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HfB2 vs Silicon Nitride

Ceramic · grade comparison

HfB2 and Silicon Nitride are both ceramic grades. HfB2 is harder — 2,800 HV against 1,500 HV for Silicon Nitride — which matters for wear surfaces and threads. Silicon Nitride is lighter (3.22 g/cm³ vs 11.1 g/cm³ for HfB2) and HfB2 is stiffer (480 GPa vs 310 GPa).

HfB2Choose it when surface hardness matters.

Silicon NitrideChoose it when weight is the constraint, or when the part sees heat.

HfB2 vs Silicon Nitride: properties

HfB2Silicon Nitride

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

480 GPa69.6 Msi
310 GPa45 Msi

Shear Modulus

213 GPa30.9 Msi
122 GPa17.7 Msi

Bulk Modulus

212 GPa30.7 Msi
222 GPa32.2 Msi

Poisson's Ratio

0.12
0.27

Compressive Strength

1,800 MPa261 ksi
3,000 MPa435 ksi

Flexural Strength

380 MPa55.1 ksi
800 MPa116 ksi

Fracture Toughness (K_IC)

3.8 MPa·√m3.5 ksi·√in
6.5 MPa·√m5.9 ksi·√in

Hardness, Vickers

2,800 HV
1,500 HV

Hardness, Knoop

2,600 HK
1,500 HK

Tensile Strength (Ultimate)

—
450 MPa65.3 ksi

Elongation at Break

—
0%

Same in both: Hardness, Mohs 9

Physical

Density and transition temperatures.

Density

11.1 g/cm³0.4 lb/in³
3.22 g/cm³0.12 lb/in³

Melting Point (Solidus)

3,380°C6,116 °F
1,900°C3,452 °F

Porosity

1.5%
0.5%

Light Transmission

—
0%

Thermal

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

Thermal Conductivity

104 W/m·K60.1 BTU/hr·ft·°F
25 W/m·K14.4 BTU/hr·ft·°F

Specific Heat Capacity

245 J/kg·K0.06 BTU/lb·°F
700 J/kg·K0.17 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

5.8 µm/m·K3.2 µin/in·°F
3.2 µm/m·K1.8 µin/in·°F

Max Service Temperature (continuous)

1,100°C2,012 °F
1,200°C2,192 °F

Min Service Temperature

-250°C-418 °F
-269°C-452 °F

Electrical

Conductivity and insulation.

Electrical Resistivity

1×10⁻⁷ Ω·m3.94 µΩ·in
1×10¹² Ω·m3.94×10¹⁹ µΩ·in

Volume Resistivity

1×10⁻⁵ Ω·cm
1×10¹⁴ Ω·cm

Dielectric Strength

—
15 kV/mm381 V/mil

Dielectric Constant (1 MHz)

—
8

Dissipation Factor (1 MHz)

—
0.001

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

70 / 100
92 / 100

Manufacturability

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

Polishability

80 / 100
92 / 100

Sintering / Firing Temperature

2,100°C3,812 °F
1,750°C3,182 °F

Same in both: Machinability 5 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

1,500 MJ/kg644,885 BTU/lb
170 MJ/kg73,087 BTU/lb

Embodied Carbon (primary production)

110 kg CO₂/kg
12 kg CO₂/kg

Embodied Water

—
220 L/kg26.4 gal/lb

Same in both: Typical Recycled Content 0%

Common Calculations

Ratios derived from the values above.

Specific Stiffness (E / density)

43.2 MN·m/kg
96.3 MN·m/kg

Thermal Diffusivity

38.2 mm²/s
11.1 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 Nitride

Manufacturing and finishing

CapabilityHfB2Silicon Nitride
Default condition——
Relative cost$$$$ High$$$$ High
Min. machined wall——
Best machined surface——

HfB2 vs Silicon Nitride — frequently asked

What is the difference between HfB2 and Silicon Nitride?

HfB2 and Silicon Nitride are both ceramic grades. HfB2 is harder — 2,800 HV against 1,500 HV for Silicon Nitride — which matters for wear surfaces and threads. Silicon Nitride is lighter (3.22 g/cm³ vs 11.1 g/cm³ for HfB2) and HfB2 is stiffer (480 GPa vs 310 GPa).

Which is cheaper, HfB2 or Silicon Nitride?

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.

When should I choose HfB2 over Silicon Nitride?

Pick HfB2 when surface hardness matters. Pick Silicon Nitride when weight is the constraint, or when the part sees heat.

Ready to make it?

Upload a CAD file and FabDigit prices the part in HfB2 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.