Preparation and characteristics of multiwalled carbon nanotubes reinforced boron carbide composites

AbstractBoron carbide reinforced with multiwalled carbon nanotubes were prepared by hot pressing at 1850°C under vacuum and 60 MPa pressure. Silicon powder was used as a sintering aid to decrease the sintering temperature of boron carbide. The results showed that the additions of silicon and multiwalled carbon nanotubes improved the mechanical properties of boron carbide ceramic. For the specimen with 1 wt-% multiwalled carbon nanotubes and 8 wt-% silicon, flexural strength of 506 MPa and fracture toughness of 5·70 MPa m1/2 were achieved. Microstructures of boron carbide composites were observed by means of SEM. The increased mechanical properties of the composites are mainly attributed to the high relative density, the change of fracture mode and the pulling out of multiwalled carbon nanotubes.