Properties of Titanium Oxynitride Prepared by RF Plasma

Abstract

Titanium oxynitrides combine the properties of metallic oxides and nitrides. In this presentation, titanium was oxynitrided using inductively coupled RF plasma in a gas mixture containing 80% N 2 and 20% O 2 . The effect of plasma-processing power from 350 up to 550 W on microstructure, mechanical, tribological, wettability and electrochemical properties of the oxynitrided titanium was examined using different characterizations and testing techniques. The results demonstrated the formation of TiO, TiO 2 rutile phase, TiN x O y and Ti 2 N as a result of plasma oxynitriding. The micro-hardness of the oxynitrided layers increases up to 766 HV 0.1 as the plasma-processing power increases up to 550 W. The wear and corrosion resistance are improved for oxynitrided titanium in comparison with untreated samples. Moreover, the friction coefficient decreases from nearly 0.75 for the pure titanium to nearly 0.3 for oxynitrided titanium. The obtained data show an increase of surface energy and wettability of titanium oxynitride as the plasma power increases. The formation of hard oxide and oxynitride phases and the transformation of TiO 2 from anatase to rutile structure at relatively high temperature are the main reasons for the good physical and electrochemical properties of titanium oxynitride.