Characterization of TiN, TiC and TiCN coatings on Ti-50.6 at.% Ni alloy deposited by PIII and deposition technique

The advanced plasma immersion ion implantation and deposition (PIII&D) method has been used to deposit TiN, TiC and TiCN films on the surface of Ti-50.6 at.% Ni alloys. Smooth surface with root mean square (RMS) roughness of values 2.672 nm for the TiN, 1.517 nm for the TiCN film and 5.339 nm for the TiC film have been obtained. The XPS Ti 2p, C 1s and N 1s peaks and the valence band spectrum show that the nitrogen, carbon, carbon combined with nitrogen is fully bonded to titanium as nitride, carbide and carbonitride, respectively. Based on the electrochemical measurement and ion releasing tests, we can conclude that the treated samples exhibit better corrosion resistance and depress Ni ion release from the NiTi alloys in the Hank's solution at 37 degrees C.The suppression of Ni ion by the films is a beneficial phenomenon for the future application of NiTi alloys in the biomedical field. (C) 2006 Elsevier B.V. All rights reserved.