A Comparison of Reciprocating Sliding at Low Loads and Scratch Testing for Evaluation of TiN (PVD) Coating

Abstract

Tribological behaviour of TiN coating deposited on high alloyed tool steel during scratch testing and linear reciprocating testing, at micro Newton loads in dry contact conditions, was investigated in this study. Influence of coating surface roughness on friction coefficient and wear life of TiN coating was studied. The results showed that TiN coating friction and wear behaviour are strongly dependent on its surface roughness. High roughness resulted in adhesive coating failure and higher penetration depth during scratching and lower friction coefficient and higher wear level during sliding. TiN coating with the lowest arithmetic mean deviation of the roughness profile, R-a, 0.01 mu m, exhibited the best adhesion properties and the lowest wear level.