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Ferromagnetic powder question!

  1. Nov 24, 2014 #1

    I am trying to understand a few properties of the ferromagnetic powder.

    I could not get the answers to these questions on the web, since any kind of phrasing i used, popped up search results that related to iron powder or ferromagnetic powder, which are manipulated and shape-shift using solid magnets.

    On the other hand, i am interested only in the ferromagnetic powder properties, in other words:

    1. Does the ferromagnetic powder have a magnetic field of its own, without a solid magnet being in its vicinity? If it does, what field strength should i expect? Would it be detectable?

    2. Will a simple non-magnetic metal (that is usually attracted to a solid magnet) be able to attract some ferromagnetic powder on it, if it is dipped in the powder, when there is no solid magnet in its vicinity?

    3. If i make a ferromagnetic liquid, by mixing it with some kind of paint (there are many videos that demo this on the web), will a non-magnetic metal of the kind mentioned above, attract that ferromagnetic paint to it?

    4. If the answer to the above questions is no (and also if the answer is yes), if i hold a magnet above the ferromagnetic liquid-paint and leave the magnet above that paint spot until it dries, will the dried paint spot then still not have a detectable magnetic field of its own?

    Any layman and simple scientific answers or links, coupled with pictures and videos, will be more than welcome!!

    As mentioned above, i could find only answers that relate to the effects taking place in the vicinity of solid magnets, which is not what i am asking about!

    Thanks a lot!
  2. jcsd
  3. Nov 24, 2014 #2


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    I'm confused. Isn't ferromagnetic powder essentially what recording tapes are made of? If so, then it does maintain it's own field once magnetized.
  4. Nov 24, 2014 #3
    Yeah Danger,
    I can safely say that your comment sounds reasonable!

    Anyway i am going to make some experiments. The problem is that i'd rather like to try to understand in advance from common knowledge (so to speak), if the effects are at a scale which is detectable at a distance of 0.5-2 cm with a Hall effect sensor DIY Arduino play around equipment or is much more physical contact (as in tapes), chemical engineering and sensitive electronics, involved in getting the ability to detect such a hypothetical paint. Or does such paint product already exist?
  5. Nov 24, 2014 #4


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    I'm afraid that anything involving electronics or math is beyond my understanding. I can say, though, from my career in the security business, that electrically conductive paint has existed for decades and is used instead of foil in some window-breakage sensor applications. In fact, one main reason is that it can be made as transparent as the glass that it's painted onto. I see no reason why ferromagnetic particles couldn't be used in place of strictly conductive ones.
  6. Dec 12, 2014 #5
    There are two varieties of magnetic particles, soft and hard. Soft materials become demagnetized when an applied field is removed. These materials are great for making inductors and transformers.

    Hard magnetic materials can be permanently magnetized by a sufficiently strong field. Magnets are made from these materials, including refrigerator magnets, which are made of bound particles :-)
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