C/C-SiC
also Sigrasic
A hybrid carbon-fiber composite with a mixed carbon/SiC matrix (liquid-silicon-infiltrated C/C), combining the oxidation resistance of SiC with the toughness of C/C; the standard material for ceramic brake discs.
Reference datasheet — C/C-SiC 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.
Values for the LSI-2D condition
C/C-SiC grades and fills
C/C-SiC is supplied in 5 conditions, soft to hard. LSI-2D is the default FabDigit quotes; the values on this page are for it.
Compare all 5 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
Short/chopped carbon fibre, liquid silicon infiltrated | Near-net-shape pressed short-fibre grade for carbon-ceramic brake discs and clutches — cheapest route, isotropic in-plane, lower strength but excellent wear and thermal shock. | 45 | 0.2 | ||
Needled felt / 3D preform, liquid silicon infiltrated | Needled or 3D-woven preform giving through-thickness reinforcement — pick for thick sections, bolted joints and delamination-critical parts. | 90 | 0.2 | ||
LSI-2DDefault 2D carbon-fabric preform, liquid silicon infiltrated | Standard structural C/C-SiC: highest in-plane strength and damage tolerance, use for panels, hot structures, TPS and nozzle liners. | 110 | 0.3 | ||
PIP C/SiC | Autoclave-friendly route for large thin-walled shells; moderate strength, higher porosity, cheaper tooling than CVI but many densification cycles. | 240 | 0.5 | ||
CVI C/SiC | Highest-performance route: pure SiC matrix, no free silicon, best strength and temperature capability — used for turbine and nozzle hardware, but slow and expensive with ~10–15 % residual porosity. | 300 | 0.6 |
Supply forms, finishes and certifications
Ways C/C-SiC is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
SIC-COAT | SiC/oxide seal-coated | Surface finish |
What is C/C-SiC?
A hybrid carbon-fiber composite with a mixed carbon/SiC matrix (liquid-silicon-infiltrated C/C), combining the oxidation resistance of SiC with the toughness of C/C; the standard material for ceramic brake discs. C/C-SiC has a density of 1.95 g/cm³ (0.0704 lb/in³), heavier than 75% of composite grades. C/C-SiC has a tensile strength of 110 MPa (16 ksi), weaker than 64% of composite grades. Elongation at break is 0.3% and the elastic modulus is 60 GPa (8.7 Msi).
What is C/C-SiC used for?
- high-performance automotive brake discs ("ceramic brakes")
- clutch friction components
- aircraft brake systems
- high-temperature seals
- friction bearings
Advantages
- High service temperature — 1,350°C (2,462 °F), better than 98% of composite grades
- Good UV / weathering resistance — 98/100, better than 85% of composite grades
- Conducts heat well — 20 W/m·K (11.6 BTU/hr·ft·°F), better than 78% of composite grades
Limitations
- High embodied carbon — 60 kg CO₂/kg, worse than 96% of composite grades
- Limited ductility — 0.3%, worse than 95% of composite grades
- Difficult to machine — 8/100, worse than 94% of composite grades
C/C-SiC properties
Typical room-temperature values for C/C-SiC-LSI-2D; bars are the position among composite grades.
Physical1
C/C-SiC has a density of 1.95 g/cm³ (0.0704 lb/in³), heavier than 75% of composite grades.
Mechanical11
C/C-SiC has a tensile strength of 110 MPa (16 ksi), weaker than 64% of composite grades. Elongation at break is 0.3% and the elastic modulus is 60 GPa (8.7 Msi).
Thermal6
C/C-SiC is rated for continuous service to 1,350°C (2,462 °F). It conducts heat at 20 W/m·K (11.6 BTU/hr·ft·°F), better than 78% of composite grades. Thermal expansion is 1.5 µm/m·K (0.833 µin/in·°F).
Electrical1
C/C-SiC has an electrical resistivity of 5×10⁻⁴ Ω·m.
Chemical & Environmental3
Corrosion resistance is very good (75/100), worse than 55% of composite grades. UV resistance is excellent.
Sustainability3
Producing a kilogram of C/C-SiC takes about 900 MJ of energy and emits 60 kg of CO₂ — more than 95% of composite grades. Typical recycled content is 0%.
Manufacturability2
C/C-SiC's machinability is not recommended (8/100, worse than 94% 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-SiC is highlighted; hover a dot for its name, or open the interactive family chart.
Working with C/C-SiC
Is C/C-SiC easy to machine?
Machine the porous C/C preform green with carbide/PCD tooling before siliconization; after conversion only diamond grinding, lapping, waterjet or laser is practical.
Can C/C-SiC be welded?
Not weldable — join by reaction brazing with Si/Ti-based fillers, ceramic adhesives, or mechanical fastening through CMC/metal bushings.
Can C/C-SiC be formed, bent or molded?
Made near-net-shape: prepreg lay-up or warm-pressed chopped-fibre moulding, cure, pyrolysis to C/C, then liquid-Si infiltration at 1450–1650 °C in vacuum; allow ~1–2 % pyrolysis shrinkage.
C/C-SiC 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 |
|---|---|---|
| C (carbon fibre reinforcement)PAN-based fibre, 2D fabric, needled felt or chopped bundles | 35 – 60 | 50 |
| SiC (reaction-formed matrix)formed by Si + pyrolytic C reaction during siliconization | 20 – 45 | 32 |
| Si (residual free silicon)LSI grades only; near zero in CVI/PIP grades | 1 – 15 | 8 |
| C (pyrolytic/resin-derived matrix carbonbalance, plus 1–5 % open porosity | balance |
What surface finishes work on C/C-SiC?
CVD-SiC or SiC/glass seal coats for oxidation protection; friction faces are ground flat; no plating or anodizing, paints are pointless above 400 °C.
Equivalent designations
Standards and trade names that resolve to C/C-SiC in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Trade names
- Sigrasic
How much does C/C-SiC cost?
C/C-SiC is a high-cost composite ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
C/C-SiC — frequently asked
What is C/C-SiC used for?
C/C-SiC is typically used for high-performance automotive brake discs ("ceramic brakes"), clutch friction components, aircraft brake systems, high-temperature seals and friction bearings. In short: standard ceramic brake material; oxidation-resistant C/C upgrade; 1350 °C service temperature.
What is the tensile strength of C/C-SiC?
C/C-SiC has a typical tensile strength of 110 MPa (16 ksi) — weaker than 64% of composite grades. Strength varies by condition: see the 5 listed tempers.
Is C/C-SiC easy to machine?
Not especially — machinability is rated not recommended (8/100, worse than 94% of composite grades). Machine the porous C/C preform green with carbide/PCD tooling before siliconization; after conversion only diamond grinding, lapping, waterjet or laser is practical.
Can C/C-SiC be welded?
Not weldable — join by reaction brazing with Si/Ti-based fillers, ceramic adhesives, or mechanical fastening through CMC/metal bushings.
What surface finishes work on C/C-SiC?
CVD-SiC or SiC/glass seal coats for oxidation protection; friction faces are ground flat; no plating or anodizing, paints are pointless above 400 °C.
Can C/C-SiC be formed, bent or molded?
Made near-net-shape: prepreg lay-up or warm-pressed chopped-fibre moulding, cure, pyrolysis to C/C, then liquid-Si infiltration at 1450–1650 °C in vacuum; allow ~1–2 % pyrolysis shrinkage.
What is the maximum service temperature of C/C-SiC?
C/C-SiC is rated for continuous use to about 1,350°C (2,462 °F), and briefly to 1,700°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does C/C-SiC cost?
C/C-SiC is a high-cost composite ($$$$), 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
- Ceramic Matrix Composites: Fiber Reinforced Ceramics and their Applications (Krenkel, ed.) — Wiley-VCH (2008)
- SIGRASIC C/SiC materials datasheet — SGL Carbon (2022)
- ASM Handbook Vol. 21: Composites — ASM International (2001)
- DLR Institute of Structures and Design — LSI C/C-SiC property reports — DLR (2019)
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.