Influence of in-situ and postannealing technique on tribological performance of NiTi SMA thin films

•NiTi SMA thin films post and in-situ annealed under same annealing conditions.•In-situ annealed treatment leads to faster formation of crystalline NiTi SMA thin films.•In-situ annealed thin films have a higher coating-to-substrate adhesion strength.•In-situ annealed thin films possess much better wear resistance capability.

Magnetron sputtered NiTi thin films were crystallized through two convenient techniques: (i) postannealing and (ii) in-situ annealing during the deposition. The annealing parameters (temperature and time) were kept constant by employing each technique. The microstructure, morphology, phase transformation behavior, mechanical and tribological properties of these thin films were investigated using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), 4-point probe resistivity measurement, nanoindentation test, pin-on-disc, scratch test and three dimensional (3D) optical microscopy. The results show how postannealing and in-situ annealing techniques can differently affect properties of NiTi thin films in spite of employing similar annealing temperature and time.