Multiwall carbon nanotube-SiO2 nanocomposites:: Sintering, elastic properties, and fracture toughness

Carbon nanotubes (CNT) are the most studied nanostructured materials for a broad range of applications because of its mechanical and physical properties. CNT have high Young's modulus of 1500GPa, great tensile strength of 100GPa and a very high diameter ratio of 1000, high electric and thermal conductivity. Single walled carbon nanotubes-alumina-based composites were consolidated by using spark-plasma sintering (SPS), and the results showed a great fracture toughness of 9.7 MPa m1/2. Multiwall carbon nanotubes (MWCNT) are homogeneously dispersed in colloidal silica using attrition milling technique, and the obtained powder mixtures are consolidated by spark-plasma sintering. Elastic moduli and fracture toughness of the nanocomposites were determined using ultrasonic and Vickers indentation technique. The toughening mechanisms of the nanocomposites include crack deflection, nanotube pullout, nanotube elastic bridging, and frictional nanotube bridging.