a small wire that changes shape with external magnetic field

Discussion in 'General Electronics Chat' started by James Kr Ma, Dec 20, 2017.

  1. James Kr Ma

    Thread Starter New Member

    Dec 20, 2017
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    I have used Nitinol as a shape memory material for a small experiment that requires change of shape ( curved to straight or small to longer) to be controlled. These materials change shape due to external temperature variation. Now I am looking for some materials that will change shape with applied electric or magnetic field. Is there anything practically usable? Heard about magnetic memory alloys. Can anyone help me to point me a micrometer length wire to change its length or shape upon external field variation?
     
  2. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    Welcome to AAC!
    Magneto-strictive materials change dimension in response to applied magnetic fields, but the effect is small.
    Piezo-electric materials change dimension in response to applied electric fields.
    A heating coil wound around a Nitinol wire would respond to the coil current.
     
  3. James Kr Ma

    Thread Starter New Member

    Dec 20, 2017
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    Thanks a lot!
    My material is of few micrometer length and looking for few bodylength change in length upon field activation.
    As my medium is water will have to see how these fields can get in. Another issue with Nitinol is timedelay. As i want high frequency changes will see some other ways.
     
  4. kubeek

    Expert

    Sep 20, 2005
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    I doubt you can get more than a few percent elongation from anything magnetostrictive or piezoelectric. How about a tiny MEMS solenoid?
     
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  5. James Kr Ma

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    Dec 20, 2017
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    Thanks for that. You mean i can change length of MEMS solenoid using current?
     
  6. kubeek

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    No. Solenoid is a movable core inside a coil, you don't change the size of the coil but pull in the core. Maybe there is a mems equivalent of that.
     
  7. KL7AJ

    AAC Fanatic!

    Nov 4, 2008
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    Actually, a plain coil of wire will "want" to unwind with the application of current. (Lenz's Law). It's a subtle effect at small current levels, but certainly measurable.
     
  8. ElectricSpidey

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    Dec 2, 2017
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    Look into what they use in reed relays.
     
  9. Externet

    AAC Fanatic!

    Nov 29, 2005
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    Any iron wire will react to a magnetic field.
     
  10. James Kr Ma

    Thread Starter New Member

    Dec 20, 2017
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    Oh ok...i will search for that...thanks
     
  11. James Kr Ma

    Thread Starter New Member

    Dec 20, 2017
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    :) yes...you are right...I want to change length/shape/rotate the wire placed inside water through the applied magnetic field from outside..
     
  12. kubeek

    Expert

    Sep 20, 2005
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    Something like a magnetic stirrer?
     
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