Comparison for mechanical properties between TiN and TiAlN coating layers by AIP technique

TiN and TiAlN coating layers were fabricated on SKD 11 steel substrate by an arc ion plating (AIP) technique. The mechanical properties such as hardness, impact, and wear were comparatively examined between TiN and TiAlN coating layers. Those layers were fairly adherent to SKD 11 steel substrate, and showed hardness values of 2300±100 and 3200±100 kg/mm2 with a load of 25 g, respectively. TiAlN coating layer showed much superior impact wear resistance to TiN layer. It could be suggested in this work that the TiN coating layer was failed relatively by plastic deformation with oxidation during impact test, while TiAlN coatings was failed by brittle fracture and resisted the oxidation by impact energy. However, TiN coating layer showed better the abrasive wear resistance than TiAlN. The friction coefficient of TiAlN films was higher than that of TiN films and considerably increased with increase of relative humidity due to the tribochemical reaction.