Diamond composites of high thermal conductivity and low dielectric loss tangent

Abstract Diamond-CaMg(CO3)2 and diamond-CaCO3 compacts were produced. Maximum values of high thermal conductivity of 540 W/m K, electrical resistivity of 2∙1011 ohm cm, dielectric constant of 47, and dielectric loss tangent of 5.8∙10-3 at 106 Hz were achieved. The composites based on diamonds were sintered at a high pressure of 8.0 GPa and temperature of 2100 °C and were characterised by high ratios of direct bonding between the diamond grains. Diamond grain size varied from 12 to 45 µm. The CaCO3 content of the diamond-CaCO3 composites and the CaMg(CO3)2 content of the diamond-CaMg(CO3)2 composites were 8.5 vol% and 8.8 vol%, respectively. The materials developed are recommended for use as heat sinks in a wide range of electronic devices.