(5N) testing, several key features can be identified (summary of results in Table ). First, the copper content is high (~ 60 at.%), as it constitutes the bulk of the coating. The carbon content on the surface of the wear tracks is in the region of 30-33 at.%; considerably higher than the < 1 wt.% (≈ 4.5 at.%) identified within the bulk of the coating by elemental analysis.