Chemical vapor deposited TiCN/TiC multilayer coatings: On the interplay between coating architecture and mechanical properties

Abstract

Modifying the architecture from a monolithic to a multilayered structure allows adjusting the mechanical properties and cutting performance of industrially relevant hard coatings. The present work focuses on the microstructural, micro-mechanical and cutting performance evaluation of a multilayered TiC 0.67 N 0.33 /TiC coating grown by chemical vapor deposition. Energy dispersive X-ray spectroscopy and atom probe tomography confirmed the presence of individual TiC and TiC 0.67 N 0.33 layers of ∼120 nm thickness with well-defined interfaces. The overall C/(C + N) ratio of the coating amounts to 0.82. Individual peaks for the TiC 0.67 N 0.33 and the TiC layer can be observed in the X-ray diffractogram of the TiCN/TiC coating. Scanning electron microscopy showed that the grains grow through the interfaces between the TiCN and TiC layers. Finally, the micro-mechanical properties and cutting performance of the TiCN/TiC multilayer were compared with a monolithic TiCN coating. The fact that the TiCN/TiC coating outperformed the monolithic reference TiCN in regard of hardness and cutting performance emphasizes the high potential of multilayered coatings for use in demanding applications. • TiCN/TiC multilayer coating with layer thickness of 120 nm grown by CVD. • Increased overall C/(C + N) ratio as compared to state-of-the-art CVD TiCN coatings. • Better hardness and cutting performance in multilayer as compared to reference TiCN.