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AlN vs Sialon

Ceramic · grade comparison

AlN and Sialon are both ceramic grades. Sialon is the stronger of the two: tensile strength 350 MPa (50.8 ksi) against 200 MPa (29 ksi) for AlN, about 75% more. Sialon is harder — 1,550 HV against 1,100 HV for AlN — which matters for wear surfaces and threads. AlN is stiffer (320 GPa vs 288 GPa) and Sialon runs hotter in service (1,200°C vs 900°C continuous).

SialonChoose it when strength drives the design, or when surface hardness matters.

AlN vs Sialon: properties

AlNSialon

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

320 GPa46.4 Msi
288 GPa41.8 Msi

Shear Modulus

130 GPa18.9 Msi
113 GPa16.4 Msi

Bulk Modulus

200 GPa29 Msi
205 GPa29.7 Msi

Poisson's Ratio

0.24
0.27

Tensile Strength (Ultimate)

200 MPa29 ksi
350 MPa50.8 ksi

Compressive Strength

2,100 MPa305 ksi
3,500 MPa508 ksi

Flexural Strength

330 MPa47.9 ksi
945 MPa137 ksi

Fracture Toughness (K_IC)

2.7 MPa·√m2.5 ksi·√in
7.7 MPa·√m7 ksi·√in

Hardness, Vickers

1,100 HV
1,550 HV

Hardness, Knoop

1,200 HK
1,450 HK

Hardness, Mohs

7.5
9

Physical

Density and transition temperatures.

Density

3.26 g/cm³0.12 lb/in³
3.25 g/cm³0.12 lb/in³

Melting Point (Solidus)

2,200°C3,992 °F
1,800°C3,272 °F

Refractive Index

2.15
—

Porosity

0.2%
0.3%

Thermal

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

Thermal Conductivity

180 W/m·K104 BTU/hr·ft·°F
21 W/m·K12.1 BTU/hr·ft·°F

Specific Heat Capacity

740 J/kg·K0.18 BTU/lb·°F
690 J/kg·K0.16 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

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

Max Service Temperature (continuous)

900°C1,652 °F
1,200°C2,192 °F

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

Electrical

Conductivity and insulation.

Electrical Resistivity

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

Dielectric Strength

17 kV/mm432 V/mil
15 kV/mm381 V/mil

Dielectric Constant (1 MHz)

8.8
7.9

Dissipation Factor (1 MHz)

5×10⁻⁴
0.002

Volume Resistivity

1×10¹⁴ Ω·cm
1×10¹³ Ω·cm

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

85 / 100
90 / 100

Manufacturability

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

Machinability

5 / 100
4 / 100

Sintering / Firing Temperature

1,800°C3,272 °F
1,750°C3,182 °F

Same in both: Polishability 85 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

280 MJ/kg120,378 BTU/lb
230 MJ/kg98,882 BTU/lb

Embodied Carbon (primary production)

22 kg CO₂/kg
14 kg CO₂/kg

Embodied Water

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)

61 kN·m/kg
108 kN·m/kg

Specific Stiffness (E / density)

98.2 MN·m/kg
88.6 MN·m/kg

Thermal Diffusivity

74.6 mm²/s
9.4 mm²/s

Thermal Shock Resistance Index

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 scale

Manufacturing and finishing

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

AlN vs Sialon — frequently asked

Is Sialon stronger than AlN?

Yes. Sialon has a typical tensile strength of 350 MPa (50.8 ksi) against 200 MPa (29 ksi) for AlN — about 75% more.

Which is cheaper, AlN 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 AlN over Sialon?

Pick Sialon when strength drives the design, or when surface hardness matters.

Ready to make it?

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