SiAlON
SiAlON is a non-oxide engineering ceramic. It has a moderately high fracture toughness among non-oxide engineering ceramics. In addition, it has a very low thermal conductivity and a moderately high density. The graph bars on the material properties cards below compare SiAlON 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
2620 MPa 380 x 103 psi
Elastic (Young's, Tensile) Modulus
290 GPa 43 x 106 psi
Flexural Strength
680 MPa 99 x 103 psi
Fracture Toughness
6.3 MPa-m1/2 5.7 x 103 psi-in1/2
Knoop Hardness
1700
Poisson's Ratio
0.23
Shear Modulus
120 GPa 17 x 106 psi
Tensile Strength: Ultimate (UTS)
190 MPa 28 x 103 psi
Thermal Properties
Maximum Temperature: Mechanical
1200 °C 2190 °F
Maximum Thermal Shock
300 °C 570 °F
Specific Heat Capacity
880 J/kg-K 0.21 BTU/lb-°F
Thermal Conductivity
19 W/m-K 11 BTU/h-ft-°F
Thermal Expansion
3.6 µm/m-K
Other Material Properties
Density
3.3 g/cm3 210 lb/ft3
Dielectric Constant (Relative Permittivity) At 1 MHz
9.3
Dielectric Strength (Breakdown Potential)
8.3 kV/mm 0.33 V/mil
Electrical Resistivity Order of Magnitude
14 10x Ω-m
Common Calculations
Stiffness to Weight: Axial
50 points
Stiffness to Weight: Bending
67 points
Strength to Weight: Axial
16 points
Strength to Weight: Bending
22 points
Thermal Diffusivity
6.4 mm2/s
Thermal Shock Resistance
13 points
Followup Questions
Further Reading
Silicon Nitride and the Sialons, Vivien Mitchell, 1993
Springer Handbook of Condensed Matter and Materials Data, W. Martienssen and H. Warlimont (editors), 2005
CRC Materials Science and Engineering Handbook, 4th ed., James F. Shackelford et al. (editors), 2015