| Topic: |
Science > Physics |
| User: |
"" |
| Date: |
01 Sep 2006 05:06:59 PM |
| Object: |
turning liquid ammonia into a ferrofluid |
Can a stable (i.e. with low hysteresis) ferrofluid be created with
liquid ammonia (pressurized at room temperature) as its carrier fluid?
If so, at what approximate concentration of ferromagnetic particles
does the ammonia reach full saturation? Will magnetic particles remain
Brownianly dispersed in a strong magnetic field over a long period of
time and can surfactants stay intact during long term contact with
ammonia?
I couldn't find this kind of info with Google so it might not be easy
stuff to answer, but if anyone has an idea where I might find more
relevant information on this, I'd love to hear that too.
Thanks,
Ruben
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| User: "Uncle Al" |
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| Title: Re: turning liquid ammonia into a ferrofluid |
05 Sep 2006 12:43:37 PM |
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wrote:
Can a stable (i.e. with low hysteresis) ferrofluid be created with
liquid ammonia (pressurized at room temperature) as its carrier fluid?
If so, at what approximate concentration of ferromagnetic particles
does the ammonia reach full saturation? Will magnetic particles remain
Brownianly dispersed in a strong magnetic field over a long period of
time and can surfactants stay intact during long term contact with
ammonia?
I couldn't find this kind of info with Google so it might not be easy
stuff to answer, but if anyone has an idea where I might find more
relevant information on this, I'd love to hear that too.
Art is the concept, craft is its reduction to practice. One suspects
you are a deficient craftsman.
Start with the usual aqueous ferrofluid prep: ball mill magnetite,
add surface oleic acid to keep things separate, add to your alkaline
suspension medium. Or precipitate ferrite from solution, use
tetraalkylammonium to keep things separate, dry, add to suspension
medium (J. Chem. Ed. has a lovely aqueous ferrofluid prep).
You have at least three problems ("issues" or "challenges" my *****) in
liquid ammonia,
1) relative densities,
2) preventing colloid clumping,
3) oxidation of the susceptor
1) As liquid ammonina approaches its triple point its denesity
drops toward that of the gas phase. Magnetic stuff tends to be dense
and dumps out of the tenuous medium.
2) The colloidal particles must be charged by adsorption of a
charged separation agent to prevent clumping - especially when
compacted in a magnetic field. What will remain chemisorbed or
adsorbed in liquid ammonia?
3) Ammonia is a powerful transition metal complexing agent. It
promotes solubilization. It promotes air oxidation of low and
mixed-valence oxidation states, then with dissolution.
--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
http://www.mazepath.com/uncleal/qz3.pdf
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| User: "Eric Gisse" |
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| Title: Re: turning liquid ammonia into a ferrofluid |
01 Sep 2006 07:06:14 PM |
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wrote:
Can a stable (i.e. with low hysteresis) ferrofluid be created with
liquid ammonia (pressurized at room temperature) as its carrier fluid?
If so, at what approximate concentration of ferromagnetic particles
does the ammonia reach full saturation? Will magnetic particles remain
Brownianly dispersed in a strong magnetic field over a long period of
time and can surfactants stay intact during long term contact with
ammonia?
I couldn't find this kind of info with Google so it might not be easy
stuff to answer, but if anyone has an idea where I might find more
relevant information on this, I'd love to hear that too.
Thanks,
Ruben
I have no idea how to answer this but....why liquid ammonia?
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| User: "" |
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| Title: Re: turning liquid ammonia into a ferrofluid |
01 Sep 2006 08:17:46 PM |
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I have no idea how to answer this but....why liquid ammonia?
Among my requirements is having a carrier fluid with a boiling point
(*) close to room temperature and high specific heat capacity. Ammonia
seems suitable. However... now that you made me think about it some
more, a light type of hydrocarbon might be a good alternative, if that
makes things any easier(?)
(*) Supposedly I have a part of the carrier liquid evaporated, then I
need the magnetic patricles to stay suspended in the remaining
non-evaporated carrier. The resulting increase in concentration is why
asked that question about saturation...
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| User: "Eric Gisse" |
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| Title: Re: turning liquid ammonia into a ferrofluid |
02 Sep 2006 01:04:36 AM |
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wrote:
I have no idea how to answer this but....why liquid ammonia?
Among my requirements is having a carrier fluid with a boiling point
(*) close to room temperature and high specific heat capacity. Ammonia
seems suitable. However... now that you made me think about it some
more, a light type of hydrocarbon might be a good alternative, if that
makes things any easier(?)
(*) Supposedly I have a part of the carrier liquid evaporated, then I
need the magnetic patricles to stay suspended in the remaining
non-evaporated carrier. The resulting increase in concentration is why
asked that question about saturation...
I'm the wrooooooong guy to ask about this. I think the class of
substances are neat, though.
Wikipedia [god help me] gave this as a reference:
Ferrohydrodynamics (1985), Ronald. E. Rosensweig.
You should dig through that to see if you could get some ideas, or see
if that reference contains other references that would help. It is a
start.
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