# Pyrolytic Boron Nitride

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

## Thermal Properties

Maximum Temperature: Corrosion

1140 *°C* 2080 *°F*

Maximum Temperature: Mechanical

2350 *°C* 4260 *°F*

Maximum Thermal Shock

1720 *°C* 3130 *°F*

Specific Heat Capacity

840 *J/kg-K* 0.2 *BTU/lb-°F*

Thermal Conductivity

42 *W/m-K* 24 *BTU/h-ft-°F*

Thermal Expansion

18 *µm/m-K*

## Electrical Properties

Dielectric Constant (Relative Permittivity) At 1 MHz

4.3

Dielectric Strength (Breakdown Potential)

200 *kV/mm* 7.8 *V/mil*

Electrical Dissipation At 1 Hz

0.0017

Electrical Dissipation At 1 MHz

0.0018

Electrical Resistivity Order of Magnitude

15 *10 ^{x} Ω-m*

## Other Material Properties

Compressive (Crushing) Strength

250 *MPa* 37 *x 10 ^{3} psi*

Density

2.1 *g/cm ^{3}* 130

*lb/ft*

^{3}Elastic (Young's, Tensile) Modulus

23 *GPa* 3.3 *x 10 ^{6} psi*

Flexural Strength

140 *MPa* 20 *x 10 ^{3} psi*

Poisson's Ratio

0.11

Tensile Strength: Ultimate (UTS)

40 *MPa* 5.8 *x 10 ^{3} psi*

## Common Calculations

Stiffness to Weight: Axial

6.0 *points*

Stiffness to Weight: Bending

45 *points*

Strength to Weight: Axial

5.3 *points*

Strength to Weight: Bending

12 *points*

Thermal Diffusivity

24 *mm ^{2}/s*

Thermal Shock Resistance

7.1 *points*

## Followup Questions

## Further Reading

Handbook of Refractory Carbides and Nitrides: Properties, Characteristics, Processing and Applications, Hugh O. Pierson, 1996

Ceramics and Composites: Processing Methods, Narottam P. Bansal and Aldo R. Boccaccini (editors), 2012

IEC 60672-3: Ceramic and glass-insulating materials - Part 3: Specifications for individual materials

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