Microstructure and mechanical properties of reactively sputtered Ti(O,N) coatings

A series of Ti(O,N) coatings with different oxygen content were deposited by the reactive magnetron sputtering method in a gaseous mixture of Ar, N2 and O2. Energy dispersive spectroscopy, X-ray diffraction, scanning electron microscopy, atomic force microscopy and nanoindentation were employed to investigate the effects of oxygen partial pressure on chemical composition, microstructure and corresponding mechanical properties of Ti(O,N) coatings. Experimental results showed that with increasing oxygen partial pressure, the oxygen content gradually increased in coatings and the nitrogen content decreased correspondingly. During the process, these coatings remained a similar NaCl structure as TiN. Coating hardness fluctuated in the range of 21–28 GPa and achieved its maximum value at 5.0 at.%O.