Home Products Composites | Compounds | Ceramics Beryllium Oxide Ceramics Thermalox® CR THERMALOX CR BERYLLIA Thermalox CR Beryllia ceramic components convey an exceptional combination of properties: Second only to Diamond among electrical insulating materials, Thermalox CR material is an exceptionally high purity crucible material with excellent etch resistance. Low Dielectric Constant (6.76) and low tanδ dielectric loss tangent (.0004 at 1 MHz), permitting improved circuit performance at high frequencies. A Coefficient of Thermal Expansion (CTE) of 9.0 intermediate to silicon or gallium arsenide and metals. Ten times greater thermal conductivity than alumina ceramics. Contact Materion Ceramics For more information about Materion Ceramics' Thermalox CR or other beryllium oxide materials, please contact Materion Ceramics.