The influence of the surface morphology of titanium aluminum nitride (TiAlN) films, on the hardness and corrosion behavior, was investigated using atomic force microscopy (AFM), scanning electron microscopy (SEM), nano-indentation and potentiodynamic test. With increasing substrate bias voltage and nitrogen flow rate the originally porous and rough surface morphology of the TiAlN films was transferred into a dense and smooth structure. The root mean square (RMS) roughness of the TiAlN films measured using AFM decreased from 3.6 nm to 2.0 nm as the substrate bias was increased from 25 V to 100 V. The experimental results showed that the corrosion resistance and hardness of the coatings increased with decreasing surface roughness. These increases at high substrate bias and high nitrogen flow rate were attributes to the decrease in atomic distance and the reduction in surface porosity.

Keywords: TiAlN, Bias, Nitrogen, Morphology, Roughness, Hardness, Corrosion.