Si3N4/SiCw vs SiC/SiC
Composite · grade comparison
Si3N4/SiCw and SiC/SiC are both composite grades. Si3N4/SiCw is the stronger of the two: tensile strength 500 MPa (72.5 ksi) against 300 MPa (43.5 ksi) for SiC/SiC, about 67% more. In exchange, SiC/SiC is the more ductile: elongation 0.6% versus 0.15% for Si3N4/SiCw. SiC/SiC is lighter (2.5 g/cm³ vs 3.22 g/cm³ for Si3N4/SiCw) and Si3N4/SiCw is stiffer (320 GPa vs 230 GPa).
Si3N4/SiCwChoose it when strength drives the design.
SiC/SiCChoose it when the part is bent, formed or impact-loaded, or when weight is the constraint.
Si3N4/SiCw 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
Bulk Modulus
Poisson's Ratio
Tensile Strength (Ultimate)
Elongation at Break
Compressive Strength
Flexural Strength
Flexural Modulus
Shear Strength
Fracture Toughness (K_IC)
Compressive Modulus
Physical
Density and transition temperatures.
Density
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Thermal Expansion (CTE, 20–100 °C)
Max Service Temperature (continuous)
Max Service Temperature (short-term)
Same in both: Specific Heat Capacity 700 J/kg·K0.17 BTU/lb·°F · Min Service Temperature -200°C-328 °F
Electrical
Conductivity and insulation.
Electrical Resistivity
Dielectric Constant (1 MHz)
Volume Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Corrosion Resistance 88 / 100 · UV / Weathering Resistance 100 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Polishability
Same in both: Machinability 4 / 100
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
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 | Si3N4/SiCw | SiC/SiC |
|---|---|---|
| Default condition | — | — |
| Relative cost | $$$$ High | $$$$ High |
| Min. machined wall | — | — |
| Best machined surface | — | — |
Si3N4/SiCw vs SiC/SiC — frequently asked
Is Si3N4/SiCw stronger than SiC/SiC?
Yes. Si3N4/SiCw has a typical tensile strength of 500 MPa (72.5 ksi) against 300 MPa (43.5 ksi) for SiC/SiC — about 67% more.
Which is cheaper, Si3N4/SiCw or SiC/SiC?
Both sit in the same relative cost tier ($$$$, high); the part price will be decided by machining time, tolerance and quantity rather than by the material.
When should I choose Si3N4/SiCw over SiC/SiC?
Pick Si3N4/SiCw when strength drives the design. Pick SiC/SiC when the part is bent, formed or impact-loaded, or when weight is the constraint.
Ready to make it?
Upload a CAD file and FabDigit prices the part in Si3N4/SiCw 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.