Sciencemadness Discussion Board

Group Buy Nano Al Powder

malford - 22-6-2013 at 11:14

http://www.us-nano.com/inc/sdetail/467

I see no statement anywhere that only institutions can make purchase. If I am wrong, please correct.

This is spherical aluminum powder less than one-half of one-tenth of a micron, i.e. 40 nanometers. They sell it down to 18nm but I'm afraid the oxide layer would have replaced too much of the Al.

I would like to purchase 100g for $368 if a few others are interested. I would ship it anywhere in the US for $6 and international would vary, so message me.

The price per gram comes to $3.68. I'm OK with shipping any amount you're interested in.

P.S. I did this with another chemical unintentionally and it worked out well for several people, so why not try it with this! I just want to experiment with small amounts of flash powders and ANNMAl using nano Al so I don't need 100g.

plante1999 - 22-6-2013 at 11:20

Group purchase party?

I believe this one will be harder to find buyer, but who knows.

woelen - 22-6-2013 at 12:06

Using such an expensive high-tech product for something like flash-powder??? Seems like a total waste to me. This stuff is intended to be used in very special applications.

I also read that this material should not be exposed to air. Air will make the nano-particles lump together and spoils the material. I doubt that this material will give any performance increase in flash powder, when compared to stuff like german dark. I am afraid that you cannot handle this material in a normal home lab.

Fantasma4500 - 22-6-2013 at 12:07

i would consider it if i was near USA but im not, also it wouldnt be very cheap

why not try to make nano magnalium and then cover it with charcoal??
like 1 month of ballmilling with good media
as its known magnalium is very easy to break into smaller particles, compared to magnesium or aluminium..
anyways price would come down to 3.68 per gram, still some price

what was you expecting with the ANNMAl anyways..?? for secondaries it wouldnt be very smart to use such exotic meshes.. i would see reason in KMnO4 Al flash tho

malford - 22-6-2013 at 13:40

woelen,

Correct me if this statement is wrong: in pyrotechnics, the size of the flakes or spheres of Al greatly affect its performance. As such, I do not believe that the current standard of around 2-3 microns was created by experimentation with both larger and smaller size particles -- only larger particles which exhibited lesser performance. Smaller particles have not been experimented with only because they are nearly unavailable. Why should we assume that smaller than 2-3 microns will not exhibit a continuing trend of increased performance?

Antiswat,

Can you explain how it is not possible smaller Al particles to affect the sensitivity or velocity of detonation of ANNMAl? That seems to be what you are saying.

Dr.Bob - 22-6-2013 at 13:58

Pyros have been playing with Al powder for years, and figured out many years ago how to get the best mix of safety, performance, and practical usage. I am quite sure that many have tried smaller particles, and they are not that much better. You could do a little research in the energetic materials area and find that. There is such a thing as diminishing return, and while smaller particles do speed up the reaction, there are many other factors that make going smaller still eventually not return any real improvement due to physical limits on burn rate. And you do need to be careful, as some fine Al powders are indeed pyrophoric, and likely to create an unstable flask powder.

So while particle size matters, it cannot change the thermodynamics of burning Al, there is a limit to the burn speed/velocity. And I think the point was that too small a particle WOULD change the sensitivity, thus making it much less safe to work with, especially in a home lab. Lastly, $368 / 100 gram is an insanely high price for Al powder for pyro uses. No one should be spending that much for Al powder, when it normally sells for $20-40/pound or $4-$8/100g.

malford - 22-6-2013 at 14:16

Dr. Bob,

Thanks for your input, but I believe you misunderstand my intentions. I experiment and, thusly, learn. I am not aiming to simply create small explosions for the satisfaction of doing so. I am aiming to research through hypothesis and experimentation. The $368 is not for aluminum, it is for the specific particle size and the sequent experimentation that is otherwise not possible.

Even if the decreased size nets a 10% increase in performance, that information was worth the research cost and time.

The point of diminishing return of which you speak I assume, though you did not specifically mention it, is related to the depth of the oxide layer. If the particle size is the same as the depth of the oxide layer, you have no Al. I do not yet know what the depth of the oxide layer is for the aforementioned powder, but would confirm that it is shallow enough to provide a considerable amount of Al before purchase.

On the other hand, your point of diminishing return may simply be about physics and the maximum speed of the reaction. I'm sure, as you are, that there is such a point, however, who knows exactly where that is? Current pyro grade aluminum might be 10, 20, 30 percent short of its theoretical maximum. If this is the case, flash powder with sufficient confinement could most likely be used to detonate secondaries like ANNMAl, ETN, MHN, etc. If this is in face the case, the $368 would be negligible.

I greatly appreciate the warning of increased sensitivity and decreased stability.

AndersHoveland - 22-6-2013 at 15:46

For explosive compositions, nano-Al powder is important because regular pyrotechnic grade Al powder cannot react fast enough. Nano-powder is typically only used in high performance explosives with higher detonation velocities. Adding regular Al powder to RDX, for example, would not improve performance at all.

But if it is just ammonium nitrate based compositions, no need to waste expensive nano-powder, and besides, the high surface area of nano-Al powder would also lead to chemical compatibility problems in storage, since moist AN can be rather corrosive.

malford - 22-6-2013 at 17:44

Anders,

If nano Al is of no use for high VoD compositions like RDX and is of no use for lower VoD compositions using AN, what are the explosive compositions of which you speak for which nano-Al is important? Would this be flashpowder-like compositions?

woelen - 23-6-2013 at 04:34

If you try experiments with the nano-powder, then the other components in the mix also should have such small particle size. If these are still much larger, then the pockets of air between the larger compounds simply will be filled up with nano particles.

Think of having a box full of oranges and peas. Even if the oranges are tightly packed, there is still quite some space. This space can be filled up with peas. But the total contact area is not the contact area of the peas, it only is the contact area where the peas are next to an orange. A similar effect will occur in a pyrotechnic mix with nano-sized fuel particles and much larger sized oxidizer particles.

Fantasma4500 - 23-6-2013 at 07:47

Quote: Originally posted by malford  
woelen,

Antiswat,

Can you explain how it is not possible smaller Al particles to affect the sensitivity or velocity of detonation of ANNMAl? That seems to be what you are saying.


it surely does, but for ammonal types i think its a sure waste to use it as you need to initiate it by a great energy anyways
like.. what do you expect, something different than with 400 mesh al or 1-3µm?
also how would you see it?

GD Al is more than enough for ammonal

also about the use of nano al..

http://www.youtube.com/watch?v=-b7siH1Ausc

it is being experimented with, and this is what you can use ultra fine aluminium dust for.. (:

Dornier335 might be interested in talking about superfine metal powders, hes got a youtube channel also where he shows what it can mean to a composition, hes on SM aswell so send him a message.. you might be able to make small amounts easier than you think

malford - 23-6-2013 at 13:12

woelen,

Let us have a container full of oranges and apples that are mixed thoroughly. Visualize the area in which the apples touch the oranges.

Now let us replace the apples with your peas. There will be much more area in which peas are touching oranges. The peas will coat the oranges.

Antiswat,

I'm mainly interested in using it for flashpowder and initiating compositions. Cool video. Many years ago I was highly interested in rocketry.

malford - 30-6-2013 at 20:22

As an update in case anyone is interested in this group buy, documents such as this are widespread and reflect the extremely energetic potential of nano particles.

http://infohouse.p2ric.org/ref/34/33115.pdf

woelen - 30-6-2013 at 22:40

Quote: Originally posted by malford  
woelen,

Let us have a container full of oranges and apples that are mixed thoroughly. Visualize the area in which the apples touch the oranges.

Now let us replace the apples with your peas. There will be much more area in which peas are touching oranges. The peas will coat the oranges.
Yes, there will be more contact area, but still, most of the Al-particles will only touch other Al-particles. Although there may be more contact area, the oxidizer needs to come from 'far' (on the scale of the nano particles) for most of the time. If you really want to benefit from the small size, then you need to have nano-sized oxidizer particles as well.

What _might_ be interesting is melting the oxidizer and mixing the Al-particles into that molten oxidizer. This, however, seems like a very dangerous operation to me, especially if the melting temperature of the oxidizer is several hundreds of degrees C. Maybe you get interesting results if you take a highly water soluble oxidizer (e.g. NaClO4, mixed with a small amount of Na2Cr2O7 in order to passivate the Al-particles and protect them against the water) and mix a saturated solution of this with the Al-particles and then allow the mix to dry.

[Edited on 1-7-13 by woelen]