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Magnetic Fluids

Posted by ryuzaki0 on from the flux-capacitor dept.

Polo writes: "Remember those magnetic sculpture things you can buy at the mall where these small metal pieces stay in one shape. Imagine doing that with Ferrofluids. This is just too cool. Dan is the nerd's nerd." Well, can't get any higher praise that that, I suppose. :) I have a couple of neodymium magnets and yes, they are much fun. Never played with magnetic fluid though.

4 of 103 comments (clear)

  1. ferrofluids, magnetic clutches by sfbanutt · · Score: 4, Interesting

    Ferrofluids have been used in magnetic clutches. You have two plates facing each other with vanes on them. Put them in a ferrofluid tank. When the magnetic field is absent, either shaft will spin freely without effecting the other. Add a magnetic field and WHAM, the shafts are locked together. I seem to remember there being a problem getting a decent amount of shear strength though. There was an article on this in Scientific American a few years back in the Amateur Scientist column.

    --
    I've wrestled with reality for 35 years and I'm happy to say, I finally won out - Elwood P. Dowd
    1. Re:ferrofluids, magnetic clutches by Animats · · Score: 3, Interesting
      Magenetic clutches...

      Yes. The paper feed mechanisms in the big line printers of the mainframe era often used ferrofluid magnetic clutches and brakes. Because they can clutch and release far faster than mechanical clutches, they're used when precision control of intermittent motion is required. Ferrofluid clutches can take constant, repeated impact loads with almost no wear; the energy is dissipated in the fluid, rather than in surface friction. Very neat.

      That technology goes back to at least the early 1960s.

  2. Magnetic Fluids by Anonymous Coward · · Score: 4, Interesting

    Fluids influenced by magnets have been around for a while.

    One of the problems facing the space program in its earliest days was how to re-fire liquid fueled rockets in a weightless environment. If you think about it, just exactly how do you get the fluids in a tank half full of rocket fuel to take a position over and in the sump of the tank so the pumps can supply reliable measures of fuel and oxidizer to the engines combustion chamber.

    The innovative solution was to mix the fuel and oxidizer with a ferrous based additive so that a large magnet at the sump of the tank would draw the fuel and oxidizer to the sump. This isn't a magnetic fluid but it is one of the ingenious solutions to a myriad of engineering challenges facing our space program.

  3. Try an old hard drive magnet by Fantastic+Lad · · Score: 2, Interesting
    Crack open one of those 100 Mb hard drives (which any geek worth his salt must have lying around), and pull out the rare earth magnets. Those things whoop speaker magnets any day of the week! (They're actually kind of worrisome to handle.)


    -Fantastic Lad