28 September 2001 Applications of shape memory alloys: advantages, disadvantages, and limitations
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Proceedings Volume 4557, Micromachining and Microfabrication Process Technology VII; (2001) https://doi.org/10.1117/12.442964
Event: Micromachining and Microfabrication, 2001, San Francisco, CA, United States
Titanium-nickel (TiNi) based shape memory alloys (SMAs) are used in a wide range of applications. They are especially practical as thin film actuators because of the large work output per unit of actuator mass and ability for rapid thermal cycling due to large surface to volume ratio. Sputter deposited thin TiNi film has been developed for use in miniature actuators for microvalves, microrelays, optical switches and also for building small implantable medical devices. Chemical composition of the deposited SMA must be held within close limits and for the film to have shape memory properties a crystallization anneal is required. To avoid flaws in film quality the surface on which SMA is deposited has to meet certain criteria. Basic MEMS processes (photolithography and chemical etching) are used for device fabrication. Although TiNi is resistant to most chemicals, some acids used in MEMS can damage it. Thus, selection of processes and reagents compatible with TiNi requires care and experimentation. This paper discusses some applications of SMA thin films along with experience gained in bringing device s to production readiness. It illustrates simple design rules for incorporating shape memory microactuators in MEMS devices and describes some of the pitfalls to be avoided.
© (2001) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
A. David Johnson, A. David Johnson, Valery Martynov, Valery Martynov, Vikas Gupta, Vikas Gupta, } "Applications of shape memory alloys: advantages, disadvantages, and limitations", Proc. SPIE 4557, Micromachining and Microfabrication Process Technology VII, (28 September 2001); doi: 10.1117/12.442964; https://doi.org/10.1117/12.442964

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