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Pressureless Sintered Silicon Nitride

Pressureless sintered silicon nitride is a grade of silicon nitride. The graph bars on the material properties cards below compare pressureless sintered 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

2950 MPa 430 x 103 psi

Elastic (Young's, Tensile) Modulus

300 GPa 44 x 106 psi

Flexural Strength

660 MPa 95 x 103 psi

Fracture Toughness

5.6 MPa-m1/2 5.1 x 103 psi-in1/2

Knoop Hardness


Poisson's Ratio


Thermal Properties

Maximum Temperature: Mechanical

1300 °C 2370 °F

Maximum Thermal Shock

600 °C 1110 °F

Specific Heat Capacity

780 J/kg-K 0.19 BTU/lb-°F

Thermal Conductivity

29 W/m-K 17 BTU/h-ft-°F

Thermal Expansion

3.2 µm/m-K

Other Material Properties


3.2 g/cm3 200 lb/ft3

Dielectric Constant (Relative Permittivity) At 1 MHz


Dielectric Strength (Breakdown Potential)

18 kV/mm 0.7 V/mil

Electrical Resistivity Order of Magnitude

11 10x Ω-m

Common Calculations

Stiffness to Weight: Axial

52 points

Stiffness to Weight: Bending

70 points

Thermal Diffusivity

12 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

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