Edge Related Effects during Ion Assisted PVD on Sharp Edges and Implications for Coating of Cutting Tools

During ion assisted physical vapour deposition on sharp edges and corners, interaction between the plasma and the samples can lead to significant changes in the morphological and compositional properties of the coatings in the edge region. These edge related effects were studied on wedge shaped samples coated with TiAlN/VN coating in an industrial deposition process using low energy high flux Ar⁺ ion irradiation (J_i/J_me∼4, E_i = 75 - 150 eV). The magnitude and spatial extent of edge related changes are directly related to the characteristics of the plasma sheath around the edges. The influence of the edge geometry and the deposition conditions (substrate bias) is examined, as well as the implication for the coating of cutting tools.