Tribological Behaviour and Cutting Performance of PVD-TiN Coating/Substrate System with Discontinuous Surface Architecture

Abstract:

TiN coating was deposited by arc evaporation PVD (physical vapor deposition) onto tool steel. A netted screen made of the stainless steel was placed between substrate and vaporizer in order to get discontinuous TiN coatings. Three kinds of surface condition (uncoated, continuous and discontinuous TiN coatings) were prepared and examined for their performance. Tribological behavior was investigated by means of dry and lubricated sliding tests at room temperature and 200 °C, on a disk-on-block and sphere-on-flat tribometer. The results show that the discontinuous TiN coating significantly decreases both the wear and the wearing speed of tool steel under sliding tests, and reduces friction under conditions of bidirectional sliding. In the three kinds of surface condition, the discontinuously coating has superiority for high speed cutting owing to its lifetime increasing compared with uncoated and continuously coated.

Key words:PVD; continuous coating; discontinuous coating; tribological behaviour; roughness; cutting performances