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Potassium dichromate VS Ammonium dichromate in strobe rockets


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#1 willowchar

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Posted 25 February 2021 - 07:19 PM

Is it possible that ammonium dichromate will produce more efficient combustion and louder pops in strobe propellant verses using Potassium dichromate?

 

Thanks:)



#2 justvisiting

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Posted 25 February 2021 - 07:36 PM

I don't know the answer to your question, but I do know that the (probably) most knowledgeable man in pyro says that ammonium dichromate can be used instead of the potassium salt in strobe propellant- just in case there is a safety concern :)



#3 ZavodKirova

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Posted 06 March 2021 - 12:35 AM

Yes, you can. Ammonium dichromate is a more effective catalyst than potassium dichromate for AP. The claps in the strobe fuel really get louder. Loudest fuel received: 60 AP/ 25 mGal/15 LiSO4 / +2.5 A Dichomate +2.5 K Dichomate

#4 a_bab

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Posted 09 March 2021 - 12:33 AM

I used it once because I was lacking the K version.
But at the time tbh my spindle wasn't the best so I couldn't judge on the sound. It did work however.
There is no reason, chemically speaking, why it wouldn't work.

But, AD is really unstable so I don't know how safe it is, for a compo that cannot be stored for long.
Some sensibility tests are needed. 
 



#5 SharkWhisperer

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Posted 18 March 2021 - 06:38 PM

I used it once because I was lacking the K version.
But at the time tbh my spindle wasn't the best so I couldn't judge on the sound. It did work however.
There is no reason, chemically speaking, why it wouldn't work.

But, AD is really unstable so I don't know how safe it is, for a compo that cannot be stored for long.
Some sensibility tests are needed. 
 

AD by itself is very stable--had a bottle sitting on a shelf for many years with no issue. The stuff of grade-school "volcano" models--voluminous fulminating green ash with sparks. Before most realized the chromium toxicity/carcinogenic issues. In comps, I cannot comment on AC stability--I pretty much use if for passivating Mg powders only, and never noted a difference in performance or storage characteristics of comps with Mg passivated using AC, or the potassium/sodium salts. But never did a side-by-side comparison.

 

For rocket fuels, I don't have much experience with strobe fuels, so cannot comment. One might intuitively guess that the ammonium ion would produce less voluminous solid slag than alkali metal dichromates (think the potassium carbonate issue with BP fuels vs the gaseous ammonium product of APCPs), but then again remember that voluminous green ash with AC (and guessing likely with other dichromates)...






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