The effect of carbon nanotubes introduction on the mechanical properties of reaction bonded boron carbide ceramics

摘要

The influence of carbon nanotubes (CNTs) on the mechanical properties and structure formation during reactive sintering of B4C materials with Si addition was studied. Upon infiltrating the B4C structure with molten silicon, a non-porous composite was formed with a density of 2.45-2.55 g/cm3 and a hardness of 22-27 GPa. The formation of highly dispersed B-C-Si phases was observed in the interphase of adjacent B4C particles due to the incorporation of Si into B4C structures. These phases increase the bonding strength between B4C particles. In spite of the fact that the addition of 1-5 wt% Multi-Walled Carbon Nanotubes decreases the green density of the compacts, the flexural strength of the infiltrated material significantly increased. The improvement of the strength of ceramics modified with MWCNTs was interpreted in terms of the formation of thin flattened SiC crystals at the interfaces between B4C and B-C-Si particles, which strengthen the interfaces between ceramic particles.