Microstructure and Properties of C/SiC-Diamond Composites Prepared by the Combination of CVI and RMI

Diamond modified continuous carbon fiber reinforced silicon carbide (C/SiC-Diamond) composites are prepared using a combination of chemical vapor infiltration (CVI) and reactive melt infiltration (RMI). The effect of the diamond particle size on the microstructure, mechanical properties, and thermophysical properties of C/SiC-Diamond composites are investigated. A density of 2.05 g cm⁻³ is achieved for C/SiC-Diamond composites impregnated with 1 µm diamond particles. A near twofold enhancement of the thermal conductivity (9–10 W (m K)⁻¹) and thermal diffusion coefficient (5 mm² s⁻¹) is obtained, compared with continuous carbon fiber reinforced silicon carbide (C/SiC) composites (5–6 W (m · K)⁻¹) prepared by CVI. It is established that the introduction of diamond can improve the thermal conductivity of C/SiC composites and increase the application potential in rocket engines, aerospace vehicles, and brake materials.