1. What are Carbon-Carbon Composites?
• Amorphous carbon
matrix composite
• Carbon matrix
reinforced by graphitic
carbon fibers
• First developed in
1958, but not
intensively researched
until the Space Shuttle
Program

2. What are C/C Composites?
C/C composites are lightweight, high-
high-
strength composite materials capable
of withstanding temperatures over
3000°C.
3000°
C/C composites use the strength
and modulus of carbon fibers to
reinforce a carbon matrix to resist
the rigors of extreme environments.

3. Carbon-Carbon Composites
• Carbon-Carbon Composites are the
woven mesh of Carbon-fibers.
• Carbon-Carbon Composites are used for
their high strength and modulus of rigidity.
• Carbon-Carbon Composites' structure can
be tailored to meet requirements.
• Carbon-Carbon Composites are light
weight material which can withstand
temperatures up to 3000°C

4. Properties of C/C
Composites
• Excellent Thermal Shock Resistance(Over 2000oC)
• Low Coefficient of Thermal Expansion
• High Modulus of Elasticity ( 200 GPa )
• High Thermal Conductivity ( 100 W/m*K )
• Low Density ( 1830 Kg/m^3 )
• High Strength
• Low Coefficient of Friction ( in Fiber direction )
• Thermal Resistance in non-oxidizing atmosphere
• High Abrasion Resistance
• High Electrical Conductivity
• Non-Brittle Failure

5. Production of C/C
•Three dimensional woven carbon fiber structure
•Pressure impregnation with liquid
•Heat treated at 2550°C
•Impregnation, DENSIFICATION and
graphitization cycle repeated

6. Representative Weave
Constructions

7. Fabrication of C/C Composites
• Liquid Phase Infiltration
• Chemical Vapor Deposition

8. PAN-based carbon fibers (the most popular type of
carbon fibers).
• In this method carbon fibers are produced by
conversion of polyacrylonitrile (PAN) precursor
through the following stages:
Stretching filaments from polyacrylonitrile
precursor and their thermal oxidation at 200°C.
• The filaments are held in
tension.Carbonization in Nitrogen atmosphere
at a temperature about 1200°C for several
hours.
• During this stage non-carbonelements (O,N,H)
volatilize resulting in enrichment of the fibers
with carbon.Graphitization at about 2500°C.

9. Carbon-Carbon Composites
• porous carbon-carbon composites
(carbon bonded carbon fiber (CBCF))
Porosity content 70~90% ⇒high temperature
insulation

10. Liquid Phase Infiltration
• Preparation of C/C fiber pre-form of desired shape and
structure
• Liquid pre-cursor : Petroleum pitch/ Phenolic resin/ Coal
tar
• Pyrolysis (Chemical deposition by heat in absence of O2
• It is processed at 540–1000°C under high pressure
• Pyrolysis cycle is repeated 3 to 10 times for desired
density
• Heat Treatment converts amorphous C into crystalline C
• Temperature range of treatment :1500-3000°C
• Heat treatment increases Modulus of Elasticity and
Strength

11. Manufacturing Process :

12. • Processing of CBCF
Discontinuous fibers
(mm in length)
Ground recycled CBCF
(rework) mixer slurry moulding
binder
(phenolic resin)
water
50% carbon yield porous &
from phenolic anisotropic
vacuum Carbonization High temp heat low pressure Product
drying
(950℃) treatment 99.9%℃
water
(fiber alignment) gaseous
impurities

15. Chemical Vapor
Deposition
• Preparation of C/C fiber pre-form of desired shape
and structure
• Densification of the composite by CVD technique
• Infiltration from pressurized hydrocarbon gases
(Methane /Propane)at 990-1210°C
• Gas is pyrolyzed from deposition on fibre surface
• Process duration depends on thickness of pre-form
• Heat treatment increases Modulus of Elasticity and
Strength
• This process gives higher strength and modulus of
elasticity

16. • Dense carbon-carbon composites
Discontinuous fibers Impregnation with
pyrolysis Carbonization
Continuous fibers  thermosetting resins
2500℃
(phenolic, furan
polyimide)
 pitch
(polynuclear
aromatic
hydrocarbons)
Chemical vapour Dense
deposition Thick
enough?
product

17. Limitation of CVD
• Hydrocarbon Gases Infiltrating into
interfilament surfaces and cracks ,
sometimes these gases deposite on outer
cracks and leave lot of pores
• Reinfiltration and densification required
• Month long process(for specific
applications)

22. – Stress-strain curve
process dependent: Fig 4.30
Form of fiber reinforcement: Fig 4.31

23. – Fatigue property

24. Properties of Carbon-Carbon
http://www.hitco.com/products/corrosion/chemical/index.html

25. Uses of Carbon-Carbon Composites
http://www.fibermateri
• Aircraft, F-1 racing alsinc.com/frSW.htm
cars and train brakes
• Space shuttle nose tip
and leading edges
• Rocket nozzles and
tips http://www.futureshuttle.com/conference/Th
ermalProtectionSystem/Curry_73099.pdf
http://www.fibermaterialsinc.com/frSW.htm

26. Optical Microscopy
Sample 3:

27. SEM Images
Sample 3:

28. Application
• High Performance Braking System
• Refractory Material
• Hot-Pressed Dies(brake pads)
• Turbo-Jet Engine Components
• Heating Elements
• Missile Nose-Tips
• Rocket Motor Throats
• Leading Edges(Space Shuttle, Agni missile)
• Heat Shields
• X-Ray Targets

29. Applications
• NASA thermal protection systems
• Nozzle throat inserts
• Nosetips & leading edges
• Space motor nozzles

30. Products
• Variety of high
temperature
applications.

31. Heat Shields
• Baffle Heat Shield
• Flexi Heat Shield

32. Disadvantage :
• Low oxidation resistance
• Reacts with Oxygen at temperature above
490°C

33. Protection Method:
• Ceramic coatings(Carbides/
Nitrides/oxides of Si,Zr,Ta,Al etc.)
• Physical vapor deposition
• Plasma spraying
• Injecting with inorganic salts , borate &
silicate glass.
• Replacement of C/C matrix material by
Si-C.(inhibitors of B, Si, Zr compounds)