Conventional Sintering for Unconventional Performance: Robust Amorphous Carbon/Diamond Composites

Conventional C/C composites often suffer from weak interfacial bonding, limiting their mechanical performance. While recent high-pressure synthesis has successfully integrated diamond reinforcements into amorphous carbon matrices via strong covalent interfaces, it remains challenging to achieve such composites under moderate processing conditions. Here, we report the synthesis of a composite consisting of disordered graphitic carbon and submicron diamond via conventional sintering without applying extreme pressure. The combined amorphization of C 60 and partial graphitization of diamond leads to the formation of an integrated interface, which comprises graphitic layers derived from diamond, which bond to the diamond on one side and are linked to the disordered graphitic carbon matrix on the other, effectively bridging the two phases. This unique architecture enables the composite to exhibit an outstanding combination of mechanical, electrical, and tribological properties. With a low density of 1.49 g/cm 3 , the composite demonstrates a hardness of 4.6 GPa and a bending strength of 130.4 MPa—significantly surpassing those of commercial graphite and type-II glassy carbon (GC)—while maintaining electrical conductivity on the same order of magnitude as the disordered graphitic carbon. Moreover, the one-step sintering process contrasts with the complex, multi-step routes required for conventional graphite, C/C composites, and amorphous carbons. The superior integrated performance, coupled with the simple and scalable fabrication, positions this material as highly promising for demanding applications such as medical implants, high-temperature electrodes, and key components in semiconductor manufacturing and aerospace systems.