Finally, the wear scars from ML (Ni) (25N) sliding support the findings from ML (Ni) and ML (Cu) (5N) testing: As previously seen in the analysis of ML (Ni) scars formed at 5N load, the surface copper and carbon content remain high (~60 and 30 at.% respectively), with concentrations independent of the sliding time applied. In analyzing the oxygen content, it was seen that between 100-3,200 revs it remains below 4 at.%. However, from 6,400 revs onwards there is a steady increase of oxygen content to over 14 at.% after 20,000 revs. In addition, only once the oxygen content increases at 6,400 revs, do we begin to see the presence of iron, chromium and molybdenum within the coating, as a consequence of 316SS counterface wear from sliding fatigue (Figure ); this was previously observed optically as 316SS debris was found embedded on the surface of the wear track (Figure ).