Mechanical and tribological properties of multilayered PVD TiN/CrN, TiN/MoN, TiN/NbN and TiN/TaN coatings on cemented carbide

Four different multilayered coatings TiN/CrN, TiN/MoN, TiN/NbN and TiN/TaN, were deposited on cemented carbide. A hybrid PVD process consisting of ion plating (TiN) and magnetron sputtering (CrN, MoN, NbN and TaN) was used. The chemical and phase composition, morphology and microstructure of the coatings were assessed using auger electron spectroscopy, X-ray diffraction, scanning electron microscopy and transmission electron microscopy, respectively. In addition, all coatings were characterised with respect to their residual stress, hardness, cohesion/adhesion and abrasive wear resistance. A PVD TiN coating was used as a reference throughout the investigation. All coatings exhibited a cubic NaCl structure. Furthermore, ail multilayered coatings, except TiN/MoN, were found to have a strongly preferred (200) orientation. TiN/MoN displayed a mixture consisting of (111), (200) and (220) orientations. TiN displayed a (111)-preferred orientation. It was found that the mechanical and tribological properties of the multilayered TiN/metal nitride coatings, in general, were superior to those of homogenous TiN. The overall best performance was found for the TiN/CrN coating, whereas TiN/TaN showed the highest abrasive wear resistance. (C) 1998 Elsevier Science S.A.