DC glow discharge plasma nitriding is the process of surface hardening through the spread of nitrogen atoms to the metal surface under special conditions of the plasma nitriding. Titanium and titanium alloys are the most common alloys used in medical applications. Titanium and its alloys are lightweight, corrosion resistant, and have good fatigue properties but lack wear resistance under aggressive environments. The plasma nitriding process was used for a titanium alloy (Ti–6Al–4V) rod with different parameters at a vacuum chamber of air (2 mbar), 680 volts and 30 mA. The plasma nitriding process was performed at different nitriding times (5, 10, and 15 h), and the effect of plasma nitriding was examined on the chemical compassion of Ti–6Al–4V alloy and the appearance of phases was studied by optical microscopy (OM), scanning electron microscopy and field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), Tafel potential polarization, and cyclic polarization. The results indicate that the formation of layers and phases Ti2N and Ti2N3−x on a surface of the alloy were achieved, which would improve the surface characteristics of chemical corrosion in simulated body fluid.
The aim of this study is to evaluate the corrosion resistance of the Ti–6Al–4V alloy in simulated body fluid by using DC glow plasma nitriding at the different nitriding times.
The results obtained from polarization curves suggest that the plasma-nitrided Ti–6Al–4V alloy for different nitriding times improved corrosion resistance in a SBF when compared with the untreated alloy. These improvements can be seen from the low current density and low passive current density obtained at 10-h nitriding.Prof. Dr. Eng Ali Sabea Hammood, PhD
Journal of Bio- and Tribo-Corrosion