Correlation between the surface characteristics and the duty cycle for the PACVD-derived TiN nanostructured films

Abstract

In recent years, plasma-assisted chemical vapor deposition (PACVD) has been identified as a suitable technique to deposit hard coatings on tools of complex geometries. This study sheds light on the influence of the duty cycles on the surface characteristics of the nanostructured TiN coatings for the first time. A mixture of H 2, N 2, Ar, and TiCl 4 was used to deposit a thin film of TiN on the H13 steel. The micro-structural, mechanical, and tribological properties of the coating were investigated using atomic force microscopy (AFM) and scanning electron microscopy (SEM). Applying higher duty cycles resulted in formation of rougher surfaces. It was also revealed that the grain size increased with the duty cycle. Moreover, the film's thickness was measured as 1.6–2.3 μm, depending on this parameter. A hardness of 1723 HV 0.05 was obtained when the layer was fabricated at the lower duty cycles. Meanwhile, the corrosion resistance of TiN coatings grown under a low duty cycle was higher than that of the layers fabricated at higher duty cycles.