Structural Investigation of Ti-N Films

Abstract

ABSTRACTTi-N films were deposited by reactive ion plating on various substrates. The N/Ti-ratio was systematically varied in order to produce films of varying structure and properties from pure titanium to overstoichiometric TiN. Broad diffraction peaks typical of PVD Ti-N films were found. Metastable ct-titanium was observed over a wide range up to about 50 at. % N. No marked differences in the phase composition or in the crystallographic texture could be found in the films deposited on the various substrates. The hardness of the films was observed to increase with increasing nitrogen content, reaching a maximum around 35 – 40 at. % N corresponding to a mixed ε-Ti2N and δ-TiN structure. Extended annealing at 773 K did not result in any major phase transformations. After annealing at 1173 K, α-Ti could no longer be found in nitrogen-rich films. Also ε-Ti2 N transformed to δ-TiN after annealing at 1173 K for 2 h.