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Boron Nitride vs CBN

Ceramic · grade comparison

Boron Nitride and CBN are both ceramic grades. Boron Nitride is lighter (2 g/cm³ vs 3.48 g/cm³ for CBN) and CBN is stiffer (860 GPa vs 45 GPa). On the shop floor, Boron Nitride machines more easily (excellent vs not recommended).

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

CBNChoose it when the part sees heat.

Boron Nitride vs CBN: properties

Boron NitrideCBN

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

45 GPa6.5 Msi
860 GPa125 Msi

Shear Modulus

18 GPa2.6 Msi
405 GPa58.7 Msi

Bulk Modulus

36 GPa5.2 Msi
400 GPa58 Msi

Poisson's Ratio

0.2
0.14

Tensile Strength (Ultimate)

35 MPa5.1 ksi
—

Compressive Strength

90 MPa13.1 ksi
5,000 MPa725 ksi

Flexural Strength

55 MPa8 ksi
—

Fracture Toughness (K_IC)

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

Hardness, Mohs

2
9.9

Hardness, Knoop

—
4,700 HK

Physical

Density and transition temperatures.

Density

2 g/cm³0.07 lb/in³
3.48 g/cm³0.13 lb/in³

Refractive Index

1.75
2.117

Porosity

8%
0%

Same in both: Melting Point (Solidus) 2,973°C5,383 °F

Thermal

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

Thermal Conductivity

33 W/m·K19.1 BTU/hr·ft·°F
740 W/m·K428 BTU/hr·ft·°F

Specific Heat Capacity

800 J/kg·K0.19 BTU/lb·°F
506 J/kg·K0.12 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

2 µm/m·K1.1 µin/in·°F
4.8 µm/m·K2.7 µin/in·°F

Max Service Temperature (continuous)

1,000°C1,832 °F
1,200°C2,192 °F

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

Electrical

Conductivity and insulation.

Electrical Resistivity

1×10¹³ Ω·m3.94×10²⁰ µΩ·in
1×10¹⁰ Ω·m3.94×10¹⁷ µΩ·in

Dielectric Strength

40 kV/mm1,016 V/mil
—

Dielectric Constant (1 MHz)

4.1
7.1

Dissipation Factor (1 MHz)

4×10⁻⁴
—

Volume Resistivity

1×10¹⁵ Ω·cm
1×10¹² Ω·cm

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

70 / 100
93 / 100

Manufacturability

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

Machinability

85 / 100
2 / 100

Polishability

25 / 100
92 / 100

Sintering / Firing Temperature

1,800°C3,272 °F
1,500°C2,732 °F

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

250 MJ/kg107,481 BTU/lb
900 MJ/kg386,931 BTU/lb

Embodied Carbon (primary production)

20 kg CO₂/kg
55 kg CO₂/kg

Embodied Water

120 L/kg14.4 gal/lb
—

Typical Recycled Content

0%
5%

Common Calculations

Ratios derived from the values above.

Specific Stiffness (E / density)

22.5 MN·m/kg
247.1 MN·m/kg

Thermal Diffusivity

20.6 mm²/s
420.2 mm²/s

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 scaleBoron Nitride

Manufacturing and finishing

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

Boron Nitride vs CBN — frequently asked

What is the difference between Boron Nitride and CBN?

Boron Nitride and CBN are both ceramic grades. Boron Nitride is lighter (2 g/cm³ vs 3.48 g/cm³ for CBN) and CBN is stiffer (860 GPa vs 45 GPa). On the shop floor, Boron Nitride machines more easily (excellent vs not recommended).

Which is cheaper, Boron Nitride or CBN?

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, Boron Nitride or CBN?

Boron Nitride. Its machinability rates excellent (85/100) against not recommended (2/100) for CBN.

Ready to make it?

Upload a CAD file and FabDigit prices the part in Boron Nitride and CBN 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.