# Pyrolytic Boron Carbide

Pyrolytic boron carbide is a grade of boron carbide. The graph bars on the material properties cards below compare pyrolytic boron carbide 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

2120 *MPa* 310 *x 10 ^{3} psi*

Elastic (Young's, Tensile) Modulus

240 *GPa* 34 *x 10 ^{6} psi*

Flexural Strength

170 *MPa* 25 *x 10 ^{3} psi*

Fracture Toughness

3.5 *MPa-m ^{1/2}* 3.2

*x 10*

^{3}psi-in^{1/2}Knoop Hardness

3150

Poisson's Ratio

0.19

Tensile Strength: Ultimate (UTS)

350 *MPa* 51 *x 10 ^{3} psi*

## Thermal Properties

Maximum Temperature: Mechanical

2500 *°C* 4530 *°F*

Melting Onset (Solidus)

2470 *°C* 4480 *°F*

Specific Heat Capacity

950 *J/kg-K* 0.23 *BTU/lb-°F*

Thermal Conductivity

31 *W/m-K* 18 *BTU/h-ft-°F*

Thermal Expansion

5.3 *µm/m-K*

## Other Material Properties

Density

2.1 *g/cm ^{3}* 130

*lb/ft*

^{3}Dielectric Constant (Relative Permittivity) At 1 MHz

6.4

Dielectric Strength (Breakdown Potential)

56 *kV/mm* 2.2 *V/mil*

Electrical Resistivity Order of Magnitude

11 *10 ^{x} Ω-m*

## Common Calculations

Stiffness to Weight: Axial

63 *points*

Stiffness to Weight: Bending

99 *points*

Strength to Weight: Axial

47 *points*

Strength to Weight: Bending

53 *points*

Thermal Diffusivity

16 *mm ^{2}/s*

Thermal Shock Resistance

20 *points*

## Followup Questions

## Further Reading

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