Corrosion behavior of TiN monolayer and CrN/TiN multilayer coatings: Impact of immersion time and saline solution type

Abstract The corrosion behavior of the TiN monolayer and CrN/TiN multilayer coatings deposited via cathodic arc evaporation physical vapor deposition (CAE‐PVD) on the Ti–6Al–4V substrates were evaluated in Ringer's and Hank's physiological saline electrolytes. XRD (x‐ray diffractometry) and scanning electron microscopy (SEM) analysis were used to characterize the coatings. The corrosion behavior of coatings was assessed by impedance spectroscopy and potentiodynamic polarization techniques. The results showed that the corrosion resistance of coatings was increased in the order of TiN‐Ringer's < TiN‐Hank's < CrN/TiN‐Ringer's < CrN/TiN‐Hank's. Therefore, it can be concluded that the CrN/TiN coating, due to having a large number of interfaces and a smoother surface with fewer macroparticles and pinholes, is more efficient in raising the corrosion resistance properties of titanium than TiN monolayer coating. Moreover, it was observed that Ringer's solution is a more severe environment than Hank's solution. Both coatings, because of the precipitation of a protective corrosion products layer on their surface, showed an enhancement in corrosion resistance with increasing the immersion time from 1 to 14 days in Hank's. The results suggest TiN monolayer and CrN/TiN multilayer coatings as promising candidates for biomedical applications.