D. bronfenbrenner, Corning Inc., Painted Post, NY; V. Radmilovic, Lawrence Berkeley National Labs, Berkeley, CA; S. A. McHugo, Nitinol Devices & Components, Fremont, CA; R. Gronsky, University of California, Berkeley, CA
Sputter deposited NiTi thin film has shown great promise in biomaterial applications for its biocompatibility, superelasticity, and shape memory properties. As the number of applications for this material increases, it is important to verify the consistency of the sputter deposited films at the microstructural level. As-deposited crystalline thin film NiTi was analyzed to determine the phase distribution, microstructure, and transformation properties at given sputter deposition parameters. Transmission electron microscopy and x-ray diffraction were used to assess the phase distribution and microstructure of the thin film product. In addition, the transformation properties were studied using differential scanning calorimetry and atomic force microscopy. The films were shown to have a phase distribution of approximately 90% martensite and 10% R-phase, a grain size of 100-500 nm, and an Af of 80oC.
As-deposited crystalline NiTi thin films are analyzed by transmission electron microscopy, x-ray diffraction, and differential scanning calorimetry to determine their dominant phases, microstructure, and transformation behavior as a function of sputter deposition parameters. It is found that the NiTi films are in the twinned martensite phase at room temperature with an average grain size of ~100 nm and a columnar microstructure
