Nano Thermites!

[scarletmanuka]

I just came accross this site: http://www.technanogy.net/nanoaluminum_powders/index.htm which produces nano aluminium powders which are so small that they do not reflect light. Surely this would be a good alternative to german dark if one could get their hands on it. Infact, there are free samples in the ordering section. The only downside is the high oxy content.

[Blackhawk]

Forget nano thermites, nano flash powders. I would think though that something that fine may perhaps slow the burnrate down as the Al powder would be very dense and would not mix well with chunky oxidisers. If you did get it to mix though it would probably separate out with very little vibration/movement.

[scarletmanuka]

Well then Blackhawk, check out the part of the site that deals with nano-oxidisers. I imagine the CuO with 30m squared of surface area per gram would probably be pretty impressive when mixed with the Al.

[Blackhawk]

Yes, I have sent off my carefully worded piece of social engineering artwork in the hopes of getting a small sample bag to test it's usefulness. If you want to know what I said email me, but I can say there are some advantages to being a seniour student doing Chemisty for his HSC, especially the topic 'Industrial Chemistry' which involves investigating industrial manufacturing processes. This of course will only get me the 'Student scientific curiosity sample pack' they would get suspicious if I tried to buy a few Kg off them to 'Learn', so more work would have to be put in if it is feasible (cost effective). I would think if would be quite expensive though, probably only useful for very specialised aplications or as a cool gimic. (You call that dark Al, mines so fine it dosn't refract bloody light!)

[gliper]

"Forget nano thermites, nano flash powders. I would think though that something that fine may perhaps slow the burnrate down as the Al powder would be very dense and would not mix well with chunky oxidisers. If you did get it to mix though it would probably separate out with very little vibration/movement."---Blackhawk, Lab Assistant


Up to now everything Ive read says smaller = faster burn, because smaller particals have more surface aria to react imedietaly and they heat up faster. If mixing is a problem make a castable plaster insidiary CaSO4 + Al + H2O and bake untill the water is gone. Now that Al and oxidiser are conected you can grind it into a fine powder or what ever.

[Blackhawk]

Smaller burns faster to a point, fine granular BP will burn faster than well setled meal powder as the surface area is much greater (the meal packs which stops flame propagation to all surfaces), I'm affraid that the same may happen to the nano-Al unless it was suspended in a binder or somehow made to coat oxidiser particles.

[scarletmanuka]

I just got accepted to a Chem Eng/Analytical Chem double degree, and my best friend got accepted to Nanotech, I might just have a chance at a free sample... Anyone got any ideas as what I would be using it for?

[Crazy Swede]

Blackhawk,
The finer the particle, the greater the intimacy between the reactants! Why would that slow down a reaction? Everything made with nano-size metal fuels will burn/explode extremely fast!

I believe nano Al powders still are too expensive to be considered as anything but a novelty.

[Blackhawk]

Crazy Swede, I agree that would work to a point (unless the two powders had a large density differance) but unless you also have nano oxidiser particles you would not get a very good mix I would think, it would act like water running through gravel and the nano powder would quickly separate out in a dry mix.

[Bert]

High performance flash mixes use carefully chosen particle size and electrostatic properties to keep an optimum distribution and geometry of oxidizer/fuel.

[crackedchemist]

What about an aditive to your normal mix? As in you mix 50/50 aluminum/nano and then add that by weight to whatever mix you have. You might get the benefits of both the sizes. Or is this extremely stupid of me to think this?

[atlas#11]

For my flash I used to use sand paper and slowly grind the fibers out of ordinary printer paper and shake the flash in to it. It makes for great flame propogation but geting the flash to stick to the fibers was a bitch I got them damp in a baggie with a drop or two of water for about three days or so so it has adequeat time to evaporate and get evenly distributed. It would be benificial to use finely ground nitro cellulose for an energetic "suspender". Any way, I would like to see the effect of this nano powder.

[Bert]

This article mentions the experimental use of nano scale Al powders in priming mixtures:
Green explosives: Collateral damage (http://www.nature.com/cgi-taf/DynaPage.taf?file=/nature/journal/v427/n6975/full/427580a_fs.html)

It also ends with this quote:
Working to develop new explosives can be dangerous. "If you make one mistake it can be your last," says Klapötke. Three years ago, one researcher in his lab lost the top halves of two fingers in an explosion. "But he is still working in the field," says Klapötke.

Labs such as his can ill afford to lose staff, due to problems with recruitment. Klapötke admits that military links are off-putting for many students. And the pool of recruits is narrowed still further by his decision only to accept students from NATO countries for security reasons. Klapötke understands why some young chemists shy away from military research, but argues that his work is necessary. "We need defence, so we have to train people," he says. "But we don't want to kill them and pollute the environment."



Sounds like some of you all should be able to find work in the field, eh?