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C/SiC vs Ox/Ox

Composite · grade comparison

C/SiC and Ox/Ox are both composite grades. Ox/Ox is the stronger of the two: tensile strength 190 MPa (27.6 ksi) against 150 MPa (21.8 ksi) for C/SiC, about 27% more. C/SiC is lighter (2.1 g/cm³ vs 2.75 g/cm³ for Ox/Ox) and Ox/Ox is stiffer (75 GPa vs 65 GPa).

C/SiCChoose it when weight is the constraint, or when the part sees heat.

Ox/OxChoose it when strength drives the design.

C/SiC vs Ox/Ox: properties

C/SiCOx/Ox

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

65 GPa9.4 Msi
75 GPa10.9 Msi

Poisson's Ratio

0.17
0.12

Tensile Strength (Ultimate)

150 MPa21.8 ksi
190 MPa27.6 ksi

Compressive Strength

500 MPa72.5 ksi
200 MPa29 ksi

Flexural Strength

220 MPa31.9 ksi
250 MPa36.3 ksi

Flexural Modulus

70 GPa10.2 Msi
65 GPa9.4 Msi

Shear Strength

28 MPa4.1 ksi
10 MPa1.5 ksi

Fracture Toughness (K_IC)

15 MPa·√m13.7 ksi·√in
8 MPa·√m7.3 ksi·√in

Compressive Modulus

—
70 GPa10.2 Msi

Same in both: Shear Modulus 25 GPa3.6 Msi · Elongation at Break 0.3%

Physical

Density and transition temperatures.

Density

2.1 g/cm³0.08 lb/in³
2.75 g/cm³0.1 lb/in³

Water Absorption (24 h)

0.2%
—

Water Absorption (Saturation)

—
8%

Thermal

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

Thermal Conductivity

20 W/m·K11.6 BTU/hr·ft·°F
2 W/m·K1.2 BTU/hr·ft·°F

Specific Heat Capacity

750 J/kg·K0.18 BTU/lb·°F
1,000 J/kg·K0.24 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

2.5 µm/m·K1.4 µin/in·°F
6 µm/m·K3.3 µin/in·°F

Max Service Temperature (continuous)

1,350°C2,462 °F
1,200°C2,192 °F

Max Service Temperature (short-term)

1,650°C3,002 °F
1,300°C2,372 °F

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

Electrical

Conductivity and insulation.

Electrical Resistivity

0.001 Ω·m39,370 µΩ·in
1×10¹⁰ Ω·m3.94×10¹⁷ µΩ·in

Dielectric Constant (1 MHz)

—
5

Dissipation Factor (1 MHz)

—
0.008

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

80 / 100
92 / 100

Same in both: UV / Weathering Resistance 100 / 100

Manufacturability

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

Machinability

10 / 100
15 / 100

Polishability

60 / 100
25 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

700 MJ/kg300,946 BTU/lb
600 MJ/kg257,954 BTU/lb

Same in both: Embodied Carbon (primary production) 45 kg CO₂/kg · Typical Recycled Content 0%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

71 kN·m/kg
69 kN·m/kg

Specific Stiffness (E / density)

31 MN·m/kg
27.3 MN·m/kg

Thermal Diffusivity

12.7 mm²/s
0.7 mm²/s

Thermal Shock Resistance Index

18
1

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

CapabilityC/SiCOx/Ox
Default condition——
Relative cost$$$$ High$$$$ High
Min. machined wall——
Best machined surface——

C/SiC vs Ox/Ox — frequently asked

Is Ox/Ox stronger than C/SiC?

Yes. Ox/Ox has a typical tensile strength of 190 MPa (27.6 ksi) against 150 MPa (21.8 ksi) for C/SiC — about 27% more.

Which is cheaper, C/SiC or Ox/Ox?

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/SiC or Ox/Ox?

Ox/Ox. Its machinability rates poor (15/100) against not recommended (10/100) for C/SiC.

Ready to make it?

Upload a CAD file and FabDigit prices the part in C/SiC and Ox/Ox 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.