In this research the effect of plasma nitriding and physical vapor deposition processes on the surface quality of Ti-6Al-4V was studied. During the plasma nitriding, the samples were treated at temperatures of 750 o C, 850 o C and 950 o C in a gas mixture of 74.9%H 2 and 25.1%N 2 at pressure of 5mbar for a period of 20 hours. The results indicate that, the hardness and roughness of the samples increase with increasing the temperature and temperature has a dramatic effect on the formation of phases and their intensities. At different temperatures various amounts of nitrogen solid solution in titanium, Ti 2 N and TiN phases were formed and the maximum amount of TiN was obtained at 950 o C. In the coating process with physical vapor deposition, the samples were coated with two methods. In the first method the samples were coated with conventional EB-PVD at 500 o C and in the second method with modified EB-PVD at 500 o C and 700 o C. The difference between these methods is the application of ion bombardment in the second method. The growth behavior of these coatings was evaluated with respect to structure-zone models. The hardness of sample prepared in 700 o C was much higher than the two other samples. It was observed that the interface of this sample was in the form of zigzag, while the other samples had flat and abrupt interfaces. Furthermore, with increasing the temperature and applying the ion bombardment, the relative texture was changed from (111) to (200) planes.
