In comparing the average CoF during PoD sliding (Figure ), it is clear that ML (Ni) coatings provide a high load-bearing, long-lasting and low friction lubrication surface, with μ < 0.2 after 10,000 revs of sliding at 25N (≈ 1.15 GPa), this is in contrast to both ML (Cu) , which showed marginal friction reduction and poor lifetimes at lower contact pressures, and GnPfree ML (Ni) , which showed no lubrication performance and experienced high rates of wear to expose the underlying steel at low loads. This supports the theory that the hybrid coating system, comprising of a (GnP-Cu)/Ni multilayer matrix composite is promoting synergy during solid lubrication. Although it is clear to see that the nickel-flashed ML (Ni) coating shows superior friction and wear reduction at > 1 GPa contact loads, the tests above do not elucidate the reasoning behind the differences in performance between ML (Ni) and ML (Cu) . Due to the high levels of damage on the tracks after 10,000 revs sliding, the amount of post-test information available from the coatings is limited, and would be difficult to compare without significant assumptions made.