Ferrofluid as Core Material

[Louis Porter]

Can anyone predict how ferrofluid would function as an electromagnetic
core material for RF? The point would be that, unlike solid ferrite,
it would closely immerse the entire coil. Not sure about its
properties in this regard though, and the stuff is a bit expensive for
an uneducated guess.

Louis Porter

 

[Tim Williams]

They should make ferromayo, that stuff lasts forever

Tim

 

[Les Cargill]

I got a sample of ferrofluid years ago in a sealed glass tube and the
material in solution congealed. I'm not sure it is very stable.

I would think it's an emulsion or suspension more
than a solution. <Googles....> they are colloids,
and colloids are not stable for long.

 

[tm]

They should make ferromayo, that stuff lasts forever

Tim

--

Isn't that what jap screws are made of?

 

[Les Cargill]

They should make ferromayo, that stuff lasts forever

Tim

I expect ferropeanutbutter *would* last forever!

 

[Dirk Bruere at NeoPax]

The wiki goes into stability of the fluid. I hadn't realized they use
the fluid in disk drives.I know it is used in high fidelity speakers.

You could always make up your own eg grind up ferrite and mix it into
molten wax or somesuch before casting it.

 

[Kevin McMurtrie]

Can anyone predict how ferrofluid would function as an electromagnetic
core material for RF? The point would be that, unlike solid ferrite,
it would closely immerse the entire coil. Not sure about its
properties in this regard though, and the stuff is a bit expensive for
an uneducated guess.

Louis Porter

Aren't some inductors already using ferrous epoxy? I seem to recall
cracking open some surface mount chokes and seeing no gaps around the
wires.

Ferrofluid would be erratic because the particles can move around by
gravity and low frequency fields, at a speed that would be temperature
dependent.

 

[Clifford Heath]

You could always make up your own eg grind up ferrite and mix it into
molten wax or somesuch before casting it.

I believe the Internet wisdom for making your own ferrofluid is
to precipitate iron oxide from FeCl3 solution, in stearic acid.
You get nice small particles that way...

 

[Dirk Bruere at NeoPax]

I believe the Internet wisdom for making your own ferrofluid is
to precipitate iron oxide from FeCl3 solution, in stearic acid.
You get nice small particles that way...

But do you want small particles?