HOT-PRESSED BORON NITRIDE

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:

              Dielectric Strength (Volts/mm):                                                                      35,000

              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