C/C vs SiC/SiC
Composite · grade comparison
C/C and SiC/SiC are both composite grades. SiC/SiC is the stronger of the two: tensile strength 300 MPa (43.5 ksi) against 120 MPa (17.4 ksi) for C/C, about 150% more. SiC/SiC is the more ductile: elongation 0.6% versus 0.5% for C/C. C/C is lighter (1.75 g/cm³ vs 2.5 g/cm³ for SiC/SiC) and SiC/SiC is stiffer (230 GPa vs 60 GPa). On the shop floor, C/C machines more easily (fair vs not recommended).
C/CChoose it when weight is the constraint, or when the part is machined in volume.
SiC/SiCChoose it when strength drives the design, or when the part is bent, formed or impact-loaded.
C/C vs SiC/SiC: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all composite grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
How to read these bars
- One bar per material. A full bar is the highest value among all composite grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Elastic (Young's) Modulus
Shear Modulus
Poisson's Ratio
Tensile Strength (Ultimate)
Elongation at Break
Compressive Strength
Compressive Modulus
Flexural Strength
Flexural Modulus
Shear Strength
Fracture Toughness (K_IC)
Bulk Modulus
Physical
Density and transition temperatures.
Density
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Specific Heat Capacity
Thermal Expansion (CTE, 20–100 °C)
Max Service Temperature (continuous)
Min Service Temperature
Max Service Temperature (short-term)
Electrical
Conductivity and insulation.
Electrical Resistivity
Volume Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
Same in both: UV / Weathering Resistance 100 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Polishability
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Embodied Water
Same in both: Typical Recycled Content 0%
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Specific Stiffness (E / density)
Thermal Diffusivity
Thermal Shock Resistance Index
Strength versus weight
Yield strength against density for every composite grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.
Manufacturing and finishing
| Capability | C/C | SiC/SiC |
|---|---|---|
| Default condition | — | — |
| Relative cost | $$$$ High | $$$$ High |
| Min. machined wall | — | — |
| Best machined surface | — | — |
C/C vs SiC/SiC — frequently asked
Is SiC/SiC stronger than C/C?
Yes. SiC/SiC has a typical tensile strength of 300 MPa (43.5 ksi) against 120 MPa (17.4 ksi) for C/C — about 150% more.
Which is cheaper, C/C or SiC/SiC?
Both sit in the same relative cost tier ($$$$, high); the part price will be decided by machining time, tolerance and quantity rather than by the material.
Which is easier to machine, C/C or SiC/SiC?
C/C. Its machinability rates fair (40/100) against not recommended (4/100) for SiC/SiC.
Ready to make it?
Upload a CAD file and FabDigit prices the part in C/C and SiC/SiC side by side — material, machining time, tolerance and finish in one quote. Certified material data ships with the order on request.
Typical handbook values for the conditions named above, normalised for comparison. Hardness on non-Brinell scales is converted approximately for charting only. Request certified data with your order for design-critical properties.