Tailoring microstructure, mechanical and tribological properties of NiTi thin films by controlling in-situ annealing temperature

Magnetron sputtered near equiatomic NiTi thin films were deposited on Si (100) and hot work tool steel substrates. The deposited thin films were in-situ annealed at four different temperatures viz., 80 °C, 305 °C, 425 °C, and 525 °C. The effect of the in-situ annealing temperature on the microstructure of the film, the morphology, as well as mechanical and tribological properties was studied using X-ray diffraction, synchrotron diffraction, transmission electron microscopy, energy dispersive X-ray spectroscopy, ball-on-disc, scratch test, and three dimensional optical microscopy. The obtained results revealed how the variation of in-situ annealing temperature affects the crystallization, microstructure evolution, as well as mechanical and tribological properties of NiTi thin films. - Highlights: • In-situ annealed thin films at 80 °C are amorphous with poor tribological behavior. • In-situ annealed thin films at 305 °C have metallic glasses coating materials. • In-situ annealing above 425 °C resulted in the formation of shape memory effect. • In-situ annealing at 305 °C and 525 °C resulted in an excellent tribological behavior.