Potassium Bromide (KBr) Optical Material
Potassium bromide is a non-glass, inorganic optical material. It has a moderately low density among the non-glass optical ceramics in the database. The graph bars on the material properties cards below compare potassium bromide to other non-glass optical 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
Elastic (Young's, Tensile) Modulus
24 GPa 3.4 x 106 psi
Poisson's Ratio
0.17
Shear Modulus
7.0 GPa 1.0 x 106 psi
Thermal Properties
Melting Onset (Solidus)
730 °C 1350 °F
Specific Heat Capacity
450 J/kg-K 0.11 BTU/lb-°F
Thermal Conductivity
4.8 W/m-K 2.8 BTU/h-ft-°F
Thermal Expansion
39 µm/m-K
Electrical Properties
Dielectric Constant (Relative Permittivity) At 1 MHz
4.9
Electrical Dissipation At 1 MHz
0.00020
Otherwise Unclassified Properties
Density
2.8 g/cm3 170 lb/ft3
Light Transmission Range
0.22 to 26 µm
Refractive Index
1.8
Common Calculations
Stiffness to Weight: Axial
4.7 points
Stiffness to Weight: Bending
35 points
Thermal Diffusivity
3.9 mm2/s
Followup Questions
Further Reading
Handbook of Optical Materials, Marvin J. Weber, 2003
Handbook of Optical Constants of Solids, Edward D. Palik (editor), 1998
CRC Materials Science and Engineering Handbook, 4th ed., James F. Shackelford et al. (editors), 2015