Study on interfacial bonding strength of TiN films prepared by magnetron sputtering at low temperature

Reactive magnetron sputtering technique was used to gain titanium nitride (TiN) films on W18Cr4V high-speed steel and GCr15 bearing steel substrates at low temperature. The Surface chemical composition of the films was analyzed using energy dispersive X-ray spectroscopy (EDXS) and the surface morphology was examined using atomic force microscopy (AFM). Moreover, a series of experiments have been conducted to study the relationship between interfacial bonding strength and some major technological parameters, that is, substrate surface roughness, negative bias voltage, intermediate transition layer, substrate hardness, and ion etching before deposition. The experimental results have indicated that the TiN film with typical ratio of chemical metric can be deposited on substrates using reactive magnetron sputtering technique below 140 degrees C. The AFM image has showed that the TiN film using magnetron sputtering technique was composed of densely distributed nano-grains with uniform structure. Its surface was flat and smooth. The indentation testing results have showed that the increase of surface roughness and substrate hardness improves the bonding strength of TiN / substrate significantly. Furthermore, the bonding strength of TiN / substrate can also be improved through the following methods: (1) choosing a proper intermediate transition layer; (2) adopting ion etching before deposition and (3) increasing negative bias voltage before deposition.