uses and applications of superfine magnetite

In my day Job, I have access to large amounts of superfine magnetite. This is basically magnetite that has been ground down to become smaller than 53Microns (1000 micron=1mm) . My boss will let me take a few kilo's home to run some experiments and I'm wondering if anyone has any ideas on things I could try that would be useful for the project.

My current major idea is to get some of the finer particles (<20 microns, which is easily seperated) and put a small amount of them in a powdering over some solder wire. Melt the solder while it is layed out flat while I pass a current through it so the magnetite melts into the solder. Hopefully all the particles will align their fields along the current line and then when the solder solidifies again the particles will all be aligned together. I would then have weakly magnetic coil which is both conductive, ductile and contains a weak, but constantly aligned magnetic field. Or possibly we could put this solder-magnetite mix into the solder extruder and lay it out for future designs where a block of solid magnetic material would be good(plus the magnetite might partially mitigate the problem of low viscocity we have. It wouldn't really form a strong field, but maybe strong enough for some applications.

I also have noted during my day to day work that when you apply a magnetic field to the fine magnetite when it is in water, it begins to act in a way somewhat similar to a ferro-fluid. I know the particles are in fact far too big for this, and they do settle out after a while, but does anyone have any ideas about what I can do with a ferro-fluid in future that would be useful for the project.

Interesting! How weakly magnetic is "weakly magnetic"? Several of us have been talking on and off of mixing magnetic media with epoxy to make permanent magnet stepper motor rotors.

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Seems that won't work, although this [www.energeticforum.com] thread has some interesting info on using it for motor cores.

-Geert

magnetite is the most magnetic natural mineral on earth according to wikipedia. I know that it will attach itself to almost anything with iron in it pretty much immediately. I'm being somewhat careful for now, but hopefully I'll have some photos to put up on the builders blog soon.

Any advice on the epoxy tests or types of epoxy you'd recommend. As well as a way to provide an orientation for the magnetite, since this would be more useful. I wrote a post ages ago about an extruder head that would turn of and on with a solinoid embedded into it.

Thanks for the other site. They are saying the problem with magnetite is that it tends to be a relateively weak magnet. I'm hoping that by orientating it, I can make a stronger field collectively, their instructions seem to be to just mix it with resin and let it set.

... look here: [forums.reprap.org]

Viktor

Hmmmm

I am certainly no expert on this. My understanding is that if you just mix it and let it set you will get some natural alignment.

Probably in little loops (N to S etc etc etc)

The loops should give you a week field.

Guess the question is if you try the same thing with a strong magnetic field present will you get it to align better. ie in little lines instead of loops.

The magnetic field you use may need to be fairly strong and set up so that it formed the final patterning you wanted.

I actualy dont know much about this, just freewheeling.

Cheers

aka47

PS Ferro fluid pastes may have useful application as support material. Thinking of the funny sculptures people make when piling up ball bearings on speaker magnets.

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It Also Can Be Used For Jewelery .