Corrosion resistance behavior of Ti/TiN multilayer coatings deposited on Ti6Al4V substrates

Abstract

DC magnetron sputtering was used to deposit titanium (Ti), titanium nitride (TiN), and Ti/TiN multilayer coatings on Ti6Al4V alloy substrates. The multilayer coatings have 1, 4, 10, 16, 32 modulation periods respectively. SEM were used to analyze the surface and cross-sectional micro-features of the coatings. Electrochemical tests were carried out 3.5 wt% NaCl solution at room temperature. The resistance of the coating reaches the maximum value, which is 6 times that of the substrate, 2.4 times that of a single layer of titanium, and 5 times that of titanium nitride. With the increase of the modulation period, the charge transfer resistance of the Ti/TiN multilayer coatings increase firstly and then decreases, and charge transfer resistance reaches the maximum at the period of 4, which is closely related to the surface morphology.