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Base material and coating for high pressure Hydrazine and N2O4

Base material and coating for high pressure Hydrazine and N2O4

Base material and coating for high pressure Hydrazine and N2O4

I have two piston cylinders one of which will contain hydrazine (N2H4) and the other nitrogen tetroxide. Both pistons will be pressurized to 1500 psia and need to have a high precision bore. Currently I am looking at coating the cylinders with Xylan 1010 which to my understanding is a resin bonded fluoropolymer with a variety of other additives such as PTFE. A Whitford rep told me he was unsure if the coating would react, but was fairly confident that the coating would work as long as the base material was resistant as well.

I was thinking of using stainless steel 304 or 316 for the base, but have not found enough information on how stainless will react with the two chemicals to feel confident in using it.

I don't have much experience with this type of material selection and don't have a strong background in chemistry so any information or opinions on the coating or base material selection would be appreciated.

RE: Base material and coating for high pressure Hydrazine and N2O4

I work for a company that tests rocket engines so yes these cylinders will be used in testing a bipropellant rocket engine.

Since my original post I have confirmed that stainless steel will work without any problems I just need to find a low friction coating that will not degrade when in contact with the two chemicals.

RE: Base material and coating for high pressure Hydrazine and N2O4

I echo MJCronin's statement as I saw an awful big hole in the ground caused by your aforementioned chemicals.  N2O4 is such a strong oxidizer I would be afraid of any organic coating.   Back when we made the stuff the only gasket we used was Blue African Asbestos.  Hydrazine is another animal as you don't know what it's going to do.
As you know both are very hazardous to your health in more ways than one.

I would definately look at Innerarmor from Sub-One.  The problem is getting a coating that is completely compatible with the two ingredients.  Hopefully you can find a compatibility studies as any test would  have the same problem in handling the chemicals.    
Sub-One may have some recommendations or you might search the NASA databases.
All our equipment was 340L when we made N2O4.  
I think on top of the list would be Cr. as I  recall we had some Cr plated pistons when we made the N2O4.  They were a lot of people happy when we got out the business.  


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