Multilayer nitride coatings by closed field unbalanced magnetron sputter ion plating

A range of ceramic multilayer nitride coatings, including NbxTiyN, NbxZryN, and MoxZryN, has been successfully deposited onto tool and die steels by closed field unbalanced magnetron sputter ion plating. The mechanical properties of the resulting coatings, including adhesion and hardness, have been evaluated by micro- and nano-indentation techniques, scratch testing etc. HPlast hardness up to 53 GPa has been achieved in the case of the NbxTiyN multilayers, 43 GPa for NbxZryN and 38 GPa for MoxZryN. The detailed microstructure of the coatings, including their respective nm-scale multilayer repeat distance, Λ, has been studied by advanced analytical techniques including high resolution transmission electron microscopy, ion backscattering (Rutherford, and non-Rutherford), and glancing angle X-ray diffraction, and focused ion beam machining and imaging. The coating properties are reviewed and correlated with the analytical data. Potential applications for, and some limitations of, the selected coatings are discussed.