Pressure Sintered (Hot Pressed) Silicon Nitride
Hot pressed silicon nitride is silicon nitride in the hot isostatic pressed (HIP) condition. The graph bars on the material properties cards below compare hot pressed 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
2810 MPa 410 x 103 psi
Elastic (Young's, Tensile) Modulus
310 GPa 45 x 106 psi
Flexural Strength
810 MPa 120 x 103 psi
Fracture Toughness
6.2 MPa-m1/2 5.6 x 103 psi-in1/2
Knoop Hardness
1570
Poisson's Ratio
0.27
Tensile Strength: Ultimate (UTS)
510 MPa 74 x 103 psi
Thermal Properties
Maximum Temperature: Mechanical
1330 °C 2420 °F
Maximum Thermal Shock
750 °C 1380 °F
Specific Heat Capacity
720 J/kg-K 0.17 BTU/lb-°F
Thermal Conductivity
31 W/m-K 18 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
8.2
Dielectric Strength (Breakdown Potential)
18 kV/mm 0.7 V/mil
Electrical Resistivity Order of Magnitude
12 10x Ω-m
Common Calculations
Stiffness to Weight: Axial
53 points
Stiffness to Weight: Bending
69 points
Strength to Weight: Axial
44 points
Strength to Weight: Bending
44 points
Thermal Diffusivity
13 mm2/s
Thermal Shock Resistance
37 points
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