Project Title:
Low Cost, High Temperature Rocket Nozzle Components
94-1 11.01 5911
Low Cost, High Temperature Rocket Nozzle Components
Abstract:
Carbon fiber reinforced, silicon carbide composite structures have
demonstrated the ability to yield lightweight, strong rocket
nozzles. Current techniques, utilizing chemical vapor infiltration,
are limited to thin wall structures and are expensive due to the
long processing times required. The current technique of converting
an organometallic polymer to a ceramic is also expensive due to the
large number of repetitive cycles required to densify. A new
technique will be developed that will significantly increase yield
of ceramic material from an organometallic polymer, thereby
significantly reducing the number of densification cycles required,
leading to lower costs.
Polycarbosilane (PCS) will be used to produce silicon carbide
through pyrolysis upon heating. As PCS decomposes, it emits
volatile compounds upon heating. In air, the precursor oxidizes
during heating. As preforms are impregnated with a liquid, the PCS
is first diluted in a solvent. All three factors result in poor
yield of ceramic material from the precursor. These problems can be
overcome if PCS could be melted without decomposition or oxidation
before impregnation and conversion. A process similar to that used
in making carbon-carbon composites will be used to accomplish this.
By melting under pressure, ceramic yield will increase
dramatically, thereby lower processing costs.
Rocket nozzles used in commercial launch vehicles will benefit from
the use of advanced composites for a number of reasons. The
composites will be lighter weight than current designs, they will
be more reliable due to simplicity, not requiring complex cooling
systems, and life cycle cost reductions. Specific applications
include nozzle exit cone extensions, rocket nozzles, ACS and divert
thrusters, and other very high temperature applications.
Key Words
Fiber Materials, Inc.
5 Morin Street
Biddeford, ME 04005-4497