In an attempt to quantify the coating losses versus sliding time, white light profilometry of the formed sliding tracks was obtained. The tracks were found to be smooth and adopt the inverse profile of the stainless steel counterface. On observation of the partial wear tracks formed from 5N sliding, it is clear to see that there is a correlation between wear-depth versus sliding time; both ML (Ni) and ML (Cu) at (5N) coatings show deeper sliding tracks when subjected to longer sliding tests (Figure and Figure ). The ability to provide definitive wear rate information is not possible due to the nature of the coating, as the evolution of the dendritic structure makes quantifying material losses difficult. The dotted-green line represents the "base" of the GnP-Cu layer of the coating (after copper/nickel-topped) that is used as a guide for wear depth; it is difficult to accurately define the penetration depth into the coating without cross-sectioning. Determining the wear rate is further complicated by the evolution of the wear track over time; it is apparent that over increasing sliding times the sliding track becomes dense (Figure ). This is suspected due to the incorporation of the ejected wear debris into the pores of the coating, which is compacted with further sliding and remains in the wear track. At this point, it is not clear if this may help enhance the sliding performance of the coating (by retaining the materials needed for tribofilm formation for longer) or provide hindrance by the limitation for oxidized material ejection. In comparing the rate of wear between ML (Ni) and ML (Cu) at 5N sliding, it is clear to see that