Si content dependent microstructure and mechanical properties of CrN/TiSiN nanomultilayered films

By incorporating TiSiN modulation layer, CrN/TiSiN nanomultilayered films with different Si contents were synthesized by reactive magnetron sputtering, keeping the fixed modulation period and modulation ratio. The effect of Si content on microstructure and superhardness effect of CrN/TiSiN nanomultilayered films was investigated. With low Si content, the TiSiN layers exhibit fcc structure under the “template effect” of CrN layers and grow epitaxially with CrN layers, leading to improvement of crystallization degree of nanomultilayered films and superhardness effect. The maximum values of hardness and elastic modulus reach 34.6 GPa and 426 GPa, respectively, with Si:Ti ratio of 7:18. As the Si content further increases, the amount of SiNx phase in TiSiN layer increases and SiNx phase transforms into amorphous state, leading to the amorphous characteristic of TiSiN layers, which breaks epitaxial growth structure between CrN and TiSiN layers and decreases mechanical properties of CrN/TiSiN nanomultilayered films.