Category:
Composite
Material Type:
composite
Alternative Names:
Tags:
Carbon-Carbon Composite (C/C)
Composite
Basic Information
Composition & Structure
Composition:
Carbon fibers in carbon matrix (pyrolytic carbon or CVD carbon)
Microstructure:
Carbon fibers in pyrolytic carbon matrix with fiber-matrix interface
Description
Carbon-carbon composites combine carbon fibers with a carbon matrix, creating a material with exceptional high-temperature performance. Used in aerospace re-entry shields, aircraft brake discs, and rocket nozzles. The material retains strength at temperatures exceeding 2000°C in non-oxidizing environments. Metallographic preparation is challenging because the matrix and fiber have significantly different hardness and fracture toughness.
Mechanical Properties
Hardness:
Shore D 40-70
Hardness Category:
soft
Tensile Strength:
200-350 MPa
Physical Properties
Density:
1.6-1.9 g/cm³
Melting Point:
Sublimes ~3500°C
Material Characteristics
Work Hardening:
No
Magnetic:
No
Corrosion Resistance:
excellent (non-oxidizing environments)
Sectioning
Diamond wafering blade - medium grit / low concentration. Low feed rate with adequate coolant. Carbon fibers crack during sectioning if damage is not minimized. Avoid abrasive cut-off wheels.
Mounting
Cold castable mounting with epoxy resin. Vacuum impregnation recommended to fill porosity. Hot compression mounting NOT recommended.
Grinding
Start at 240 grit SiC (not coarser). Light pressure (15-20 N). Speed: 200 RPM.
Grinding sequence:
Grinding sequence:
- 240 grit: Planar grinding to remove sectioning damage.
- 360 grit: Remove previous scratches (1 min).
- 600 grit: Remove previous scratches (1 min).
- 800 grit: Remove previous scratches (1 min).
- 1200 grit: Remove previous scratches (1 min).
Recommended Sequence:
Polishing
Polishing sequence:
- 1μm diamond: 2 minutes on ATLANTIS pad.
- 0.05μm colloidal silica: 2 minutes CMP on BLACKCHEM pad.
Recommended Sequence:
Etching
Typically examined as-polished. Fiber-matrix structure visible without etching. Polarized light and DIC effective.
Common Etchants:
Heat Treatment
Not applicable — processed through carbonization and graphitization during manufacturing.
Applicable Standards
- ASTM C1039
- ASTM C838
Applications
- Aircraft brake discs
- Rocket nozzles
- Re-entry vehicle heat shields
- Furnace fixtures
Typical Uses
- Aerospace thermal protection
- High-performance friction materials
- Semiconductor processing furnace components
- Formula 1 brake systems