Nitrogen plasma immersion ion implantation on NiTi SMA

NiTi alloys are considered as ‘‘smart functional materials’’ exhibiting shape memory and superelasticity effects with applications in many areas such as aerospace, robotic and medicine. Although the NiTi alloy is an intermetallic compound with strong atomic bonding, but for medical application the Ni ion release is still a major concern due to its eventual toxicity.  This work will show the effects of the surface modification by nitrogen plasma immersion ion implantation. Recently published literatures indicate that Ni release can be suppressed by this technique and successful “in vivo” tests have been performed. Other surface improvements (mechanical as well as tribological) are expected by obtaining subsurface TiN formation. The nitrogen implanted samples will be analyzed by DSC, Auger Spectroscopy, SEM, tribometer, nanoindenter and AFM.