Complicated, that composite stuff. What are your nozzle dimensions? What about
a graphite nozzle?
jd
-----Original Message-----
From: arocket-bounce@xxxxxxxxxxxxx [mailto:arocket-bounce@xxxxxxxxxxxxx] On
Behalf Of Oliver Arend (Redacted sender "oarend" for DMARC)
Sent: zondag 6 december 2015 12:35
To: arocket@xxxxxxxxxxxxx
Subject: [AR] How to make carbon-carbon composites?
After some recent discussions about nozzle materials and thinking back to a
class I had in university, I was wondering how to make carbon-carbon
composites, and whether this is feasible for amateurs/hobbyists.
From what I understand (having read the Wikipedia article ;-), first a carbon
fiber reinforced part is made in the classic way.
Then the part is pyrolyzed, i. e. heated in the absence of oxygen such that the
matrix decomposes and the volatile parts evaporate to leave a pure carbon
matrix.
Since the matrix is now very porous, a gas like acetylene has to be passed
through the part so the pores will be filled with carbon.
So I have a couple of questions:
1. Which resin can be used to manufacture the original CFRP part? Epoxy?
Phenolic? Anything?
2. Is there really the need for additional "carbonization" after pyrolysis if I
want to use it as a combustion chamber or a nozzle?
3. Are there any other big obstacles I haven't thought of?
Pyrolysis shouldn't be too hard using e. g. a steel container and a CO2
atmosphere at maybe 1000 °C?
Oliver