Grade: HBR

Typical Analysis in Percent:

              B                        42 - 43.8

              N                        52.7 - 54.1

              O(max)                3.9

              C                        <0.1

              Ca(min)                0.8

              Other(max)           0.05

Density (Minimum): 1.90 g/cm³

Specific Heat: 0.441 (Cal ⋅ g^-1 ⋅ ^oC^-1 @ 700 ^oC)

Maximum Recommended Operating Temperature (Oxidizing Atmosphere): 850 ^oC

Maximum Recommended Operating Temperature (Inert Atmosphere or Vacuum): 1100 ^oC - 1600 ^oC

                                                                                         Parallel                     Perpendicular

                                                                                      To Pressing                  To Pressing    

                                                                                         Direction                      Direction         

Electrical Properties:

              Volume Resistivity @ R.T. (Ω -cm):                                         1 x 10¹³

              Dielectric Constant:                                             4.6                                     4.2

              Loss Tangent @ 8GHz:                                     .00055                                 .00053

Thermal Conductivity (Cal ⋅ cm^-1 ⋅sec^-1 ⋅ ^oC^-1):

              @ 25 ^oC:                                                           0.13                                      0.08

              @ 500 ^oC:                                                         0.08                                      0.06

              @ 800 ^oC:                                                         0.07                                      0.05

Coefficient of Thermal Expansion:

              RT to 1200 ^oC (in/in ^oC x 10^-5):                          1.0                                        2.0

Flexural Strength (psi):

              @ 25 ^oC:                                                           6,000                                   7,500

              @ 1500 ^oC:                                                       2,700                                   3,100

Modulus of Elasticity (10⁶ psi):                                        9                                         7

Compressive Strength (psi):                                          8,700                                   9,200