Influence of substrate roughness on adhesion of TiN coatings

Titanium-nitride coatings were prepared by ion beam assisted deposition. In order to provide adequate adhesion between TiN films and steel substrates, ion beam mixing of Ti atoms with atoms of steel base was applied prior to deposition. The effect of substrate surface roughness on adhesion strength of TiN coatings was evaluated in this research. A scratch test was used to characterize the adhesive properties of the coatings. Optical microscopy was employed to examine scratch-induced channels, while atomic force microscopy was used to determine sample roughness prior and after the deposition of TiN coatings. It has been revealed that adhesion increases with increase in substrate roughness.