Electrically Activated Shape Memory Ceramics

Technology #16618

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Inventors
Professor Christopher Schuh
Department of Materials Science and Engineering, MIT
External Link (schuh.mit.edu)
Alan Lai
Department of Materials Science and Engineering, MIT
Managed By
Christopher Noble
MIT Technology Licensing Officer - Clean and Renewable Energy
Patent Protection

Electrically Activated Shape Memory Ceramics

US Patent Pending

Electric field activation of shape memory ceramics

US Patent 9,548,678
Publications
Shape Memory and Superelastic Ceramics at Small Scales
Science, 27 Sep 2013: Vol. 341, Issue 6153, pp. 1505-1508

Applications

Applications for solid state electrically activated actuators with large strains include: micro-robotics, haptics-tactile interfaces, electronics-camera auto-focus mechanisms, micro and nano positioning, fuel injector actuation.

Problem Addressed

Previous actuators such as shape memory metals or piezoelectrics do not provide large mechanical displacements via direct electrical activation. This invention creates the possibility to actuate a phase transformation with a large mechanical displacement using an electric field.

Technology

This technology is based on the principle that for any phase transformation to occur there must exist a difference in an extensive variable between the two phases. These materials (e.g. ceria-doped zirconia) exhibit a change polarization between phases, which has not been demonstrated before. This allows the material to produce a mechanical displacement when subject to an electric field. The simplest implementation of this type of actuator would resemble a parallel plate capacitor with a layer of active ceramic material between to conductive electrodes.  Then a voltage could be applied across the material which would induce an electric field and cause the material to actuate. 

Advantages

  • Actuation due to an electric field
  • Improved cyclic properties