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B4C vs Graphite

Ceramic · grade comparison

B4C and Graphite are both ceramic grades. B4C is the stronger of the two: tensile strength 300 MPa (43.5 ksi) against 30 MPa (4.35 ksi) for Graphite, about 10 times as much. Graphite is lighter (1.78 g/cm³ vs 2.51 g/cm³ for B4C) and B4C is stiffer (450 GPa vs 11 GPa). On the shop floor, Graphite machines more easily (excellent vs not recommended).

B4CChoose it when strength drives the design, or when the part sees heat.

GraphiteChoose it when weight is the constraint, or when the part is machined in volume.

B4C vs Graphite: properties

B4CGraphite

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

450 GPa65.3 Msi
11 GPa1.6 Msi

Shear Modulus

190 GPa27.6 Msi
4.5 GPa0.65 Msi

Bulk Modulus

240 GPa34.8 Msi
7 GPa0.94 Msi

Poisson's Ratio

0.17
0.2

Tensile Strength (Ultimate)

300 MPa43.5 ksi
30 MPa4.4 ksi

Compressive Strength

2,900 MPa421 ksi
90 MPa13.1 ksi

Flexural Strength

400 MPa58 ksi
50 MPa7.3 ksi

Shear Strength

260 MPa37.7 ksi
28 MPa4.1 ksi

Fracture Toughness (K_IC)

3 MPa·√m2.7 ksi·√in
1 MPa·√m0.91 ksi·√in

Hardness, Vickers

3,000 HV
—

Hardness, Knoop

2,900 HK
—

Hardness, Mohs

9.5
1.5

Physical

Density and transition temperatures.

Density

2.51 g/cm³0.09 lb/in³
1.78 g/cm³0.06 lb/in³

Melting Point (Solidus)

2,450°C4,442 °F
3,650°C6,602 °F

Porosity

0.5%
12%

Thermal

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

Thermal Conductivity

35 W/m·K20.2 BTU/hr·ft·°F
110 W/m·K63.6 BTU/hr·ft·°F

Specific Heat Capacity

960 J/kg·K0.23 BTU/lb·°F
710 J/kg·K0.17 BTU/lb·°F

Max Service Temperature (continuous)

800°C1,472 °F
450°C842 °F

Min Service Temperature

-269°C-452 °F
-200°C-328 °F

Same in both: Thermal Expansion (CTE, 20–100 °C) 4.5 µm/m·K2.5 µin/in·°F

Electrical

Conductivity and insulation.

Electrical Resistivity

0.05 Ω·m1,968,500 µΩ·in
1.1×10⁻⁵ Ω·m433 µΩ·in

Volume Resistivity

5 Ω·cm
0 Ω·cm

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

90 / 100
80 / 100

Manufacturability

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

Machinability

3 / 100
92 / 100

Polishability

85 / 100
35 / 100

Sintering / Firing Temperature

2,150°C3,902 °F
2,900°C5,252 °F

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

260 MJ/kg111,780 BTU/lb
120 MJ/kg51,591 BTU/lb

Embodied Carbon (primary production)

22 kg CO₂/kg
9 kg CO₂/kg

Embodied Water

120 L/kg14.4 gal/lb
90 L/kg10.8 gal/lb

Typical Recycled Content

0%
10%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

120 kN·m/kg
17 kN·m/kg

Specific Stiffness (E / density)

179.3 MN·m/kg
6.2 MN·m/kg

Thermal Diffusivity

14.5 mm²/s
87 mm²/s

Thermal Shock Resistance Index

5
67

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.

501002005001,000234567Density (g/cm³)Yield strength (MPa) — log scale

Manufacturing and finishing

CapabilityB4CGraphite
Default condition——
Relative cost$$$$ High$$$$ High
Min. machined wall——
Best machined surface——

B4C vs Graphite — frequently asked

Is B4C stronger than Graphite?

Yes. B4C has a typical tensile strength of 300 MPa (43.5 ksi) against 30 MPa (4.35 ksi) for Graphite — about 10 times as much.

Which is cheaper, B4C or Graphite?

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, B4C or Graphite?

Graphite. Its machinability rates excellent (92/100) against not recommended (3/100) for B4C.

Ready to make it?

Upload a CAD file and FabDigit prices the part in B4C and Graphite 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.