Deposition of superelastic composite NiTi based films

• We develop a carbon rich TiCN coating.
• We develop NiTi coatings with shape memory and superelasticity effects.
• We develop bilayer NiTi/TiCN coating systems with composite properties.

In recent years, NiTi shape memory alloys (SMA) thin films have been widely used as promising high-performance materials in the field of biomedical and microelectromechanical (MEMS) systems. However, there are still important problems such as their unsatisfactory mechanical and tribological properties including a limited hardness and wear resistance. This study aimed at deposition of layered composite thin films made of NiTi and TiCN thin films on Si (100) substrate by means of DC magnetron sputtering. Subsequently, microstructures, mechanical properties and shape memory behavior of these bilayers were investigated using Nanoindentation, X-ray diffraction (XRD), scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). The results of this study confirmed that the presence of TiCN layer on NiTi thin film modifies its mechanical properties while maintaining the shape memory effects. The initial findings of this research work are suggestive of the potential for fabrication of self-healed composite NiTi based films.