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Mr. Wizard
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| Quote: | Originally posted by cumbustion
Would Al foil ground up in a coffee grinder be fine enough for thermite? |
Strictly speaking ,yes. Quite large particles will work, but they become increasingly more difficult to ignite. When your materials get to the size of
rice grains you need an acetylene torch (or an equivalent) to make a molten pool of reacting components, then the reaction will proceed in a slow
manner if the material can fall into the molten reaction zone. This is a good thing if you are trying to form a casting or get a large piece of metal.
The finely ground material is easier to ignite, reacts more quickly, and has less time for the waste slag and metal to separate. A good analogy
would be burning charcoal. A large chunk will ignite with sufficient heat, burn slowly and do safe, useful work. A fine powder, mixed with oxidizers,
will burn quickly, and does a different sort of work.
A mistake I made was to use such small quantities of slow reacting thermite that I didn't get results. Using a 5cc pile didn't work with the
material I was using, but making a 200 cc pile and starting with a torch achieved a very strong , but slow reaction.
I would try to keep both component's particle sizes about equal.
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halogen
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Osmium tetraoxide/aluminum thermite. Is that possible?
F. de Lalande and M. Prud'homme showed that a mixture of boric oxide and sodium chloride is decomposed in a stream of dry air or oxygen at a red heat
with the evolution of chlorine.
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12AX7
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Liquid right? Or at least low melting point. It would probably react on contact.
Which reminds me, how about Mn2O7? 
Tim
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neutrino
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I doubt it would work. OsO<sub>4</sub> has a very low boiling point (130*C), so it would boil off before it could react. Imagine
Al/H<sub>2</sub>O thermite...
[Edited on 10-12-2005 by neutrino]
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PHILOU Zrealone
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To me everything is possible...everything depends on the speed of reaction...remember that the highly volatile halocarbons do stil react explosively
with Al powder or with alkaline metals (initiation by shok or heat)...
So the fact OsO4 is a volatile compound wouldn't be a sufficient reason to say it shouldn't work...
Mn2O7 may on react on contact with Al like it would with any reducer/fuel ...and as Mn2O7 is sensitive explosive by itself...
 
PH Z (PHILOU Zrealone)
"Physic is all what never works; Chemistry is all what stinks and explodes!"-"Life that deadly disease, sexually transmitted."(W.Allen)
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Mr. Wizard
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Be aware the oxide of this metal is very toxic, volatile, and expensive. 
http://www.chm.bris.ac.uk/motm/oso4/oso4h.htm
I think the 'thermit' reaction might take place under very high pressures, over the melting temperature of Al , as in an explosion. The analogy of H2O
and Al thermit was a good one.
[Edited on 14-12-2005 by Mr. Wizard]
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chemoleo
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Yes, it comes at around 120$ per gram, and purchases of more than a gram are highly restricted, due to its potential use as a chemical weapon.
Laboratories normally use highly dilute solutions.
http://cns.miis.edu/pubs/week/040413.htm
Now, please, can we go back to somewhat more realistic options? Or are we going to discuss the use of plutonium oxide for thermites, for the next 10
posts?
Never Stop to Begin, and Never Begin to Stop...
Tolerance is good. But not with the intolerant! (Wilhelm Busch)
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halogen
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Now that's an idea...
Wasn't an I2O5 mixture discussed earlier, or was it the roguesci thread?
[Edited on 16-12-2005 by halogen]
F. de Lalande and M. Prud'homme showed that a mixture of boric oxide and sodium chloride is decomposed in a stream of dry air or oxygen at a red heat
with the evolution of chlorine.
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PHILOU Zrealone
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| Quote: | Originally posted by Mr. Wizard
I think the 'thermit' reaction might take place under very high pressures, over the melting temperature of Al , as in an explosion. The analogy of H2O
and Al thermit was a good one.
[Edited on 14-12-2005 by Mr. Wizard] |
Again the only need for the reaction to occure is that the speed of reaction is superior to the heating and boiling of...as a mather of fact...there
is a chance Al burns in a vapourised fluid...
I the example I gave Al powder /CCl4 is a detonable mix and CCl4 is volatile fluid...Maybe sore rare combination are even shok sensitive/flame
sensitive...
In the case of OsO4 eveything depends on the capacity of OsO4 to give its oxygen and of the heat of reaction..Delta Gr and Delta Hr...
| Quote: | Originally posted by halogen
Now that's an idea...
Wasn't an I2O5 mixture discussed earlier, or was it the roguesci thread?
[Edited on 16-12-2005 by halogen] |
Despite the strong analogy between the type of reaction:
Oxygen transfer between an oxydiser and a reducing metal...
10 Al(s) + 3 I2O5(s) --> 5 Al2O3(s) + 3 I2(g)
It would no more be a thermite in the proper sense of the term...since I2O5 is a non metal oxyde...
So maybe start a new tread  otherwise this will turn into a mess...were flash
compositions will be mixed up with real thermites...
[Edited on 16-12-2005 by PHILOU Zrealone]
PH Z (PHILOU Zrealone)
"Physic is all what never works; Chemistry is all what stinks and explodes!"-"Life that deadly disease, sexually transmitted."(W.Allen)
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kABOOM!
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I'm ready in the mood to try the CuO/Al in combination with the KMnO4 flash powder in some kind of confinded environment for a reactive target. This
should be real fun on the firing range. Will take photo's and high quality video of the event. Stay tuned!
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Chris The Great
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| Quote: | Originally posted by chemoleo
Now, please, can we go back to somewhat more realistic options? Or are we going to discuss the use of plutonium oxide for thermites, for the next 10
posts? |
Considering the extreme reactivity and flammability of plutonium, I think it would potentially replace Al as the fuel. Pu is a very strong reducing
agent....
That is also why plutonium oxide would make a poorer oxygen carrier in thermite.
For unrealistic thermites I would go with gold (III) oxide and Al.
How about peroxide compounds like zinc peroxide? Or maybe copper peroxide (dun't know how to make it) CuO2 which would be substantially more
energetic than the CuO mixture.
I think the synthesis might be as simple as H2O2 + Cu(OH)2 -> CuO2 + 2H2O
But I am not sure (that method works to make zinc peroxide).
[Edited on 29-12-2005 by Chris The Great]
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kABOOM!
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...maybe Barium Peroxide/Magnesium --- Aluminum could be a substitue as well... thats a recepy for impact incendary 50 calibre bullets after they got
rid of white phosphorus in WWII due to its instability. Just found out about that one...just sharing.
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neutrino
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Would this produce molten barium metal or just a bunch of oxide? If it is the latter, wouldn't this be more accurately classified as a flash powder
than a thermite?
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kABOOM!
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Barium Peroxide /Al is certianly an incendary mixture...its not thermite thats for sure. The larger 150mm howitzer shells used a thermite filler with
a percussion fuse and combustable core w/ small HE charge for dispersal.
play safe, play hard...get your lumps...pick yourself up and try again. It will only make you stronger.
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12AX7
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BaO<SUB>(2)</SUB> + Al > Al2O3 + Ba (unbalanced)
The caveat is the Ba has to be driven off by heat (yellow hot) and sublimated under vacuum. The reaction proceeds due to Al2O3's stability and Ba's
(or any other alkaline earth, sans beryllium, for that matter) relatively low boiling point. Not exactly exothermic, though the peroxide will give
some initial energy at least.
Ag2O2 would be pretty skookum.
Tim
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kABOOM!
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I'll see what else I can dig up on military tracer/incendary compositions. Heres another: KClO3/Mg/SrCl2 (red tracer)
KClO3/BaCl2/Mg (green chinese/Russian tracer)
play safe, play hard...get your lumps...pick yourself up and try again. It will only make you stronger.
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crankyperson
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hellou,
i succesfully prepared chrome and silicium.
chrome is prepared out of Cr2O3 and Al, and silicium out of SiO2 and Al.
I started the reaction with some Mg-powder and a mixture out of KMnO4 and Glycerol..
there are some pics in a german chemnistry forum.if you want to see them,i can put them in....
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AngelEyes
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From NewScientist.com...
Exploding ink
A very unusual ink-jet printer cartridge, containing explosive ink, has been patented by Qinetiq, the commercial spin-off of the British Ministry of
Defence.
The ink is a mixture of very fine aluminium particles, each 1 micrometre in diameter, particles of copper oxide 5 micrometres wide, epoxy varnish and
alcohol. The ink is stable in liquid form, making it safe to print onto conventional paper, but forms an explosive fuse once dry.
An engineer can easily sketch out a printable fuse using computer imaging software, modifying the delay in milliseconds by changing the length,
thickness and pattern of the line on the paper.
The ink can then be printed between a small strip of metal and a larger patch of explosive ink. Feeding a current through the metal strip makes it hot
enough to ignite the fuse, which burns until it reaches the explosive patch. This explosion can then trigger the detonation of a much larger amount of
explosives.
Qinetiq suggests printed fuses could be used for precisely controlling fireworks, triggering vehicle air bags or for conventional munitions. Ganging
hundreds or thousands of fuses together could even make a miniature rocket engine capable of precisely adjusting the orbital position of a spacecraft,
the company says.
Read the exploding ink patent in full here. http://tinyurl.com/d6sow
\'Silk and satin, leather and lace...black panties with an Angel\'s face\'
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bomberman41688
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That sounds very interesting. I'd like to try that.
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Quince
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I don't see how you can DIY powder this fine.
\"One of the surest signs of Conrad\'s genius is that women dislike his books.\" --George Orwell
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chemoleo
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Crankyperson, I'd like to hear more details on your reaction with SiO2/Al.
I was never able to do it with this straight mixture, regardless the type of SiO2, even fine dried powder wouldnt do it. I did succeed with sulphur
however.
How did you do it without?
Do post the link btw.
Never Stop to Begin, and Never Begin to Stop...
Tolerance is good. But not with the intolerant! (Wilhelm Busch)
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Microtek
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I have used a blender to mill an alcoholic slurry of Al foil. The resulting dispersion of particle sizes were then sorted by various sedimentation and
filtering techniques in the wet state. The finest fraction was collected in a filter and examined in an optical microscope and was found to mainly
contain particles in the 1-5 micron range.
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Endo
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| Quote: | Originally posted by chemoleo
Crankyperson, I'd like to hear more details on your reaction with SiO2/Al.
I was never able to do it with this straight mixture, regardless the type of SiO2, even fine dried powder wouldnt do it. I did succeed with sulphur
however.
How did you do it without?
Do post the link btw. |
I once reacted ground quartz with magnesium dust in a test tube, On strong heating it started and the exothermic reaction was hot enough to deform my
test tube.
One interesting side note is it makes a Silicon-magnesium complex that yeilds Silane gas (Bubbles flash when they hit air) if you dump the end product
into HCl.
Not sure if aluminum would do the job...
[Edited on 14-3-2006 by Endo]
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kABOOM!
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Cu/Al BIG TARGET EXPLOSION VIDEO
yep, I'm back at it again. This time I tried to shoot a rather large exploding target using my .223 NATO - Ruger Mini-14. Enjoy the video... PS, it is
in MP4 format.
[Edited on 22-4-2006 by kABOOM!]
Attachment: MVI_1431.MP4 (876kB)
This file has been downloaded 1835 times
play safe, play hard...get your lumps...pick yourself up and try again. It will only make you stronger.
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12AX7
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Nice.
Ballpark or exact weight of charge?
Tim
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