TiNi thin films prepared by cathodic arc plasma ion plating

The TiNi intermetallic compound possesses shape memory effect and pseudoelasticity. The demand for integration and the high price of TiNi alloys necessitate their application as a surface layer upon base materials. In this study, an attempt was made to obtain high quality TiNi film using the CAP process. Substrate bias voltage, working pressure and target composition were changed to understand the relationship between the coating parameters and film microstructure. The microstructures of the deposited films were characterized using XRD and TEM. SEM was used to observe the surface and cross sectional morphology of the films. EDS was used to analyze the composition of the films. DSC was used to understand the thermal behavior of the deposited films. The experimental results show that TiNi films can be prepared using a CAP process. When the negative bias voltage is high enough, crystalline TiNi film can be deposited using CAP without heat treatment. Phases existing in the deposited film depend strongly on the target composition and the crystallinity of the deposited film depends strongly on the substrate bias voltage. After 450°C heat treatment for 4 h, the martensitic transformation temperature of all of the corresponding films was increased to room temperature due to thermal healing of defects.