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
1450
Poisson's Ratio
0.25
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
Density
3.2 g/cm3 200 lb/ft3
Dielectric Constant (Relative Permittivity) At 1 MHz
8.0
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