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CBN vs Sialon

Ceramic · grade comparison

CBN and Sialon are both ceramic grades. Sialon is lighter (3.25 g/cm³ vs 3.48 g/cm³ for CBN) and CBN is stiffer (860 GPa vs 288 GPa).

SialonChoose it when weight is the constraint.

CBN vs Sialon: properties

CBNSialon

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

860 GPa125 Msi
288 GPa41.8 Msi

Shear Modulus

405 GPa58.7 Msi
113 GPa16.4 Msi

Bulk Modulus

400 GPa58 Msi
205 GPa29.7 Msi

Poisson's Ratio

0.14
0.27

Compressive Strength

5,000 MPa725 ksi
3,500 MPa508 ksi

Fracture Toughness (K_IC)

3 MPa·√m2.7 ksi·√in
7.7 MPa·√m7 ksi·√in

Hardness, Knoop

4,700 HK
1,450 HK

Hardness, Mohs

9.9
9

Tensile Strength (Ultimate)

—
350 MPa50.8 ksi

Flexural Strength

—
945 MPa137 ksi

Hardness, Vickers

—
1,550 HV

Physical

Density and transition temperatures.

Density

3.48 g/cm³0.13 lb/in³
3.25 g/cm³0.12 lb/in³

Melting Point (Solidus)

2,973°C5,383 °F
1,800°C3,272 °F

Refractive Index

2.117
—

Porosity

0%
0.3%

Thermal

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

Thermal Conductivity

740 W/m·K428 BTU/hr·ft·°F
21 W/m·K12.1 BTU/hr·ft·°F

Specific Heat Capacity

506 J/kg·K0.12 BTU/lb·°F
690 J/kg·K0.16 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

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

Same in both: Max Service Temperature (continuous) 1,200°C2,192 °F · Min Service Temperature -200°C-328 °F

Electrical

Conductivity and insulation.

Electrical Resistivity

1×10¹⁰ Ω·m3.94×10¹⁷ µΩ·in
1×10¹¹ Ω·m3.94×10¹⁸ µΩ·in

Dielectric Constant (1 MHz)

7.1
7.9

Volume Resistivity

1×10¹² Ω·cm
1×10¹³ Ω·cm

Dielectric Strength

—
15 kV/mm381 V/mil

Dissipation Factor (1 MHz)

—
0.002

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

93 / 100
90 / 100

Manufacturability

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

Machinability

2 / 100
4 / 100

Polishability

92 / 100
85 / 100

Sintering / Firing Temperature

1,500°C2,732 °F
1,750°C3,182 °F

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

900 MJ/kg386,931 BTU/lb
230 MJ/kg98,882 BTU/lb

Embodied Carbon (primary production)

55 kg CO₂/kg
14 kg CO₂/kg

Typical Recycled Content

5%
0%

Embodied Water

—
250 L/kg30 gal/lb

Common Calculations

Ratios derived from the values above.

Specific Stiffness (E / density)

247.1 MN·m/kg
88.6 MN·m/kg

Thermal Diffusivity

420.2 mm²/s
9.4 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 scale

Manufacturing and finishing

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

CBN vs Sialon — frequently asked

What is the difference between CBN and Sialon?

CBN and Sialon are both ceramic grades. Sialon is lighter (3.25 g/cm³ vs 3.48 g/cm³ for CBN) and CBN is stiffer (860 GPa vs 288 GPa).

Which is cheaper, CBN or Sialon?

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 CBN over Sialon?

Pick Sialon when weight is the constraint.

Ready to make it?

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