23 replies to this topic

[Gary]

I have a reference to a inorganic chemistry textbook which states that the amorphous form of elemental boron (appearance-wise, it is a dark brown to black powder) is used in pyrotechnics to produce greens.
Has anyone heard of any formula employing this chemical? Perhaps it might be worth experimenting with it to find out whether or not it is any good for green stars. The active species responsible for the green emission is the BO^. radical. Elemental boron has applications in military pyrotechnics, but in recreational pyrotechnics (fireworks) it is unheard of.

[a_bab]

Apart from it's obvius use for very hot primes (just as silicon, only better and more expensive), I saw some odd military formulas for gasless compositions. But this is offtopic, although I'm sure they both burn greenish

"A mixture of amorphous boron and potassium nitrate in a ratio 75:25 burns rapidly with a brilliant green flame at very high temperature" (Pyrotechnic Chemistry by Kurt Kosanke)

That's got to be a starting point for you.

[fruitfulsteve]

I think Boron is rather toxic and expensive, but i suppose if the tax payer is footing the bill and your trying to kill people expense and toxicity are rather irrelevant to the military

[a_bab]

Boron is expensive, but not toxic. In elementary form is quite inert.

Nevertheless, the military are known to have less concern for the toxicity of the stuff they use. The more the bang, the better for them.

[MDH]

http://mysite.du.edu.../phys/boron.htm

A page that might interest some of you. It's been in my favorites for a while. As I said in the ammonium persulphate thread I was going crazy over boron compounds some time back, particularly copper borate, that must have been when I had favourited it...

[pyrotechnist]

Better question is where do you buy amorphous boron?

Edited by pyrotechnist, 14 January 2010 - 11:41 PM.

[MDH]

From China.

I would guess that industrially boron derivatives are cheaper than boron itself, such as the boranes (though, again the source from outside of industrial quantities is questionable) or the tetra and metaborates.

These should really be explored first....

Edited by MDH, 15 January 2010 - 01:23 PM.

[pyrotechnist]

Boric oxide may seem promising to.

[pyrotechnist]

Tried boric acid which burns green in a flame but when added in a formula seems to either burn white, or blue which is strange so my next test is boric oxide.

[Steve]

Tried boric acid which burns green in a flame but when added in a formula seems to either burn white, or blue which is strange so my next test is boric oxide.

Boric acid isn't great in some formulas as it works a a fire retardant.

It is commonly accepted that the fire retardant mechanism of boric acid is a physical mechanism achieved by the formation of a coating or protective layer on the wood surface at high temperature. Although a char-forming catalytic mechanism has been proposed by some researchers, little direct experimental support has been provided for such a chemical mechanism

The cool thing about boric acid as a colourant is you can disolve it in alcohol/meths to get a liquid fuel which burns very green. Nice if you like fire poi.

[pyrotechnist]

If only you could utilize that colour for pyro would be beautiful.

[MDH]

You CAN... but you are going to need a source which decomposes directly into metallic boron.

http://en.wikipedia....wiki/Decaborane

[Arthur Brown]

Decaborane -like other boranes is a neuro toxin so possibly not a good colourant!

As ever it's a matter of getting the flame chemistry right to get the correct species at the correct temperature to emit their spectrum.

[pyrotechnist]

I believe born is an area in need of testing to get a reasonable or good green flame. I do see lots of good things that can probably be brought to our hobby by this chemical if done right we just need to get the optimal formula for it.

Decaboron is neuron toxin but thinking about it so are a few other chemicals we have I am sure a good pair of gloves will stop it absorbing into your skin and as of yet I am not sure how much you will need for it to be fatal. According to the wiki page which I know can have flaws it burns a bright green flame by itself which is promising and is highly flammable. I can see this being used without an oxidizer maybe?

Edited by pyrotechnist, 27 January 2010 - 10:13 AM.

[crystal palace fireworks]

I believe born is an area in need of testing to get a reasonable or good green flame. I do see lots of good things that can probably be brought to our hobby by this chemical if done right we just need to get the optimal formula for it.

Decaboron is neuron toxin but thinking about it so are a few other chemicals we have I am sure a good pair of gloves will stop it absorbing into your skin and as of yet I am not sure how much you will need for it to be fatal. According to the wiki page which I know can have flaws it burns a bright green flame by itself which is promising and is highly flammable. I can see this being used without an oxidizer maybe?

Might be worth you approaching various chemistry, or medical educational establishements to find paper/studies on such topics,..that way you save see or save time on whats already been tried, tested or experimented with!