FabDigit

CBN vs Silicon Nitride and 2 more: properties

CBNSilicon NitrideBoron NitrideAlN

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

860 GPa125 Msi
310 GPa45 Msi
45 GPa6.5 Msi
320 GPa46.4 Msi

Shear Modulus

405 GPa58.7 Msi
122 GPa17.7 Msi
18 GPa2.6 Msi
130 GPa18.9 Msi

Bulk Modulus

400 GPa58 Msi
222 GPa32.2 Msi
36 GPa5.2 Msi
200 GPa29 Msi

Poisson's Ratio

0.14
0.27
0.2
0.24

Compressive Strength

5,000 MPa725 ksi
3,000 MPa435 ksi
90 MPa13.1 ksi
2,100 MPa305 ksi

Fracture Toughness (K_IC)

3 MPa·√m2.7 ksi·√in
6.5 MPa·√m5.9 ksi·√in
1 MPa·√m0.91 ksi·√in
2.7 MPa·√m2.5 ksi·√in

Hardness, Knoop

4,700 HK
1,500 HK
1,200 HK

Hardness, Mohs

9.9
9
2
7.5

Tensile Strength (Ultimate)

450 MPa65.3 ksi
35 MPa5.1 ksi
200 MPa29 ksi

Elongation at Break

0%

Flexural Strength

800 MPa116 ksi
55 MPa8 ksi
330 MPa47.9 ksi

Hardness, Vickers

1,500 HV
1,100 HV

Physical

Density and transition temperatures.

Density

3.48 g/cm³0.13 lb/in³
3.22 g/cm³0.12 lb/in³
2 g/cm³0.07 lb/in³
3.26 g/cm³0.12 lb/in³

Melting Point (Solidus)

2,973°C5,383 °F
1,900°C3,452 °F
2,973°C5,383 °F
2,200°C3,992 °F

Refractive Index

2.117
1.75
2.15

Porosity

0%
0.5%
8%
0.2%

Light Transmission

0%

Thermal

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

Thermal Conductivity

740 W/m·K428 BTU/hr·ft·°F
25 W/m·K14.4 BTU/hr·ft·°F
33 W/m·K19.1 BTU/hr·ft·°F
180 W/m·K104 BTU/hr·ft·°F

Specific Heat Capacity

506 J/kg·K0.12 BTU/lb·°F
700 J/kg·K0.17 BTU/lb·°F
800 J/kg·K0.19 BTU/lb·°F
740 J/kg·K0.18 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

4.8 µm/m·K2.7 µin/in·°F
3.2 µm/m·K1.8 µin/in·°F
2 µm/m·K1.1 µin/in·°F
4.4 µm/m·K2.4 µin/in·°F

Max Service Temperature (continuous)

1,200°C2,192 °F
1,200°C2,192 °F
1,000°C1,832 °F
900°C1,652 °F

Min Service Temperature

-200°C-328 °F
-269°C-452 °F
-200°C-328 °F
-200°C-328 °F

Electrical

Conductivity and insulation.

Electrical Resistivity

1×10¹⁰ Ω·m3.94×10¹⁷ µΩ·in
1×10¹² Ω·m3.94×10¹⁹ µΩ·in
1×10¹³ Ω·m3.94×10²⁰ µΩ·in
1×10¹² Ω·m3.94×10¹⁹ µΩ·in

Dielectric Constant (1 MHz)

7.1
8
4.1
8.8

Volume Resistivity

1×10¹² Ω·cm
1×10¹⁴ Ω·cm
1×10¹⁵ Ω·cm
1×10¹⁴ Ω·cm

Dielectric Strength

15 kV/mm381 V/mil
40 kV/mm1,016 V/mil
17 kV/mm432 V/mil

Dissipation Factor (1 MHz)

0.001
4×10⁻⁴
5×10⁻⁴

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

93 / 100
92 / 100
70 / 100
85 / 100

Manufacturability

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

Machinability

2 / 100
5 / 100
85 / 100
5 / 100

Polishability

92 / 100
92 / 100
25 / 100
85 / 100

Sintering / Firing Temperature

1,500°C2,732 °F
1,750°C3,182 °F
1,800°C3,272 °F
1,800°C3,272 °F

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

900 MJ/kg386,931 BTU/lb
170 MJ/kg73,087 BTU/lb
250 MJ/kg107,481 BTU/lb
280 MJ/kg120,378 BTU/lb

Embodied Carbon (primary production)

55 kg CO₂/kg
12 kg CO₂/kg
20 kg CO₂/kg
22 kg CO₂/kg

Typical Recycled Content

5%
0%
0%
0%

Embodied Water

220 L/kg26.4 gal/lb
120 L/kg14.4 gal/lb
300 L/kg35.9 gal/lb

Common Calculations

Ratios derived from the values above.

Specific Stiffness (E / density)

247.1 MN·m/kg
96.3 MN·m/kg
22.5 MN·m/kg
98.2 MN·m/kg

Thermal Diffusivity

420.2 mm²/s
11.1 mm²/s
20.6 mm²/s
74.6 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 scaleSilicon NitrideBoron Nitride

Manufacturing and finishing

CapabilityCBNSilicon NitrideBoron NitrideAlN
Default condition
Relative cost$$$$ High$$$$ High$$$$ High$$$$ High
Min. machined wall
Best machined surface

Ready to make it?

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