Patterned PVD TiN spot coatings on M2 steel: Tribological behaviors under different sliding speeds

Experiments were performed to investigate systematically the influence of sliding speeds on tribological behaviours of in-lined (IN), staggered (ST) spot-islandic and fully coated (FC) physical vapour deposition (PVD) TiN coatings on M2 steel discs sliding with ASSAB 17 tool steel pins. Results revealed that: (i) the friction coefficients of the individual mating couples generally decreased with the sliding speed and the order in increasing magnitude at each specific sliding speed was FC, IN, and ST pair, respectively and (ii) the wear loss was inversely related to the sliding speed, and the wear loss of both the pin and disc of FC mating pair was the largest with ST the second and IN the third. Relevant mechanisms for the friction and the wear loss are proposed and discussed in this paper.