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Silicon Nitride (Si3N4)

Silicon nitride is a non-oxide engineering ceramic. It can have a moderately low thermal conductivity among the non-oxide engineering ceramics in the database.

The properties of silicon nitride include four common variations. This page shows summary ranges across all of them. For more specific values, follow the links immediately below. The graph bars on the material properties cards further below compare silicon nitride to other non-oxide engineering ceramics (top) and the entire database (bottom). A full bar means this is the highest value in the relevant set. A half-full bar means it's 50% of the highest, and so on.

Mechanical Properties

Compressive (Crushing) Strength

600 to 2950 MPa 87 to 430 x 103 psi

Elastic (Young's, Tensile) Modulus

140 to 310 GPa 20 to 45 x 106 psi

Flexural Strength

130 to 810 MPa 18 to 120 x 103 psi

Fracture Toughness

3.1 to 6.2 MPa-m1/2 2.9 to 5.6 x 103 psi-in1/2

Poisson's Ratio

0.24 to 0.27

Thermal Properties

Maximum Temperature: Mechanical

1000 to 1330 °C 1830 to 2420 °F

Maximum Thermal Shock

290 to 750 °C 550 to 1380 °F

Specific Heat Capacity

720 to 800 J/kg-K 0.17 to 0.19 BTU/lb-°F

Thermal Conductivity

12 to 31 W/m-K 7.0 to 18 BTU/h-ft-°F

Thermal Expansion

2.5 to 3.2 µm/m-K

Other Material Properties


2.2 to 3.4 g/cm3 140 to 210 lb/ft3

Dielectric Constant (Relative Permittivity) At 1 MHz

8.0 to 10

Dielectric Strength (Breakdown Potential)

18 kV/mm 0.7 V/mil

Electrical Resistivity Order of Magnitude

11 to 12 10x Ω-m

Common Calculations

Stiffness to Weight: Axial

34 to 53 points

Stiffness to Weight: Bending

65 to 78 points

Thermal Diffusivity

7.5 to 13 mm2/s

Followup Questions

Further Reading

Silicon Nitride and the Sialons, Vivien Mitchell, 1993

Handbook of Refractory Carbides and Nitrides: Properties, Characteristics, Processing and Applications, Hugh O. Pierson, 1996

IEC 60672-3: Ceramic and glass-insulating materials - Part 3: Specifications for individual materials

Springer Handbook of Condensed Matter and Materials Data, W. Martienssen and H. Warlimont (editors), 2005

Sintering of Advanced Materials: Fundamentals and Processes, Zhigang Zak Fang (editor), 2010