[TheIronHobo]

Hello Chemical Forums!

I am more of an electrical engineer so I feel very out of place here. Hopefully the chemical sciences take as fondly to me as I am perplexed by them. I was wondering what the best/most efficient procedure there is for producing magnetite at the diameter of 10nm or less at a hobbyist level? I seek to experiment with different concoctions of ferromagnetic substances but I need to bring down the size of the particles so I can prevent them from clumping together in the presence of a magnetic field. I've looked into planetary ball mills (horrifically expensive equipment) and producing tiny magnetite via a transmutation of PCB etchant/ferric chloride(fairly expensive chemicals and small yield). Is there a reliable source to buy bulk nanometer magnetite or a better hobbyist level process for creating it then the ones listed above?

Ball Mill
https://us.vwr.com/store/catalog/product.jsp?product_id=4784656
PCB etchant ferrofluid
http://chemistry.about.com/od/demonstrationsexperiments/ss/liquidmagnet.htm

Thanks for the *delete me*
-IronHobo

[Irlanur]

i can't REALLY help, but did you check this? https://en.wikipedia.org/wiki/Iron_oxide_nanoparticles, coprecipitation seems suitable...

second, do you actually know what size you need, or was it just a wild guess? 10nm or 100 might have quite different properties and might be easier/harder to produce...

[Intanjir]

This is not trivial at a hobbyist level.

Even if you acquire a powder with a suitable primary particle size you will still have to disperse it.
This requires more than simply stirring.
Normally ultrasonics or specialized high shear mixing are required to break up the secondary particles.
It is conceivable that a blender would work well enough after a few hours.

You can often make nanoparticles of metal oxides by very careful precipitation. The idea is to precipitate a sol and not a floc or gel.
Googling 'magnetite sol' immediately yields a number of papers.

Precipitation alone will likely not result in quite the right form of iron oxide. Even if the stoichiometry of oxygen to iron is correct the crystal structure may very well be the wrong one, or just too disordered. A heat treatment(annealing) can fix this. The papers all seem to anneal their precipitate under vacuum to avoid adding oxygen. This strikes me as a bit hard to do at a hobbyist level.

Ferric Chloride is probably going to be the cheapest precursor. If you don't care for the price/purity of commercial etchant then perhaps make your own. Its just iron and HCl.

Probably the largest problem with doing it yourself is estimating/verifying the size and dispersion of the particles you've made.