporation of graphene oxide into a copper composite can generate a low-friction sliding surface. However, the longevity of the low-friction phase is owed to the function of the fluorinated groups in FGO.