Shape memory behavior of high temperature Ti-Ni-Pt thin films

Titanium-nickel-platinum (Ti54Ni26Pt20) thin films shape memory alloys are produced using direct current magnetron sputtering process. The films are deposited on a (100) silicon substrate with 500 nm of wet thermal oxide layer. As-deposited amorphous films are crystallized at 550 deg. C and 600 deg. C for 1 h. X-ray diffraction shows that the structure of the martensitic phase is orthorhombic (B19). Both films exhibit classic shape memory effect. The transformation temperatures for the films are above 300 deg. C, the film annealed at 600 deg. C has higher transformation temperatures which are attributed to the presence of large precipitates not found in the film annealed at 550 deg. C