Microstructure, Interface and Hardness of Ti/TiN Nanolayered Coatings

Abstract

The polycrystalline Ti/TiN multilayer films were deposited by magnetron sputtering. We investigated the effects of mixed discharge gas pressure, bias voltage and substrate temperature on the microstructural, interfacial, and mechanical properties of the polycrystalline Ti/TiN multilayer films. X-ray reflectivity and diffraction (XRR and XRD), and nanoindentation were used to characterize the structures and mechanical properties for the films.The period of multilayer, interface width and grain size decrease with increaseing of deposition pressure. The multilayer coating at floating voltage shows TiN (111), Ti2N (103), and TiN (200) preferred crystalline orientation, whlie those at other different substrate biases show only TiN (111) and Ti2N (103) preferred crystalline orientation. It was found that the hardness increased with increasing substrate temperature. This hardness enhancement was probably caused by the modulus difference in the interface between layer Ti and TiN or the preferred crystalline orientation TiN(111).