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Sialon vs Silicon Carbide

Ceramic · grade comparison

Sialon and Silicon Carbide are both ceramic grades. Sialon is the stronger of the two: tensile strength 350 MPa (50.8 ksi) against 250 MPa (36.3 ksi) for Silicon Carbide, about 40% more. Silicon Carbide is harder — 2,500 HV against 1,550 HV for Sialon — which matters for wear surfaces and threads. Silicon Carbide is lighter (3.15 g/cm³ vs 3.25 g/cm³ for Sialon) and Silicon Carbide is stiffer (410 GPa vs 288 GPa).

SialonChoose it when strength drives the design.

Silicon CarbideChoose it when surface hardness matters, or when weight is the constraint.

Sialon vs Silicon Carbide: properties

SialonSilicon Carbide

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

288 GPa41.8 Msi
410 GPa59.5 Msi

Shear Modulus

113 GPa16.4 Msi
175 GPa25.4 Msi

Bulk Modulus

205 GPa29.7 Msi
220 GPa31.9 Msi

Poisson's Ratio

0.27
0.16

Tensile Strength (Ultimate)

350 MPa50.8 ksi
250 MPa36.3 ksi

Compressive Strength

3,500 MPa508 ksi
3,000 MPa435 ksi

Flexural Strength

945 MPa137 ksi
420 MPa60.9 ksi

Fracture Toughness (K_IC)

7.7 MPa·√m7 ksi·√in
3.5 MPa·√m3.2 ksi·√in

Hardness, Vickers

1,550 HV
2,500 HV

Hardness, Knoop

1,450 HK
2,600 HK

Hardness, Mohs

9
9.3

Physical

Density and transition temperatures.

Density

3.25 g/cm³0.12 lb/in³
3.15 g/cm³0.11 lb/in³

Melting Point (Solidus)

1,800°C3,272 °F
2,730°C4,946 °F

Refractive Index

—
2.65

Same in both: Porosity 0.3%

Thermal

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

Thermal Conductivity

21 W/m·K12.1 BTU/hr·ft·°F
120 W/m·K69.3 BTU/hr·ft·°F

Specific Heat Capacity

690 J/kg·K0.16 BTU/lb·°F
700 J/kg·K0.17 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

3 µm/m·K1.7 µin/in·°F
4 µm/m·K2.2 µin/in·°F

Max Service Temperature (continuous)

1,200°C2,192 °F
1,600°C2,912 °F

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

Electrical

Conductivity and insulation.

Electrical Resistivity

1×10¹¹ Ω·m3.94×10¹⁸ µΩ·in
10 Ω·m3.94×10⁸ µΩ·in

Dielectric Strength

15 kV/mm381 V/mil
—

Dielectric Constant (1 MHz)

7.9
—

Dissipation Factor (1 MHz)

0.002
—

Volume Resistivity

1×10¹³ Ω·cm
1,000 Ω·cm

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

90 / 100
92 / 100

Manufacturability

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

Machinability

4 / 100
3 / 100

Polishability

85 / 100
92 / 100

Sintering / Firing Temperature

1,750°C3,182 °F
2,100°C3,812 °F

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

230 MJ/kg98,882 BTU/lb
80 MJ/kg34,394 BTU/lb

Embodied Carbon (primary production)

14 kg CO₂/kg
5.5 kg CO₂/kg

Embodied Water

250 L/kg30 gal/lb
300 L/kg35.9 gal/lb

Typical Recycled Content

0%
2%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

108 kN·m/kg
79 kN·m/kg

Specific Stiffness (E / density)

88.6 MN·m/kg
130.2 MN·m/kg

Thermal Diffusivity

9.4 mm²/s
54.4 mm²/s

Thermal Shock Resistance Index

9
18

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 Carbide

Manufacturing and finishing

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

Sialon vs Silicon Carbide — frequently asked

Is Sialon stronger than Silicon Carbide?

Yes. Sialon has a typical tensile strength of 350 MPa (50.8 ksi) against 250 MPa (36.3 ksi) for Silicon Carbide — about 40% more.

Which is cheaper, Sialon or Silicon Carbide?

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 Sialon over Silicon Carbide?

Pick Sialon when strength drives the design. Pick Silicon Carbide when surface hardness matters, or when weight is the constraint.

Ready to make it?

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