ferrofluids in action

[Jon]

Thanks PJs for the tip on ferromagnetic fluids; fascinating stuff, hope to have more on it in the future.

Ferrofluids are fluids that can be controlled with a magnetic field; essentially composed of magnetic nanoparticles that are dispersed in a liquid. Invented in 1963 by a NASA scientist Steve Papell, as a fuel that could be drawn to a pump in zero gravity.



Applications are promising, but limited. Liquid seals seem to be the most common, but ferrofluids can also be used for friction reduction, propulsion, medical drug targeting, and optics.

Stirling motor builders have used them to seal pistons:

People are DIYing them from vegetable oil and printer toner.

Of course life would not be complete without a Kickstarter for a ferrofluid lava lamp, uh, I mean "motion lamp of the future". I thought this one was a parody, but it's actually a real, successfully funded Kickstarter:

[PJs]

Thanks Jon for posting this. I find the gear in the gif fascinating with a worm to conical then a spur...what would that drive? And the way the fluid rides the crest of the worm and gears to a sphere at the top says a lot about the way the fluid works along the flux lines. Most of the general info out there is about the sensation and eye candy of it for demonstrations. I've seen and watched a bunch of the DIY Ferrofluid stuff but the commercially made fluid is a vast difference in physical properties. Also DIYing it is a bit dangerous for the home DIY IMHO, and very messy if not careful. The manufacturing/engineering/ChemE side of it is really being driven by the applications now, so there are vast array of base fluids and viscosity's as well as grain size and the surfactants used but it's still pretty pricey in my book. As application picks up momentum it'll come down as it has already, like most things. Applications are huge from speakers, MRI, heat transfer, bearings, seals, dampening and even propulsion etc. Space Propulsion really hasn't gotten off the ground as far as I know but maybe soon with these micro satellites.

To think it's been around for a half century and only now (last decade+) being used in commercial applications is a bit of a mystery. I didn't hear about it until the mid to late 70's and then later saw some stuff in trade magazines. Wiki is a good start but a tip of the iceberg to what's gone and going on out there...like carbon nano tech and 3D chip tech. Non magnetic mechanical pumping this fluid is a field I am interested in.

Thanks again for putting these up for the Forum. Looking forward to what every you find in the future. ~PJ

[rendoman]

Like the ferrofluid animation!