Colloidal processing of carbon nanotube/alumina composites

Preparation of carbon nanotube (CNT)/alumina composites by a simple colloidal processing method has been reported in this paper. The surface modification process of carbon nanotubes was characterized by means of zeta potential measurements and TEM microscopy. The addition of only 0.1 wt % carbon nanotubes in the alumina composite increases the fracture toughness from 3.7 to 4.9 MPa.m(1/2). Microstructure characterization, performed by SEM, showed that the bridging effect on cracks, the tight bonding between CNTs and alumina matrix, and the pullout of CNTs from matrix are possible mechanisms leading to the improvement of the fracture toughness.