The Ni-Ti system is the most popular of the SMA's because of its large recovery force, a transformation temperature near room temperature and a good oxidation resistance. Although the transformation frequency is low (mainly limited by thermal inertia), a thin film of Ni-Ti coupled with silicon for heat dissipation can produce cycling frequencies much larger than the typical macrosize structures. The thin films can be electrically driven using joule heating, and they demonstrate fast cooling rates because of their large surface-to-volume ratio. The control of film composition and properties has proven difficult in sputter-deposited films, and a deeper study of deposition techniques is needed. Furthermore, the as-deposited films show an amorphous structure and thus have to be heat treated to induce crystallization in order to have the shape memory effect. In the present study, thin films have been prepared by dc and rf magnetron sputtering. The crystallization of these films has been studied by in-situ grazing incidence X-Ray diffraction (GIXRD), allowing us to establish a correlation between the deposition conditions and the tendency for cristallization.
|Title of host publication||Materials Science Forum|
|Publication status||Published - 1 Jan 2004|
|Event||2nd International Materials Symposium - Caparica, Portugal|
Duration: 14 Apr 2003 → 16 Apr 2003
|Conference||2nd International Materials Symposium|
|Period||14/04/03 → 16/04/03|