Sciencemadness Discussion Board
Not logged in [Login ]
Go To Bottom

Printable Version  
 Pages:  1  ..  6    8    10  ..  24
Author: Subject: Exotic thermites & analogs
kABOOM!
Harmless
*




Posts: 40
Registered: 19-12-2005
Location: Pacific side of Canada
Member Is Offline

Mood: No Mood

[*] posted on 21-4-2006 at 21:08


The video shows 1/2 lb of CuO/Al mix...by weight, hard packed into a large plastic ball.

[Edited on 22-4-2006 by kABOOM!]




play safe, play hard...get your lumps...pick yourself up and try again. It will only make you stronger.
View user's profile View All Posts By User
PHILOU Zrealone
International Hazard
*****




Posts: 2879
Registered: 20-5-2002
Location: Brussel
Member Is Offline

Mood: Bis-diazo-dinitro-hydroquinonic

[*] posted on 24-4-2006 at 06:39


Quote:
Originally posted by Microtek
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.


I dont think the use of an alcohol is a good idea when you get to very fine Al powder ... since a good deal of your Al might react to give alcoholate...unless your Al is somehow passivated by a resistant oxyd layer

Al + 3R-OH --> Al(O-R)3 + 3/2 H2

To my idea better use low bp and unreactive alcanes to allow separation...hexane, heptane, octane...




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)
View user's profile View All Posts By User
kABOOM!
Harmless
*




Posts: 40
Registered: 19-12-2005
Location: Pacific side of Canada
Member Is Offline

Mood: No Mood

[*] posted on 24-4-2006 at 23:22


I guess my next test should be with red lead & Aluminum...tested with a good ol' blast from a rifle. Anyone here made such a mixture? I'm guessing a similar mix was used in rail car crackers, and step on torpedos...right?



play safe, play hard...get your lumps...pick yourself up and try again. It will only make you stronger.
View user's profile View All Posts By User
PHILOU Zrealone
International Hazard
*****




Posts: 2879
Registered: 20-5-2002
Location: Brussel
Member Is Offline

Mood: Bis-diazo-dinitro-hydroquinonic

smile.gif posted on 25-4-2006 at 08:30


Be careful because PbO2 is a powerful oxydiser and...PB is easily molten and its boiling point is arround 1750°C so gaseous hot Pb might result...:D



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)
View user's profile View All Posts By User
Mr. Wizard
International Hazard
*****




Posts: 1040
Registered: 30-3-2003
Member Is Offline

Mood: No Mood

[*] posted on 25-4-2006 at 08:59


Railroad 'torpedos' used in the US to warn RR engineers of problems ahead were not made with lead or aluminum in recent years. I can't be sure they never were, but the ones I have seen were a red paper square 2.5 cm on a side and about .75 cm thick were made with KClO4 sulfur and some sort of sugar or carbohydrate. The older ones had a lead strap on the to attach to the rails, the newer ones had a thin steel spring, with glass reflecting beads on them. They would soften up when moistened with acetone and you could smell SO2 when you popped a small piece.
View user's profile View All Posts By User
Microtek
International Hazard
*****




Posts: 544
Registered: 23-9-2002
Member Is Offline

Mood: No Mood

[*] posted on 6-5-2006 at 03:19


I'm aware of the oxide film on my Al powder, but I can't use alkanes as they would most probably attack the blender ( which is a cheap one made of plastic ).
View user's profile View All Posts By User
DeAdFX
National Hazard
****




Posts: 339
Registered: 1-7-2005
Location: Brothel
Member Is Offline

Mood: @%&$ing hardcore baby

[*] posted on 6-5-2006 at 19:51


While this post has jack shit to do with Thermite I thought I would contribute this tid bit.

Comments on "Blender Grade Aluminum"
I used denatured alcohol/aluminum foil to make my aluminum powder. A random amount of foil was added into a blender and blended for 5 seconds. I repeated this for awhile until I assumed I had about 100grams of foil in the blender. Enough alcohol was added to the blender to cover the Aluminum foil/powder/whatever the hell. I blended the mix for about 20 or so hours over a 5 day period.

The particles resulting from this mix were fairly large. I would assume 20-100 mesh(calculated by eye). Most in the 50 range. However I did get some really smally floaty shit when I filtered this powder. I didn't burn it but I assumed it was charcoal(fairly dark). I have not seen German dark Aluminum before so I cannot make any good assumptions.

I let the powder dry out for about 1-2 or so hours and then I proceded to burn. The powdered mess burned after heated by the flame of a butane torch for 20 seconds. This was probably because of the alcohol and lack of aluminum oxide.


Summary/Conclusion... Blender grade aluminum is between shit and better than having nothing. I personaly do not believe it is worth 20+ hours of monitored button pushing for some aluminum powder. Having easy access to good quality aluminum powder is obviously a major influence on my conclusion.
View user's profile View All Posts By User
Microtek
International Hazard
*****




Posts: 544
Registered: 23-9-2002
Member Is Offline

Mood: No Mood

[*] posted on 9-5-2006 at 23:58


Well, that differs enormously from my results. When blending, it is necessary to use a certain minimum amount of foil/powder and a certain maximum ratio of ethanol/foil. Otherwise the slurry will be too thin to offer the required shear resistance, and will simply be stirred.
The capabilities of your blender is obviously also a factor.
I hypothesize that once the particles have reached a certain size, most of the further size reduction comes from the grinding action of the grains against each other, rather than from the blades themselves.
Once the mix is blended ( about one hour of effective blending time in my experience ) you have a particle size distribution, and if a certain fraction is desired, you need to separate it accordingly. I use a combination of fractional filtration and sedimentation fractioning to get the very fine fractions.
There is only a small amount of the very fine powder ( depending on the amount of grinding of course ) but all of the powder is less than about 50-100 micron in the largest dimension ( and none of it is more than 10 micron in the smallest, since that is the thickness of the foil ).
View user's profile View All Posts By User
Quince
International Hazard
*****




Posts: 773
Registered: 31-1-2005
Location: Vancouver, BC
Member Is Offline

Mood: No Mood

[*] posted on 13-5-2006 at 03:21


Instead of making CuO from CuSO4, do this instead: dehydrate by heating some CuSO4, then mix 8 Al with 3 CuSO4. It's even easier to ignite than the thermite.

I got the idea from my Al/H2SO4 experiment (https://sciencemadness.org/talk/viewthread.php?tid=3485&...)
Works great!

At first I thought the main reaction is 8 Al + 3 CuSO4 --> 4 Al2O3 + 3 CuS, but there is some metallic copper left (unlike the Al/Al2SO4 where there is only a tiny amount of metallic aluminum left). So I'm not sure what's going on; maybe the sulfur just burns off.

[Edited on 13-5-2006 by Quince]




\"One of the surest signs of Conrad\'s genius is that women dislike his books.\" --George Orwell
View user's profile View All Posts By User
12AX7
Post Harlot
*****




Posts: 4803
Registered: 8-3-2005
Location: oscillating
Member Is Offline

Mood: informative

[*] posted on 13-5-2006 at 04:02


IME, Al2S3 and MgS are formed. Even with alkalies: Na2SO4 + Mg, uh err, +5Mg = 2Na(g) + MgS + 4MgO. MgS is left as a brown crust (smelling of H2S) in the reaction dish, while Na of course burns off with a bright orange flame.

If you're thinking alternate sodium thread here, it's too energetic. Should make a good yellow/orange flash comp though.

That's a good point about CuSO4 though, it *would* work that much better, moisture aside.

Tim




Seven Transistor Labs LLC http://seventransistorlabs.com/
Electronic Design, from Concept to Layout.
Need engineering assistance? Drop me a message!
View user's profile Visit user's homepage View All Posts By User This user has MSN Messenger
Quince
International Hazard
*****




Posts: 773
Registered: 31-1-2005
Location: Vancouver, BC
Member Is Offline

Mood: No Mood

[*] posted on 13-5-2006 at 05:38


Where do you get sodium sulfate?

In all my Al+sulfate experiments, I get lots of white Al2O3 powder all over the place; it's the main product of the reactions. I didn't notice but a small amount of yellow Al2S3, and there's only a bit of H2S smell (when I get the residue wet). I also get a good deal of SO2, so it seems much of the sulfur burns away rather than being bound to something else.

[Edited on 13-5-2006 by Quince]




\"One of the surest signs of Conrad\'s genius is that women dislike his books.\" --George Orwell
View user's profile View All Posts By User
Zinc
National Hazard
****




Posts: 472
Registered: 10-5-2006
Member Is Offline

Mood: No Mood

[*] posted on 24-5-2006 at 05:33


How about Au2O3/Al (I think this would be very sensitive)?
View user's profile View All Posts By User
12AX7
Post Harlot
*****




Posts: 4803
Registered: 8-3-2005
Location: oscillating
Member Is Offline

Mood: informative

[*] posted on 24-5-2006 at 05:47


I would think so, too.

:o

Heh, y'think Au2O3 + Mg would be spontaneous? How about Ca? :D

Tim




Seven Transistor Labs LLC http://seventransistorlabs.com/
Electronic Design, from Concept to Layout.
Need engineering assistance? Drop me a message!
View user's profile Visit user's homepage View All Posts By User This user has MSN Messenger
Zinc
National Hazard
****




Posts: 472
Registered: 10-5-2006
Member Is Offline

Mood: No Mood

[*] posted on 26-5-2006 at 11:49


Originally posted by 12AX7

Heh, y'think Au2O3 + Mg would be spontaneous? How about Ca? :D

Tim



Or how about Au2O3 and Cs?:D
View user's profile View All Posts By User
pyrochem
Harmless
*




Posts: 21
Registered: 1-1-2006
Location: United States
Member Is Offline

Mood: No Mood

[*] posted on 2-6-2006 at 16:16


Quote:

Where do you get sodium sulfate?


It is sold as Glauber's Salt, probably in pharmacies. MgSO4 (Epsom salt) would probably also work.

One thing I like to do is take some hydrated MgSO4 and mix it with fine aluminum powder. When heated (indirectly) over a flame, the MgSO4 will fuse and dehydrate to form a solid mass. When this is heated directly or ignited, it flashes with a sort of "pof" noise. It is hard to ignite.
View user's profile View All Posts By User
franklyn
International Hazard
*****




Posts: 3027
Registered: 30-5-2006
Location: Da Big Apple
Member Is Offline

Mood: No Mood

[*] posted on 30-6-2006 at 11:51
Aluminothermy Synthesis ?


The use of Aluminothermy chemistry destructively or to make explosions is a
trivial silly use of a very useful method for the reduction of metals such as
Molybdenum, Tungsten and Titanium from their oxides to cast metal parts
without the need for an expensive foundry furnace. The welding and repair of
large broken structural and mechanical parts in the field makes this an invaluable
application.

A very useful excerpt on these techniques first published in 1910 is here
in pdf -> http://www.keepmyfile.com/download/c17666846651

Additionally a mention of the reduction of Plutonium metal using Calcium
described in The Curve of Binding Energy ->
http://img31.imagevenue.com/img.php?image=82480_P_u_31lo.jpg

It had occurred to me that it might be possible to produce by this same method
ceramic materials that are otherwise very difficult to prepare. I am referring to
Silicon Carbide Sic , Silicon Nitride Si3N4 , Boron Nitride BN, and Boron Carbide
B4C
Of interest is the possible formation of new ceramics made of these in chemical
combination. For example, a related engineered material the machinable ceramic
SiAlON is a reacted mixture of SiN, SiO2, Al2O3 and AlN. See ->
http://www.blackwell-synergy.com/doi/abs/10.1111/j.1551-2916...
A special Glock automatic pistol has a barrel and slide made of this which
enables it to get by metal detectors.

I propose that the Flourides of Boron BF3 and Silicon SiF4 reacted with Sodium
metal and some Cyanide or Cyanogen salt may produce new and useful ceramics.
Two possible mixtures _

6Na + KCN + BF3 + SiF4 -> KF + 6NaF + BN + SiC

20Na + 2KCN + CaNCN + 4BF3 + 3SiF4 -> 2KF + CaF + 4BN + 3SiC


Sodium is chosen because It's Flouride salts have a low melting point, less than
~ 1000° C assuring a fluid quick precipitation of the desired product and the
formation of a water soluble slag. The possible products will depend on what
bonding can result. Boron Carbide for example does not exhibit the expected
stoichiometry forming instead as B4C. There are three basic known molecular
species of the reactants , BN , SiC and Si3N4, if this last is produced then by
default , B4C3 would remain. This is not a known compound , which suggest a
new unknown chemistry.

The production of composite ceramic materials from powders invariably results
in a porous product. Pure solid cast samples of ceramic composites may result
employing a thermite process.

.
View user's profile View All Posts By User
Zinc
National Hazard
****




Posts: 472
Registered: 10-5-2006
Member Is Offline

Mood: No Mood

[*] posted on 13-7-2006 at 07:52


How about PbI2/Al?

[Edited on 13-7-2006 by Zinc]




View user's profile View All Posts By User
FullMetalJacket
Harmless
*




Posts: 3
Registered: 26-7-2006
Member Is Offline

Mood: No Mood

[*] posted on 14-8-2006 at 16:27


From memory, alfoil has a layer of polyethylene over it. I'm probably wrong, though.
View user's profile View All Posts By User This user has MSN Messenger
Quince
International Hazard
*****




Posts: 773
Registered: 31-1-2005
Location: Vancouver, BC
Member Is Offline

Mood: No Mood

[*] posted on 14-8-2006 at 19:18


If it is, wipe it with boiling xylene; that will dissolve a polyethylene coating.



\"One of the surest signs of Conrad\'s genius is that women dislike his books.\" --George Orwell
View user's profile View All Posts By User
not_important
International Hazard
*****




Posts: 3873
Registered: 21-7-2006
Member Is Offline

Mood: No Mood

[*] posted on 14-8-2006 at 23:58


I don't think 'kitchen' aluminium foil is coated, if it was so the its use to cover dishes being cooked in an oven would have hot polythene fuming all over. Even the decorative coloured foils are anodization and dyes, not a coating per say. Packaging is often multiple layers including aluminium and plastics, and some construction foil is too.

franklyn - while I'll agrre with the start of you message, I don't think that the proposal for complex ceramics is going to fly. Both BF3 and SF4 are gases at STP, making it difficult to get enough of them into the reaction vessel; they also are rather reactive. Also, sodium has a rather low boiling point, not the best thing for these sorts of reactions. Use aluminium and you're likely to get AlB12.

Regarding your comment that Goldschmidt produced ceramics would be solid castings seems to be based on some incorrect assumptions. Silicon carbide decomposes as it 'melts', for example. The contraction of a uniform block of melted ceramic would likely be undergoing rather severe stress, resulting in the formation of internal cracks.

The currently used pressed-powder technologies allow much better control of the phases in the material, domain growth, and so on, than simple melt methods. This is because the temperature and pressure can be independently controlled and not need be monotonic; either or both can be 'cycled' during fabrication of the part. In some cases high pressure is needed to get a desired form/phase of a component in the material.

As for B4C3, I suspect that if it can exist at STP it is known, check out carboranes.
View user's profile View All Posts By User
not_important
International Hazard
*****




Posts: 3873
Registered: 21-7-2006
Member Is Offline

Mood: No Mood

[*] posted on 15-8-2006 at 07:56


If you want a simple yet exotic thermite-type reaction, try this:
Quote:
In 1904 K. A. Ktihne (D.R.P. 147,87.1) described a process in which external heating is not necessary, a mixture of aluminium turnings, sulphur and boric acid being ignited by a hot iron rod, the resulting aluminium sulphide, formed as a by-product, being decomposed by water.

At the time what was thought to be formed was crystalline boron, most likely it is actually AlB12 or mixture of aluminium borides. It can appears as transparent, near colourless. very hard crystals of high refractive index (pure boron is a very deep reddish, looking almost black in all but the thin layers)
View user's profile View All Posts By User
Zinc
National Hazard
****




Posts: 472
Registered: 10-5-2006
Member Is Offline

Mood: No Mood

[*] posted on 2-10-2006 at 08:29


Today I and my friend made some MnO2/Mg thermite. We ignited it with a small amount of a mixture of KMnO4 and Al. It burned very fast and bright.



View user's profile View All Posts By User
Mr. Wizard
International Hazard
*****




Posts: 1040
Registered: 30-3-2003
Member Is Offline

Mood: No Mood

[*] posted on 2-10-2006 at 12:07


Quote:
Originally posted by Zinc
Today I and my friend made some MnO2/Mg thermite. We ignited it with a small amount of a mixture of KMnO4 and Al. It burned very fast and bright.

Not ever having tried MnO2 and Mg I can't be sure, but I'd guess it burns easier than KMnO4 and Al. Did it? Some professional thermit mixes are actually started by a Mg mix which is sparked by a Cerium Misch Metal igniter. The mixture actually starts easier from the sparks than from a flame!! The sparks don't seem to have any 'heat' to them, but they obviously have the energy to start the reaction.
View user's profile View All Posts By User
Zinc
National Hazard
****




Posts: 472
Registered: 10-5-2006
Member Is Offline

Mood: No Mood

[*] posted on 4-10-2006 at 06:11


Quote:
Originally posted by Mr. Wizard
Not ever having tried MnO2 and Mg I can't be sure, but I'd guess it burns easier than KMnO4 and Al. Did it?


Yes it did.




View user's profile View All Posts By User
The_Davster
A pnictogen
*******




Posts: 2861
Registered: 18-11-2003
Member Is Offline

Mood: No Mood

[*] posted on 19-11-2006 at 17:57


Kinda Kewl but still amazing.
http://www.youtube.com/watch?v=hNaFWq4JzS8&mode=related&...

I had always wondered about thermite and ice...




View user's profile View All Posts By User
 Pages:  1  ..  6    8    10  ..  24

  Go To Top