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Silicon Nitride vs Boron Nitride and 2 more: properties

Silicon NitrideBoron NitrideAlNSialon

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

310 GPa45 Msi
45 GPa6.5 Msi
320 GPa46.4 Msi
288 GPa41.8 Msi

Shear Modulus

122 GPa17.7 Msi
18 GPa2.6 Msi
130 GPa18.9 Msi
113 GPa16.4 Msi

Bulk Modulus

222 GPa32.2 Msi
36 GPa5.2 Msi
200 GPa29 Msi
205 GPa29.7 Msi

Poisson's Ratio

0.27
0.2
0.24
0.27

Tensile Strength (Ultimate)

450 MPa65.3 ksi
35 MPa5.1 ksi
200 MPa29 ksi
350 MPa50.8 ksi

Elongation at Break

0%

Compressive Strength

3,000 MPa435 ksi
90 MPa13.1 ksi
2,100 MPa305 ksi
3,500 MPa508 ksi

Flexural Strength

800 MPa116 ksi
55 MPa8 ksi
330 MPa47.9 ksi
945 MPa137 ksi

Fracture Toughness (K_IC)

6.5 MPa·√m5.9 ksi·√in
1 MPa·√m0.91 ksi·√in
2.7 MPa·√m2.5 ksi·√in
7.7 MPa·√m7 ksi·√in

Hardness, Vickers

1,500 HV
1,100 HV
1,550 HV

Hardness, Knoop

1,500 HK
1,200 HK
1,450 HK

Hardness, Mohs

9
2
7.5
9

Physical

Density and transition temperatures.

Density

3.22 g/cm³0.12 lb/in³
2 g/cm³0.07 lb/in³
3.26 g/cm³0.12 lb/in³
3.25 g/cm³0.12 lb/in³

Melting Point (Solidus)

1,900°C3,452 °F
2,973°C5,383 °F
2,200°C3,992 °F
1,800°C3,272 °F

Light Transmission

0%

Porosity

0.5%
8%
0.2%
0.3%

Refractive Index

1.75
2.15

Thermal

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

Thermal Conductivity

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
21 W/m·K12.1 BTU/hr·ft·°F

Specific Heat Capacity

700 J/kg·K0.17 BTU/lb·°F
800 J/kg·K0.19 BTU/lb·°F
740 J/kg·K0.18 BTU/lb·°F
690 J/kg·K0.16 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

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
3 µm/m·K1.7 µin/in·°F

Max Service Temperature (continuous)

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

Min Service Temperature

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

Electrical

Conductivity and insulation.

Electrical Resistivity

1×10¹² Ω·m3.94×10¹⁹ µΩ·in
1×10¹³ Ω·m3.94×10²⁰ µΩ·in
1×10¹² Ω·m3.94×10¹⁹ µΩ·in
1×10¹¹ Ω·m3.94×10¹⁸ µΩ·in

Dielectric Strength

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

Dielectric Constant (1 MHz)

8
4.1
8.8
7.9

Dissipation Factor (1 MHz)

0.001
4×10⁻⁴
5×10⁻⁴
0.002

Volume Resistivity

1×10¹⁴ Ω·cm
1×10¹⁵ Ω·cm
1×10¹⁴ Ω·cm
1×10¹³ Ω·cm

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

92 / 100
70 / 100
85 / 100
90 / 100

Manufacturability

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

Machinability

5 / 100
85 / 100
5 / 100
4 / 100

Polishability

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

Sintering / Firing Temperature

1,750°C3,182 °F
1,800°C3,272 °F
1,800°C3,272 °F
1,750°C3,182 °F

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

170 MJ/kg73,087 BTU/lb
250 MJ/kg107,481 BTU/lb
280 MJ/kg120,378 BTU/lb
230 MJ/kg98,882 BTU/lb

Embodied Carbon (primary production)

12 kg CO₂/kg
20 kg CO₂/kg
22 kg CO₂/kg
14 kg CO₂/kg

Embodied Water

220 L/kg26.4 gal/lb
120 L/kg14.4 gal/lb
300 L/kg35.9 gal/lb
250 L/kg30 gal/lb

Same in both: Typical Recycled Content 0%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

140 kN·m/kg
18 kN·m/kg
61 kN·m/kg
108 kN·m/kg

Specific Stiffness (E / density)

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

Thermal Diffusivity

11.1 mm²/s
20.6 mm²/s
74.6 mm²/s
9.4 mm²/s

Thermal Shock Resistance Index

11
13
26
9

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

CapabilitySilicon NitrideBoron NitrideAlNSialon
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 Silicon Nitride and Boron 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.