Microstructure and mechanical properties of Ti(C, N) and TiN/Ti(C, N) multilayer PVD coatings

Magnetron sputtered Ti(C, N) and TiN/Ti(C, N) multilayer coatings are deposited onto cemented carbide substrates at 350 degrees C. The crystal structure and microstructure of the deposited coatings are characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), nanoindentation and scratch test. XRD examination indicates that both coatings are of fcc structure. In accordance with SEM observation, both coatings are columnar crystallites structures and the TiN/Ti(C, N) multilayer coating forms the modulation structure with alternating TiN and Ti(C, N) layers. As for TiN/Ti(C, N) multilayer coating, the hardness and adhesion with substrate are improved due to interface effect between TiN and Ti(C, N) layers. Ti(C, N) and TiN/Ti(C, N) multilayer coatings exhibit approximately identical performance and different failure forms in machining carbon steel. But the performance of TiN/Ti(C,N) multilayer coating inserts in machining stainless steel is superior to Ti(C,N) coating inserts due to the better thermal stability of TiN/Ti(C,N) multilayer coating. (C) 2007 Elsevier Ltd. All rights reserved.