C/C
also Carbon-Carbon
A carbon-fiber-reinforced carbon-matrix composite offering extreme thermal stability and low density, though it oxidizes readily above ~450°C in air unless coated; the base material for many C/C-SiC hybrids.
Reference datasheet — C/C is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
C/C grades and fills
C/C is supplied in 7 conditions, soft to hard.
Compare all 7 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
Needled felt (quasi-3D) C/C, thermal-field grade | Low-cost needled non-woven preform densified to medium density — the standard for PV/semiconductor furnace crucibles, guide cylinders and insulation hardware. | 60 | 0.4 | ||
High-purity (halogen-purified) C/C, ash < 20 ppm | Halogen-gas purified grade for silicon single-crystal pulling, SiC epitaxy and semiconductor furnaces where metal contamination is unacceptable. | 70 | 0.4 | ||
High thermal conductivity, mesophase-pitch fiber C/C | Mesophase-pitch fiber reinforcement gives in-plane conductivity several times that of copper per unit mass — for spacecraft radiators, heat spreaders and leading edges. | 80 | 0.25 | ||
Friction (aircraft/racing brake disc) grade C/C | Densified needled/CVI disc stock tuned for stable friction coefficient and huge heat-sink capacity in aircraft and motorsport brakes. | 80 | 0.4 | ||
Resin/pitch impregnation and carbonization matrix | Cheaper, faster route to medium-density C/C for tooling, fixtures and non-critical thermal-field parts; more residual porosity and lower conductivity than CVI. | 90 | 0.4 | ||
Multi-directional (3D/4D) woven or braided C/C preform | Choose when through-thickness strength and delamination resistance matter — rocket nozzle throats, nose tips, thick structural parts. | 130 | 0.7 | ||
Chemical vapor infiltration (pyrolytic carbon) matrix | Highest matrix quality and thermal conductivity, cleanest chemistry — pick for brakes, thermal management and high-purity furnace parts, at the cost of long densification cycles. | 140 | 0.6 |
Supply forms, finishes and certifications
Ways C/C is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
2DDefault | Two-directional woven/laminated C/C, CVI+carbonization densified | Surface finish |
SIC-COAT | SiC-coated / oxidation-protected C/C | Surface finish |
What is C/C?
A carbon-fiber-reinforced carbon-matrix composite offering extreme thermal stability and low density, though it oxidizes readily above ~450°C in air unless coated; the base material for many C/C-SiC hybrids. C/C has a density of 1.75 g/cm³ (0.0632 lb/in³), lighter than 51% of composite grades. C/C has a tensile strength of 120 MPa (17.4 ksi), weaker than 61% of composite grades. Elongation at break is 0.5% and the elastic modulus is 60 GPa (8.7 Msi).
What is C/C used for?
- rocket nozzle throats and exit cones
- aircraft brake discs
- re-entry vehicle nose tips
- hot-pressing dies
- high-temperature furnace fixtures
Advantages
- Good UV / weathering resistance — 100/100, better than 93% of composite grades
- High service temperature — 450°C (842 °F), better than 85% of composite grades
- Conducts heat well — 40 W/m·K (23.1 BTU/hr·ft·°F), better than 83% of composite grades
Limitations
- High embodied carbon — 60 kg CO₂/kg, worse than 96% of composite grades
- Limited ductility — 0.5%, worse than 90% of composite grades
- Hard to polish — 25/100, worse than 76% of composite grades
C/C properties
Typical room-temperature values; bars are the position among composite grades.
Physical1
C/C has a density of 1.75 g/cm³ (0.0632 lb/in³), lighter than 51% of composite grades.
Mechanical11
C/C has a tensile strength of 120 MPa (17.4 ksi), weaker than 61% of composite grades. Elongation at break is 0.5% and the elastic modulus is 60 GPa (8.7 Msi).
Thermal6
C/C is rated for continuous service to 450°C (842 °F). It conducts heat at 40 W/m·K (23.1 BTU/hr·ft·°F), better than 83% of composite grades. Thermal expansion is 1 µm/m·K (0.556 µin/in·°F).
Electrical2
C/C has an electrical resistivity of 2×10⁻⁵ Ω·m.
Chemical & Environmental3
Corrosion resistance is very good (80/100), better than 54% of composite grades. UV resistance is excellent.
Sustainability4
Producing a kilogram of C/C takes about 1,000 MJ of energy and emits 60 kg of CO₂ — more than 97% of composite grades. Typical recycled content is 0%.
Manufacturability2
C/C's machinability is fair (40/100, better than 57% of composite grades).
Common Calculations4
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the composite family
Yield strength against density for every composite grade FabDigit runs. C/C is highlighted; hover a dot for its name, or open the interactive family chart.
Working with C/C
Is C/C easy to machine?
Machine dry with diamond-coated or PCD tools at high speed/low feed and full dust extraction; support laminates to avoid edge delamination, and re-coat any surface where an antioxidation layer is cut through.
Can C/C be welded?
Not weldable — join by carbon/graphite cement, brazing to metals with active Ti/Zr-bearing fillers, or mechanical carbon-composite bolts and pins.
Can C/C be formed, bent or molded?
Net-shape is set at the preform stage (cloth layup, filament winding, braiding or needled felt) followed by CVI and/or resin/pitch impregnation–carbonization cycles and 2000–2800 °C graphitization; expect weeks of densification and only minor final machining allowance.
C/C chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| carbon fiber (PAN or mesophase pitch)volume fraction of reinforcement; woven cloth, needled felt or multi-directional preform | 30 – 60 | 45 |
| Ctotal carbon content | 99 – 100 | 99.9 |
| ash (metallic impurities)< 20 ppm in halogen-purified HP grade | 0 – 0.3 | 0.05 |
| SiC (coating only)0.05–0.5 mm CVD/pack-cementation layer on oxidation-protected variants | ≈ 0 | 0 |
| carbon matrix (pyrolytic carbon / resin-CVI, LPI or hybrid densification; residual open porosity typically 5–15 % | balance |
What surface finishes work on C/C?
Common finishes are CVD SiC conversion coating with phosphate/borosilicate glass sealer for oxidation protection, halogen purification for semiconductor use, and pyrolytic-carbon sealing for particle-free surfaces; no plating or anodizing applies.
Equivalent designations
Standards and trade names that resolve to C/C in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Trade names
- Carbon-Carbon
How much does C/C cost?
C/C is a high-cost composite ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
C/C — frequently asked
What is C/C used for?
C/C is typically used for rocket nozzle throats and exit cones, aircraft brake discs, re-entry vehicle nose tips, hot-pressing dies and high-temperature furnace fixtures. In short: lowest-density CMC; highest conductivity in family; 450 °C uncoated air limit.
What is the tensile strength of C/C?
C/C has a typical tensile strength of 120 MPa (17.4 ksi) — weaker than 61% of composite grades. Strength varies by condition: see the 7 listed tempers.
Is C/C easy to machine?
Not especially — machinability is rated fair (40/100, better than 57% of composite grades). Machine dry with diamond-coated or PCD tools at high speed/low feed and full dust extraction; support laminates to avoid edge delamination, and re-coat any surface where an antioxidation layer is cut through.
Can C/C be welded?
Not weldable — join by carbon/graphite cement, brazing to metals with active Ti/Zr-bearing fillers, or mechanical carbon-composite bolts and pins.
What surface finishes work on C/C?
Common finishes are CVD SiC conversion coating with phosphate/borosilicate glass sealer for oxidation protection, halogen purification for semiconductor use, and pyrolytic-carbon sealing for particle-free surfaces; no plating or anodizing applies.
Can C/C be formed, bent or molded?
Net-shape is set at the preform stage (cloth layup, filament winding, braiding or needled felt) followed by CVI and/or resin/pitch impregnation–carbonization cycles and 2000–2800 °C graphitization; expect weeks of densification and only minor final machining allowance.
What is the maximum service temperature of C/C?
C/C is rated for continuous use to about 450°C (842 °F), and briefly to 2,500°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does C/C cost?
C/C is a high-cost composite ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- ASM Handbook Vol. 21: Composites — Carbon-Carbon Composites — ASM International (2001)
- Carbon-Carbon Materials and Composites (Buckley & Edie) — Noyes Publications / NASA RP-1254 (1993)
- SIGRABOND carbon fiber reinforced carbon — SGL Carbon (2022)
- Carbon-fiber reinforced carbon (CFC) product data — Schunk Carbon Technology (2021)
- C/C composite CX series data — Toyo Tanso (2020)
- ASTM C1341 — Flexural Properties of Continuous Fiber-Reinforced Advanced Ceramic Composites — ASTM (2013)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.