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Multi-target sputter deposition of Ni50Ti 50 - XHfx shape memory thin films for high temperature microactuator application

Sanjabi, S ; Sharif University of Technology | 2005

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  1. Type of Document: Article
  2. DOI: 10.1016/j.sna.2005.04.006
  3. Publisher: 2005
  4. Abstract:
  5. High temperature shape memory NiTiHf thin films with varying hafnium contents up to 28.7 at.% were fabricated by DC magnetron sputtering using simultaneous sputter deposition from separate elemental targets. The required film composition was achieved by adjusting the power ratio to the targets. The as-deposited films were amorphous; a post deposition annealing was performed at 550 °C to crystallize the films. Two-micron thick films were characterized by energy dispersive spectroscopy in a scanning electron microscope, temperature controlled X-ray diffraction, differential scanning calorimetry, and atomic force microscopy. The results showed that above 10 at.% Hf additions the transformation temperatures increased considerably over NiTi. The crystallization temperature of the films varied as a function of Hf concentration and was as high as 519.2 °C, at Hf content of 28.7 at.%. The R-phase transformation was observed during cooling at compositions less than 16 at.% Hf. The transformation temperatures confirmed that the films are comparable with bulk NiTiHf alloy of similar composition. © 2005 Elsevier B.V. All rights reserved
  6. Keywords:
  7. Annealing ; Atomic force microscopy ; Cooling ; Crystallization ; Differential scanning calorimetry ; High temperature applications ; Magnetron sputtering ; Microactuators ; Shape memory effect ; Sputter deposition ; Thin films ; X ray diffraction analysis ; DC magnetron sputtering ; High temperature shape memory ; NiTiHf films ; Simultaneous deposition ; Nickel compounds
  8. Source: Sensors and Actuators, A: Physical ; Volume 121, Issue 2 , 2005 , Pages 543-548 ; 09244247 (ISSN)
  9. URL: https://www.sciencedirect.com/science/article/pii/S0924424705002384?via%3Dihub