Microstructure and Properties of the Sintered Diamond Reinforced by Diamond-MWCNTs Composite Fibers
A new type of sintered diamond reinforced by diamond-MWCNTs composite fibers which were randomly orientated and even distributed in the diamond matrix was synthesized by using 3(wt)% mullti-walled carbon nanotubes(MWCNTs) as starting additive under high pressure of 5.8GPa at temperature of 1500°C for 1 min. A special polycrystalline diamond structure of direct bonding of both diamond to diamond and diamond to diamond-MWCNTs composite fiber was observed. The testing results show that it possesses not only high hardness (49-52GPa) and Young’s modulus (878GPa) but also high bending strength (1320~1540GPa) and fracture toughness (9.0~9.2MPa•M1/2) as it was theoretically predicted. The high performances of the composite were contributed to the fiber strengthening effect and the special structure which can offer more extensive diamond to diamond bonding.
F. M. Deng et al., "Microstructure and Properties of the Sintered Diamond Reinforced by Diamond-MWCNTs Composite Fibers", Solid State Phenomena, Vol. 175, pp. 1-7, 2011