Al2O3/SiCw vs Si3N4/SiCw
Composite · grade comparison
Al2O3/SiCw and Si3N4/SiCw are both composite grades. Si3N4/SiCw is the stronger of the two: tensile strength 500 MPa (72.5 ksi) against 350 MPa (50.8 ksi) for Al2O3/SiCw, about 43% more. Si3N4/SiCw is the more ductile: elongation 0.15% versus 0.1% for Al2O3/SiCw. Si3N4/SiCw is lighter (3.22 g/cm³ vs 3.74 g/cm³ for Al2O3/SiCw) and Al2O3/SiCw is stiffer (390 GPa vs 320 GPa).
Si3N4/SiCwChoose it when strength drives the design, or when the part is bent, formed or impact-loaded.
Al2O3/SiCw vs Si3N4/SiCw: 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
Flexural Strength
Flexural Modulus
Shear Strength
Fracture Toughness (K_IC)
Same in both: Compressive Strength 3,000 MPa435 ksi
Physical
Density and transition temperatures.
Density
Water Absorption (24 h)
Thermal
How each material carries heat and how hot it can run.
Specific Heat Capacity
Thermal Expansion (CTE, 20–100 °C)
Max Service Temperature (continuous)
Same in both: Thermal Conductivity 32 W/m·K18.5 BTU/hr·ft·°F · Min Service Temperature -200°C-328 °F · Max Service Temperature (short-term) 1,500°C2,732 °F
Electrical
Conductivity and insulation.
Electrical Resistivity
Dielectric Constant (1 MHz)
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)
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 | Al2O3/SiCw | Si3N4/SiCw |
|---|---|---|
| Default condition | — | — |
| Relative cost | $$$$ High | $$$$ High |
| Min. machined wall | — | — |
| Best machined surface | — | — |
Al2O3/SiCw vs Si3N4/SiCw — frequently asked
Is Si3N4/SiCw stronger than Al2O3/SiCw?
Yes. Si3N4/SiCw has a typical tensile strength of 500 MPa (72.5 ksi) against 350 MPa (50.8 ksi) for Al2O3/SiCw — about 43% more.
Which is cheaper, Al2O3/SiCw or Si3N4/SiCw?
Both sit in the same relative cost tier ($$$$, high); the part price will be decided by machining time, tolerance and quantity rather than by the material.
When should I choose Al2O3/SiCw over Si3N4/SiCw?
Pick Si3N4/SiCw when strength drives the design, or when the part is bent, formed or impact-loaded.
Ready to make it?
Upload a CAD file and FabDigit prices the part in Al2O3/SiCw and Si3N4/SiCw 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.