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SiC/SiC vs ZrB2-SiC

Composite · grade comparison

SiC/SiC and ZrB2-SiC are both composite grades. ZrB2-SiC is the stronger of the two: tensile strength 320 MPa (46.4 ksi) against 300 MPa (43.5 ksi) for SiC/SiC, about 7% more. SiC/SiC is lighter (2.5 g/cm³ vs 5.5 g/cm³ for ZrB2-SiC) and ZrB2-SiC is stiffer (490 GPa vs 230 GPa).

SiC/SiCChoose it when weight is the constraint.

ZrB2-SiCChoose it when strength drives the design, or when the part sees heat.

SiC/SiC vs ZrB2-SiC: properties

SiC/SiCZrB2-SiC

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

230 GPa33.4 Msi
490 GPa71.1 Msi

Shear Modulus

95 GPa13.8 Msi
213 GPa30.9 Msi

Bulk Modulus

120 GPa17.4 Msi
227 GPa32.9 Msi

Poisson's Ratio

0.18
0.14

Tensile Strength (Ultimate)

300 MPa43.5 ksi
320 MPa46.4 ksi

Elongation at Break

0.6%
—

Compressive Strength

600 MPa87 ksi
2,500 MPa363 ksi

Compressive Modulus

230 GPa33.4 Msi
—

Flexural Strength

420 MPa60.9 ksi
700 MPa102 ksi

Flexural Modulus

210 GPa30.5 Msi
485 GPa70.3 Msi

Shear Strength

38 MPa5.5 ksi
—

Fracture Toughness (K_IC)

25 MPa·√m22.8 ksi·√in
4.5 MPa·√m4.1 ksi·√in

Physical

Density and transition temperatures.

Density

2.5 g/cm³0.09 lb/in³
5.5 g/cm³0.2 lb/in³

Thermal

How each material carries heat and how hot it can run.

Thermal Conductivity

15 W/m·K8.7 BTU/hr·ft·°F
78 W/m·K45.1 BTU/hr·ft·°F

Specific Heat Capacity

700 J/kg·K0.17 BTU/lb·°F
440 J/kg·K0.11 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

4.3 µm/m·K2.4 µin/in·°F
6 µm/m·K3.3 µin/in·°F

Max Service Temperature (continuous)

1,350°C2,462 °F
1,600°C2,912 °F

Max Service Temperature (short-term)

1,600°C2,912 °F
2,200°C3,992 °F

Same in both: Min Service Temperature -200°C-328 °F

Electrical

Conductivity and insulation.

Electrical Resistivity

0.1 Ω·m3,937,000 µΩ·in
1.5×10⁻⁷ Ω·m5.91 µΩ·in

Volume Resistivity

—
1.5×10⁻⁵ Ω·cm

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

88 / 100
75 / 100

Same in both: UV / Weathering Resistance 100 / 100

Manufacturability

FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.

Machinability

4 / 100
8 / 100

Polishability

55 / 100
80 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

1,500 MJ/kg644,885 BTU/lb
300 MJ/kg128,977 BTU/lb

Embodied Carbon (primary production)

110 kg CO₂/kg
22 kg CO₂/kg

Same in both: Typical Recycled Content 0%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

120 kN·m/kg
58 kN·m/kg

Specific Stiffness (E / density)

92 MN·m/kg
89.1 MN·m/kg

Thermal Diffusivity

8.6 mm²/s
32.2 mm²/s

Thermal Shock Resistance Index

5
8

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.

1101001,000510Density (g/cm³)Yield strength (MPa) — log scale

Manufacturing and finishing

CapabilitySiC/SiCZrB2-SiC
Default condition——
Relative cost$$$$ High$$$$ High
Min. machined wall——
Best machined surface——

SiC/SiC vs ZrB2-SiC — frequently asked

Is ZrB2-SiC stronger than SiC/SiC?

Yes. ZrB2-SiC has a typical tensile strength of 320 MPa (46.4 ksi) against 300 MPa (43.5 ksi) for SiC/SiC — about 7% more.

Which is cheaper, SiC/SiC or ZrB2-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 SiC/SiC over ZrB2-SiC?

Pick SiC/SiC when weight is the constraint. Pick ZrB2-SiC when strength drives the design, or when the part sees heat.

Ready to make it?

Upload a CAD file and FabDigit prices the part in SiC/SiC and ZrB2-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.