Characterization of sputter-deposited TiPdNi thin films

TiPdNi thin films were prepared by magnetron sputtering onto unheated glass and silicon substrate. Atomic force microscope, energy-dispersive X-ray microanalyzer, X-ray diffractometer, differential scanning calorimeter and optical microscope were used to characterize the films. It is found that the surface morphology of the films change during the sputtering process and a shift of about 3% Ti (mole fraction) content from the center to the edge of the substrate occurs. The freestanding as-deposited films undergo crystallization followed by three kinds of cooling conditions. For all these heat-treated films, B2-->B19-->B19' two-stage phase transformation takes place. Many Ti2Ni and Ti2Pd type of precipitates are detected in the films. The constraint films on silicon substrate are crystallized at high temperature. After crystallization, the films show a two-way shape memory effect.