Electrochemical Corrosion Behavior of Powder Metallurgy Ti6Al4V Alloy

The corrosion behavior of powder metallurgy (PM) Ti6Al4V alloys with different relative densities ranged from 95.2 to 99.5% is investigated in 3.5 wt.% NaCl solution at room temperature by electrochemical methods, including potentiodynamic polarization curves and electrochemical impedance spectroscopy. For comparison, traditional wrought Ti6Al4V alloy with full densification is also investigated. The results show that the corrosion resistance of PM Ti6Al4V alloys increases with the increasing density. All the studied samples exhibit low Ip values (in the order of 10−6 A cm−2), indicating good corrosion resistance under current experimental conditions. Therefore, density effect on the corrosion resistance of PM Ti6Al4V alloys is less significant. It is worth noting that the corrosion resistance and mechanical performance of PM Ti6Al4V alloys with nearly full densification are comparable to those of wrought alloys. Therefore, PM Ti alloys are promising candidates in the marine application.