B4C vs RBSiC/SiSiC
Ceramic · grade comparison
B4C and RBSiC/SiSiC are both ceramic grades. B4C is the stronger of the two: tensile strength 300 MPa (43.5 ksi) against 200 MPa (29 ksi) for RBSiC/SiSiC, about 50% more. B4C is harder — 3,000 HV against 2,300 HV for RBSiC/SiSiC — which matters for wear surfaces and threads. B4C is lighter (2.51 g/cm³ vs 3.05 g/cm³ for RBSiC/SiSiC) and B4C is stiffer (450 GPa vs 390 GPa).
B4CChoose it when strength drives the design, or when surface hardness matters.
RBSiC/SiSiCChoose it when the part sees heat.
B4C vs RBSiC/SiSiC: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all ceramic 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 ceramic 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
Tensile Strength (Ultimate)
Compressive Strength
Flexural Strength
Shear Strength
Fracture Toughness (K_IC)
Hardness, Vickers
Hardness, Knoop
Hardness, Mohs
Elongation at Break
Same in both: Poisson's Ratio 0.17
Physical
Density and transition temperatures.
Density
Melting Point (Solidus)
Porosity
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
Electrical
Conductivity and insulation.
Electrical Resistivity
Volume Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Polishability
Sintering / Firing Temperature
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Embodied Water
Typical Recycled Content
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 ceramic grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.
Manufacturing and finishing
| Capability | B4C | RBSiC/SiSiC |
|---|---|---|
| Default condition | — | — |
| Relative cost | $$$$ High | $$$$ High |
| Min. machined wall | — | — |
| Best machined surface | — | — |
B4C vs RBSiC/SiSiC — frequently asked
Is B4C stronger than RBSiC/SiSiC?
Yes. B4C has a typical tensile strength of 300 MPa (43.5 ksi) against 200 MPa (29 ksi) for RBSiC/SiSiC — about 50% more.
Which is cheaper, B4C or RBSiC/SiSiC?
Both sit in the same relative cost tier ($$$$, high); the part price will be decided by machining time, tolerance and quantity rather than by the material.
When should I choose B4C over RBSiC/SiSiC?
Pick B4C when strength drives the design, or when surface hardness matters. Pick RBSiC/SiSiC when the part sees heat.
Ready to make it?
Upload a CAD file and FabDigit prices the part in B4C and RBSiC/SiSiC 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.